Luckily I only lost power for 1 day following the storm. So I had a lot of time to play around with my newly constructed 3D printer. One of the first parts I made was a Quick Change Tool Post (QCTP) Tool Holder that would attach to the back of my Grizzly G0602 lathe’s backsplash. Here you can see 5 tool holder storage brackets clipped in place, with my trusty Diamond Tool Holder hanging on the first bracket.

I have an AXA (#100) piston-style QCTP and I needed a good way to store my tool holders. My tool holders were too tall to fit into all but the biggest drawer on my Kennedy tool chest, and I had other stuff occupying that space. So my tool holders always seemed to sit on the benchtop or on a clean part of my chip tray near my tailstock. Not ideal. I’ve knocked them off more than once – and they ALWAYS land cutting-edge down.

Then Norman sent me some cast aluminum tool holders that were an excellent yet simple solution to the problem. But they needed to be mounted to the wall to be used effectively. I didn’t have a wall nearby to bolt them to (I have metal shelving along every square foot of my shop walls) so I bolted them to a piece of 2×4 and clamped that near my lathe. That worked, but it wasn’t an ideal solution either.

So instead I took cues from Normans design and created an ABS plastic version that would clip to my G0602 backsplash. I’m very pleased with the results! Here’s a closeup:

The parts aren’t perfectly smooth like what you’d expect from an injection molded part. But then again, they don’t need to be smooth to perform their function. My 3D printer lays down layers of plastic in very thin (.010 or less) layers with an accuracy/resolution of .003 to .005 – just fine for a part like this. Each part takes a little over an hour to print, so they aren’t as quick to manufacture as an injection molded part either. But the setup cost for an injection mold for a part like this would be in the thousands just to have the mold made. I think that’s probably the reason nobody has bothered to manufacture a part like this before – they’d have a hard time making their money back on the initial mold investment if they sold the parts for $10 a piece. But having the ability to print a part like this eliminates the financial barriers associated with bringing it to market.

I’m going to list a few of these on eBay at $8 each. If ProjectsInMetal members/visitors would like to buy some I’ll sell them for $7 and cut eBay and their fees out of the equation. They are very light and thus inexpensive to ship. About $4 for the set of 5 that I sent to Norman (from Seattle to Texas via First Class Mail). Shipping outside the USA will be a bit more, but I won’t overcharge.

If the parts prove popular and a lot of people buy them I may look a little harder into an injection mold. But for now I’m extremely happy with the printed version. They are very strong (you’d have to try hard to break them) and fit my tool holders very well. As for the backsplash, the G0602 has a lip that is folded forward .06, and down .05. If you have a different backsplash with similar dimensions the brackets would probably fit with little to no modification. But if necessary they could be easily filed to fit a slightly larger backsplash lip. They won’t, however, fit a backsplash folded the opposite direction. But I could easily re-design the clip if you’ve got a lathe with different dimensions. Just let me know.

If you’d like to purchase, please use the PayPal button below. If you have trouble using the PayPal button, please send me a private message via the forum. Right now the only color I have is Black, and I have 10 in stock (but I can make more). Thanks!

G0602 QCTP Tool Holder Storage Bracket: $7 USD 

To leave a comment join the forum discussion on this post

The problem.

The solution.

Here we see the tailstock as a whole:

Finished camlock.

So I started by machining a new clamp plate, this measures 42.00mm by 25.4mm. It is 5.7mm thick. The grooves come in 8.5mm from each edge and are 2 mm deep. The hole is 10mm in diameter and is 15 mm from the right hand edge and 13.5 mm from the front edge (closest to the camera in this picture)

The clamp plate.

Next I machined a clamp bolt from 10mm steel bar (of unknown grade) which was threaded on both ends using an M8 die. The bolt is 56.3mm in length, the larger threaded portion is 12.2mm to the shoulder, the smaller threaded portion is 9.2mm to the shoulder. Then I attached a bolt on the end, and put it in the lathe to shorten the length of the nut so that it would clear the bed.

The clamp bolt.

Next I made a cam receiver, it was made from 12.7mm hex stock, centerdrilled then drilled to 6.8mm, then tapped M8, once this was done, it was cross drilled 8mm.

The receiver is 17.6mm in length. The cross drilled hole is halfway along the length.

The Receiver

After these were done, I made the cam. This was done by offsetting the work in the four jaw chuck. This would be easier to do on an individual four jaw, but I don’t have one, I only have a self centering so I offset it by putting some packing material in. The cam was made from 10mm steel (unknown grade) and is 47.2mm in length. The offset portion is 13mm long and 7.8mm in diameter.

Turning the cam.

I did this at quite a slow speed, because I was worried about the work coming out. I wasn’t sure how secure it was. Either way it turned out well.

Finished cam with handle attached.

The cam was pressed into a bit of steel that had been drilled to the same size as the cam, then cross drilled to accommodate the handle.

Here is an overview of the parts

The only thing missing from the image above is a spring that is used to keep the clamp plate away from the ways when it is unlocked.

In Use:

Here the tailstock is unlocked.

Here it is locked.

Note the nice knob on the end of the handle, this was made using my ball turning attachment. I haven’t shown the handle because the dimensions aren’t critical.

To conclude:

This has been a very worthwhile project, saving me lots of time and frustration. If I was to make it again I would make the part of the cam that goes into the receiver slightly longer, so that I could put a circlip on it so that it wouldn’t come out.

Although this is for the Clarke Lathe, I’m sure that you would be able to modify it for your machine. As promised, here are the plans:

Thanks for reading.

By Gareth Bellringer About the Author

To leave a comment join the forum discussion on this post

Here’s Gareth Bell’s Captive Nut:

And here’s another version by Jerry:

It’s a great project for the beginner for a couple of reasons, but mostly because it allows you to practice single-point threading. Once you’re done you’ve got quite the conversation piece that will puzzle and entertain kids and adults alike.

For more information (including links with directions on how to make your own) visit the original forum post by Gareth.

1. Introduction
2. Material Selection
3. Outside turning
4. Boring
5. Threading
6. Spanner Slots
7. Finish Work
8. Conclusion

1.) Introduction

One of the main reasons I purchased my Grizzly 10×22 lathe was to assist in the project to convert my milling machine to CNC control and it has worked out fantastically for that purpose.  I have made many parts already using it and performed follow-up work on it from milled parts as well.  However when it came time to work on the long, slender, ball screws needed for the X and Z axis it became clear that I needed a little rear support.  My first attempt at cutting the Z axis screw ends resulted in a wobbling screw in part due to the rear of that long screw whipping around behind the lathe I believe.

Before I made any more attempts at taking on long shafts I wanted a way to really dial them in to the lathe rotation axis.  A rear spider is used by many gunsmiths to do just this but they are often either bulky or installed on the work and butted against the spindle meaning that moving the work involves also moving the spider.  I started thinking about what I wanted to do and how I wanted mine to work.

My design goals were:

• I wanted it to be attached, something that was just an extension of the lathe.
• As short as possible.  I wanted it to be able to grab any bar that could reach the rear of the spindle bore and to not protrude much from the rear cover.
• The rear cover needed to be able to be opened and closed with the spider in place but not in use.
• I wanted a decent appearance, something that looked like it belonged there.

I settled on a design that would replace one of the spanner nuts on the rear spindle of the lathe and provide a short extension of the spindle to add the 4 set screws used in the spider.  The extension would be just a bit over ½” with a heavy chamfer to make it less obtrusive and keep the rear cover from contacting it when opened and closed.  I proceeded to take a few measurements to get started on the 3D model.

Original spindle spanner nuts

I determined that the thread used on the rear spindle was M39-1.5 which is not what is listed in the parts diagram or the replacement parts site on Grizzly.  I have no idea if that is due to changes over time or just a misprint so you may want to confirm that against your own spindle before cutting any threads or finishing the boring work.

The inside bore of the lathe is just a tad over 1 inch so I went with 1.060” for the bore of my spider to match that and go a little over it.  The hole in the rear cover was around 2 inches wide but poorly centered on the spindle.  You can adjust it to some extent but it would not center well on my lathe so I decided on the outside diameter of the spider portion of the part being 1.750” to give plenty of clearance for both opening the door and so it doesn’t rub on the off-center hole.

The O.D. of the nut section of the part was chosen to be the same as the existing nut at around 2.230”.  Not much of this is critical so it can be altered to suit the user or material at hand.

2.) Material Selection

There is not a lot to say here really.  I wanted the nut to be durable and hold up to being yanked around with a spanner wrench and getting smacked now and again by hard metals.   What I had on hand was a hunk of 2.5” diameter  1144 steel that I had snagged from the scrap bin.  It also happened to be short enough to not need to be cut down much to get to final dimensions.   I think AL could be used but durability would suffer while ease of machining would increase.  Also if you could find a 2.5” tube with a 0.750” wall thickness you could cut down a lot of time spent boring but the cost would likely be high for the material.

3.) Outside Turning

This is pretty straight forward.  Since perfect concentricity is not required I simply used the 3 jaw for all the operations.  First I faced each side of the stock to clean up the rough ends.  The Spider-Nut needs two external diameters cut; the 2.230” external diameter of the nut section and the 1.750” section for the spider section.  The total length of the part is 1.180”.  In my case the raw stock was short enough that I could not cut both ODs at the same time.  If you use a longer piece of stock then consideration will need to be given to cutting away the excess, as 2.25 to 2.5” of steel is no simple thing to part off and facing off inches of material is also not fun.

I used standard carbide tools to turn the majority of the stock away.  750RPM to 1200RPM and 0.050” DOC with a heavy feed was showering the area in nice blue chips.  Then when it was time to get a nice smooth finish I switched to the CCGT inserts normally used in aluminum but they also do very nice work with small DOC in steel.  They are sharp enough to remove small amounts of material where normal molded inserts will only rub and make a mess.  1200RPM, 0.005” DOC and low feed provided a nice finish.

Then I faced each end down to the proper length but on my part I left the spider section about 0.500” long for now so I had some extra to grab onto for boring and threading work.

4.)  Boring

Since I began with solid round stock there was a LOT of material to remove for this step.  I began with drilling a center in the back of the stock (the nut side) and then used progressive drills to step up through the sizes from 3/16” on up to 5/8”.  I stepped up by roughly 1/8” with each drill but I have found the 5/8” drill cuts better going from 3/8” than it does from 1/2” so in that case I stepped up by 1/4″.

With the starter hole punched through I could use my 1/2” boring bar for my best chance at boring the hole without chatter.   The 1.680” length of the bore would be right at 3.4X extension on the boring bar which is approaching the limit on a 1/2” steel boring bar and my carbide inserts do not make things better at long extensions for chatter.  Still I like to use them where possible because removing a lot of metal with HSS on a steel part is like watching paint dry.

I used 1200RPM and 0.020” DOC and an aggressive feed on the rough boring work.  Since the through bore was not critical I simply used the roughing insert all the way through.  As the hole opened up the finish improved a bit but I had to step down to 720RPM near the end to quell some chatter.  Once the through bore ID reached 1.060” I stopped and reset for the next operation.

Next step was to bore the hole for what would soon be the threaded nut side.  The minor diameter I came up with by measuring the inside of one of the stock spanner nuts was 1.480” or about 37.6mm.  I stayed on the loose side as it was more important that it fit easily than perfectly snug.  It’s a jam nut not a rocket nozzle.  This is a much shorter boring job so I adjusted the boring bar to just 0.700” of overhang and using a magnetic dial indicator against the carriage I measured out the 0.680” bore depth from the face of the part and set my carriage stop for that position.  I could rough using the carbide inserts much more aggressively now.

After roughing out the majority of the bore I switched to my AR Warner HSS inserts for my boring bar and slowed the spindle way down into the low hundreds.  These sharp HSS inserts will take smaller cuts and leave a nicer finish behind but they are remarkably slow to use.  I cut by 0.005” plus a spring-pass till I reached my target diameter on the nose.

5.)  Threading

Lathe threading is a topic covered all over the web in great detail.  I am not going to completely cover that topic here but there are a few gotcha’s if you have not done an internal thread nor threaded on the Grizzly 10×22 before.  If this is the first time you have threaded, stop here.  You need to practice it a bit with setups where it is harder to crash.  A flub here wastes a lot of time spent up to now.

Compound setup for internal threading

Since this is a metric thread you need to be aware that you cannot use the thread dial to engage and disengage the half-nuts.  They MUST remain closed through the entire threading operation.  This means that you will have to run the lathe in reverse to back the tool up out of the bore for the next pass.  As this is an internal bore, the compound position will need to be the mirror image of the normal position, being swung either 29° to the left-front or 29° to the right rear (see picture above).  The position on the compound angle dial will not be 29° either.  The 10×22 has its zero angle mark set where the compound is parallel to the axis of the spindle instead of perpendicular like most lathes.  Instead on the 10×22 you set the compound to 61° (90° – 29°).  Clear as mud right?

To do this job you need a 60° thread cutting tool of some kind that can thread inside a bore.

A carbide lay-down thread tool.

That tool must be sharply pointed enough to cut the root of the thread to the right depth before it cuts the sides of the thread too wide.  You need a tool made for this or you need to grind one that will work which is a subject all to itself.  I went with a carbide insert tool with a lay-down configuration.  It looks a lot like a boring bar, but with a bit different geometry.  An insert tool means I can do more work on projects and less work grinding tools.

Before I began, I made a copy of the spindle’s rear thread on some stock I had laying around.  I cut the thread so that the rear spanner nut from the machine would thread on freely to male thread I was making.  This would then give me a gauge to use when cutting the female threads for the nut and should mean that if this gauge threads in that the spider-nut would certainly thread onto the rear of the spindle.  Time well spent; because if you remove the work from the chuck you are in a world of hurt trying to pick up the thread again if it does not fit.  It may still be prudent to mark the chuck jaw and part together so it can be replaced in the chuck in the same position if need be.

Copy of rear spindle thread with spanner nut threaded onto it

Before you begin to cut your thread use the tool to make a relief groove at the back of the bore.  This is a shallow groove about 0.050” deep and perhaps 0.100” wide at the back of the bore for the threads.  This allows the tool to clear from the material at the end of each threading pass. So you don’t have the tool running into a mound of burr at the end of the thread.

Setup a reference of some kind to show you where the end of the bore is so you don’t crash the tool trying to eyeball it.  You can use tape, dye, or something else.  I use my carriage stop for this but you still have to turn off the spindle at the right moment to allow it to coast up to the stop since it will not stop the power feed if the spindle is running.  Now, find your cross-slide zero by just scratching the inside of the bore.  Finally with the spindle off pick up a number you want to use on the thread dial and engage the half-nuts at that position.  I chose position ‘1’. (remember you must not disengage them again till the thread is finished)

For each pass I followed the below procedure:

1. Set cross slide to your zero position.
2. Dial the desired depth of cut for this pass on the compound.
3. Turn the spindle on forward and make the pass.
4. 1/8” or better from your reference mark turn the spindle off.
5. Turn the spindle by hand all the way up to the mark if needed.
6. Push the cross-slide forward by 0.045” to 0.055” and
7. Turn the spindle on in reverse till you are clear of the bore.
8. Stop the spindle.
9. Back to step 1.

I continued that process until I had cut in by 0.041” of compound in-feed (Use that as a guide, your mileage may vary depending on the tool you are using). At this point the thread gauge I had made would just thread on.  I gave it an extra 0.001” of compound feed and that made for a nice snug but free spinning fit.  Threading was now complete.

6.) Spanner Slots and Screw Holes

The next step is to add the spanner slots in the outer body of the spider nut.  There are multiple ways to do this that depend on the equipment you have at hand.  The position is not critical so by-eye alignment is fine but too much slop and it would start to look bad.  I happened to have a shop-made indexer I made for just these kinds of needs.  I loaded the Spider-Nut into the indexer’s chuck and set up the indexer to allow me to stop at 90° positions and locked the indexer into my mill’s vice.

An indexing head and mill will be most helpful. This is a shop-made unit.

After centering the part on my Y axis, I used a 0.250” solid carbide end mill at 3000 RPM and 0.020” DOC and 10 IPM to make the slots in the X axis direction.  I cut to a final depth of 0.125” for each slot.  Once complete I reset the Z axis and indexed the part another 90 degrees and repeated this process.  Lock your indexer down well when cutting.  This is steel and the cutting forces can get pretty high.  My failure to lock it down well enough cost me an end mill and left some decorative knurling around the rear of the Spider-Nut.

The slots could also be done with a shaper, or a broach of some kind.  The main thing is you want the slots to allow for tightening and removing the nut with a spanner wrench just like the existing jam nuts on the lathe.  A mill and indexer are but one way to skin this cat.  Once finished cutting I used a file to clean up the edges and knock down the sharp corners.

Next I drilled and tapped my holes for the spider screws using the same index positions as the slots.  I had positioned the part such that I could drill between the jaws of the indexer’s 4 jaw chuck at each index position.  Before I drilled I plunged a 3/16” end mill a few thousandths to cut a small flat into the outside of the part to give the tap-drill a place to start without wandering too badly.  I tapped using my mill and a spiral-point 1/4-20 HSS tap.  I tapped using power in low gear and at less than 100 RPM just letting the tap pull the quill down with it.

After that was complete I hit the inside of the bore with a round file to knock off the drilling burrs.  I also used a 90 degree counter sink to do the same for the outside of each hole around the part.

7.) Finish Work

Now it’s back to the lathe to put the finishing touches on the part.  This is mostly all cosmetic and can be adjusted to suit the taste of the person making it.  I loaded the part up and faced away the excess I left on the spider screw side of the Spider-Nut.  I left the length at 0.5” to allow for the 1/4-20 set screws and the heavy chamfer I planned for the spider side of the nut.

Next it’s time to rotate the compound to make the 45 degree chamfers.  I used 1/16” chamfers on the inside edges of the bores, flipping the part in the 3 jaw to get to both of them with the compound on the same setting.  I then reset the compound to do the 45 degree outside chamfers and did both sides of the spanner half of the part.  I now again flipped the part back around and re-chucked.  Last step was to cut the large 0.200” chamfer on the outside of the Spider half of the part.  Finally I used a little sand paper to clean up the appearance of the part.  The chamfers are all cosmetic so feel free to adjust those to your own taste.

Now I removed it from the chuck and threaded it onto the rear of the spindle to replace one of the spanner nuts.  It fit perfectly and extends only slightly from the rear of the G0602’s rear cover.  DO NOT OPERATE THE LATHE WITH THE REAR COVER CLOSED AND THE SPIDER SCREWS PROTRUDING FROM THE SPIDER-NUT!  Doing so may allow them to snag the cover while rotating and bad stuff is likely to result.  When using the Spider-Nut to support long work make sure the rear cover is open and propped out of the way.  When not in use, removing the screws completely would be prudent.

Finished Spider-Nut

Spider-Nut mounted

Spider Nut mounted and in use

Spider-Nut not used with cover closed

8.) Conclusion

This part fulfilled my goals for the project.  A rear spider that allowed me to support long limber work in the spindle that did not need be removed to operate the lathe normally nor be installed when needed with this design the spider is always ready to use when I need it and looks right at home on the lathe.  The rear cover is not interfered with when operating without the spider in use.  This not a difficult project but neither is it simple.  Without a mill and indexer a little ingenuity will be required to add the non-lathe features.

Here’s the link to the plans:

By Kyle Crane About the author

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It’s not that Norman has broken new ground and done something that has never been done before. There are after all lots of lathes with reverse capabilities. It’s also not like Norman’s solution is all that complex or difficult. But therein lies the genius of it.

A few months back a forum member by the name of rdfoster asked if anyone had come across a design for a reverse for the G0602. This prompted Norman to casually announced that he was going to build a reverse tumbler setup for his G0602, which is the same lathe that I and many others own. The G0602 is an extremely capable lathe, and as such is very popular among the hobby machining community. But it’s not without its limitations. Cutting left-hand threads is one of them. Norman set out to remedy this, and he did so within a matter of days, all out of his head, following no plans.

You’ve met guys like Norman. He reminds me of that guy we all know who can build a small backyard workshop or shed out of his head in a weekend … without plans. And when he’s done he has one stud and a half sheet of OSB left over. Anyway, enough praise for Norman and guys like him. Lets get on to the project.

I won’t try and re-write the steps that Norman took during the fabrication of his reverse tumbler, as I have nothing to add (having not built one myself yet). Instead I’ll direct you to the forum post where it all began.

Here’s a link to Norman’s original post:

Reverse for G0602

Here’s a link to a PDF file of Normans instructions along with a CAD version of Norman’s Plans drafted by Kevin Day (AKA Blame on the forum).

I’d also like to take a moment to thank Kevin for all his hard work on this project. Kevin volunteered to turn Norman’s White-Board sketches into a CAD file for everyone’s benefit. He spent more than a few hours drawing things up, and even patiently revised the plans multiple times at my request. Thank you Kevin for all your hard work!

If any of you readers end up making your own version of Norman’s reverse tumbler, please share pictures of your project and point out any design changes or improvements you might have made. I’m sure after just a few iterations someone will have a reverse setup that looks like it came from the factory! Share your pictures by posting them on Norman’s original forum post (the first link above).

So what’s Norman up to these days? Check out his speed reducer for the G0602:

G0602 Speed Reducer

Please feel free to share a link to this project, or any other you find on this site. Email a friend, post a link on another website or forum, etc. Please help spread the word about ProjectsInMetal.com and help us grow!

Skill Level: Intermediate to advanced
Type: Shop Manual
Projects: Several Supporting Tools and Procedures (Lathe)
Units: (in.)
Pages: 304 plus appendices

“The information is only a guide; the final word has yet to be written.” John L. Hinnant

Prophetic words from a book that was meant to be a shop manual. The Complete Guide to Precision Rifle Barrel Fitting by John L Hinnant is just that, a shop manual. As a matter of fact, the author encourages the reader to pull apart the binding, punch holes in the pages and place the book into a 3-ring binder. But don’t let the simple construction paper cover and lack of color illustrations and photos fool you. What this text lacks in “bling” it makes up for in substance!

Anyone considering placing a rifle barrel in a lathe must have this book. I cannot over emphasize the value of this book to a gunsmith considering rifle blueprinting as a service to offer customers. Amateur’s wishing to build their own rifles will fall in love with it immediately.
Broken down into the following sections, the manual guides the reader, step by step through the procedures of building the needed tools, fitting rifle barrels, blueprinting rifle actions, and chambering 22LRs with a special segment on Rugers. I listed the text as intermediate to advanced because it is obvious that some knowledge of lathe usage is assumed by the author. The drawings, while very adequate for anyone with at least some experience with a lathe, would leave the complete amateur wondering how the steady rest supports were suspended in space while holding the barrel. Obviously, Mr. Hinnant is gearing this to a reader with some prior knowledge of lathe operations.

Sections:
1. Accessory Tools for Fitting Rifle Barrels
a. Reamer Wrenches
b. Bolt Lug Lapping Tool
c. Receiver Facing Mandrel
d. Dial Indicator Tail Stock Fixture
e. Barrel Vises
f. Receiver Wrenches
2. Lathe Cutting Tools
3. Lathe Cutting Speeds and Feeds
4. Squaring the Receiver Face
5. The Barrel Turning &Fitting Procedure
a. Facing off the Center Holes
b. Drilling New Center Holes
c. Turning a Relief Cut on the Muzzle
d. The Basic Lathe Set-up
e. Turning the Breech O.D.
f. Marking the Breech and Thread Tenon Length
g. Turning the Thread Tenon Diameter
h. Turing the Thread Relief Groove
i. Facing the Thread Tenon to Length
j. Counter Boring the Breech Face
k. Shaping the Coned Breech
l. Reaming the Chamber
m. Threading the Thread Tenon
n. Determine the Correct Chamber Depth/Headspace
o. Finish Chamber Reaming and Head spacing
6. Chamber Throat Length
7. Crowning the Muzzle
8. Milling the Extractor Cut
9. Assembling the Barrel and Receiver
10. Fitting a Barrel to the Single Shot Action
11. Blueprinting a Rifle Action
12. A Blueprinting Update
13. Chambering for the Twenty-two Rimfire Cartridge
14. The Ruger Models 10/22 and 77/22

Mr. Hinnant offers several options for set-up, taking into consideration that not everyone’s lathe will accommodate a barrel between centers or through the spindle. Set-up processes are explained with emphasis on the pit-falls to beware of and drawing based orientation of information being relayed. Likewise procedures take into consideration some of the hazards involved with regard to what won’t work on certain rifles, such as a warning against over-lapping bolt lugs on certain case-hardened Mauser actions.

In closing, this book is written, printed, and presented by the author as a shop manual. It fills that role very adequately. It is a vast pool of information and reading it will be a joy for anyone who has ever dreamed of barreling their own rifle from scratch or turning that old deer rifle into a F-class trophy winner.

Reviewed by Dale Annis
About the author

To leave a comment join the forum discussion on this post

by Glenn W.

Material: Steel

Units: (in)

This Craftsman-style circle cutter is designed to be used in a standard Drill Press or Vertical Milling Machine only.

It is designed for cutting 1″ to 6″ diameter holes in sheet metal, brass, copper, plastic, wood, or other composite materials. You can also cut 1″ to 6″ diameter circular disks or wheels. This tool is only recommended for material thicknesses of 1/8″ or less.

Some examples of practical uses for this tool are:

• Cutting holes in automotive dash panels to fit around gauges.
• Cutting holes in sheet metal where hoses will pass through
• Cutting wheels for toys.
• Cutting round discs in aluminum for making fly-fishing reels.
• Practical uses are endless …

This tool is fully adjustable for cutting diameters from as small as approximately 1″ to as large as approximately 6″.

By simply grinding the proper angles and reliefs on standard 1/4″ HSS tool bits you can cut perfect holes or round discs, depending on the orientation of the tool bit cutting edge.

The attached set of drawings and assembly plans are based on a Sears Craftsman tool, model #25293 (pictured above). However, the design, dimensions, and components have been modified for improved performance and safety.

Proper cutting speeds, cutter relief angles, etc. will need to be established and adjusted according to the job at hand and the material being cut.

Important Notes:

• Speed of drill press or milling machine should NOT exceed 500 RPM when using this cutter.
• Always wear safety glasses when using this tool.
• Use of cutting oil or coolant will greatly improve cutter performance when cutting metals.
• Not recommended for materials thicker than 1/8″.

To leave a comment join the forum discussion on this post

Many of the pieces for this engine are easy to machine and require no explanation, but some are a bit more difficult. My intention here is to describe the more complicated pieces and the machining steps I used to complete them. My methods aren’t the only way to machine the engine, but if they worked for me, they should work for you as well. I’ll be documenting this project in several parts:

Part 1: The Cylinder
Part 2: The Piston, Valve, and Connecting Rod
Part 3: The Flywheel
Part 4: The Ball Bearing Support and Spirit Burner

So let’s get on with it.

Part 1: The Cylinder

Jan recommends using “pearlitic cast iron” or stainless steel for the cylinder, piston, and valve. I’d recommend trying to get cast iron if you’ve never worked with it before. It’s different than steel and very messy to turn, but I think that it’s properties lend itself well to the cylinder design. For one thing making the cylinder, piston, and valve from cast iron helps with lubrication because cast iron rubbing against cast iron is somewhat self-lubricating. With a flame eater engine you don’t want to use oil to lubricate the cylinder because it will eventually burn away and gum up the cylinder. Another benefit of cast iron is the fact that it was easy to cut the fins with a parting tool. The cast iron chips were short and broke away easily unlike steel, which often produces long springy chips that bind in between the two halves of the piece being parted off (or in this case between the fins).  In my opinion it would have been a little more difficult and taken more time to cut the fins in a steel cylinder. Whichever you choose, be sure to make all three parts out of the same material. If you make the valve and piston out of steel and the cylinder out of cast iron (or vice versa) they won’t expand and contract at the same rate leading to either a sloppy fit, or too tight a fit once the engine heats up during use.

Step 1a: Turn OD

Center drill the cylinder and support with a live center (or lubricated dead center). Note: other than lubricating the dead center, don’t use lubricant when cutting cast iron – it should be turned dry. Turn part to the desired OD but leave .001 extra to polish to size. I used 400, 800, 1200, and finally 2000 grit sand paper to get literally a mirror finish on the cylinder. Note: the picture below shows the part unsupported and with the cylinder hole already bored, you’ll be boring the hole next.

Step 1b: Drill/Bore/Ream ID

Remove the center drill and drill the hole to within .010 of final size, then bore to .001 or .002 of final size, and ream to final size (ream if you’ve got a reamer, if not you can always lap the cylinder instead). I drilled the hole in stages, about 1″ deep at a time. I drilled a .250 hole an inch deep, then I swapped the .250 for a .500 drill and pecked until that drill bottomed out at about an inch deep. Then I’d go back to the .250 drill and make the hole deeper by another inch or so. Drilling the hole in steps like this is safer than trying to drill the hole to depth in one plunge. If I tried to drill 3″ deep with a .250 drill bit the bit would likely break. But it’s fine in one inch increments. Remember to “peck” with the drill – plunge .050 or so and then retract the drill to clear away chips – then plunge another .050. The larger the bit the deeper you can plunge without clearing chips, but watch carefully. If chips stop coming out of the hole on their own they are building up inside and will eventually bind the drill causing it to spin in the chuck or break. Avoid that.

Once you’ve got the cylinder drilled out to within .010 of the final size for the entire depth of the cylinder, move on to boring. Boring will ensure that the hole is concentric and uniform in diameter across the entire depth. Take very light cuts with a quality boring bar. If you’ve got a reamer of the proper size use it. But don’t ream more than .001 or .002 and try to ream the hole all at once in one continuous plunge while turing the work at a slow speed. Don’t ream the hole multiple times or the hole will likely turn out oversized. Don’t ever run the lathe in reverse with a reamer in place – you’ll dull or chip the flutes on the reamer.

If you don’t have a reamer or your hole ends up slightly under or over the desired size, don’t worry. You’ll be turning the piston and valve to fit.

Step 2: Cut the Fins

This step really spooked me. So much so that I set the part aside for weeks avoiding this step. Don’t let it scare you -especially if you’re using cast iron. It’s not as bad as parting off because you’re not plunging the parting tool all the way to the center of the part. I turned the part at a fairly fast RPM, 500 maybe? I can’t remember for sure. And I plunged the parting tool very slowly into the part to the desired depth. I made sure that the parting tool didn’t stick out any further than it had to for clearance – thus avoiding unnecessary overhang. I used a dial indicator with a mag base to accurately space the fins. Be sure to support the part with a center to help with chatter. Once you’ve got the fins cut, part off the cylinder leaving an extra .005 or so of length so that you can face and polish the newly parted end.

Step 3: Mill the Large Flat

Support the part in the mill vise and mill the flat. I have a horizontal mill, so I’m using a vise within a vise to support the part parallel to the end mill. Remember to use some sort of packing. Aluminum shim or card stock (I’m using an old business card). Take light cuts of .005 to .010 – deeper if you’re using a larger end mill and have a more robust mill. But be careful not to put to much cutting force on the part – it could cause it to shift or rotate spoiling all your work. Take your time.

I used the knee to keep track of the depth of the flat, but you can also use a multi-anvil micrometer (with the cylindrical anvil inserted) to measure from the ID of the hole to the flat to double check your knee measurements.

Step 4: Cut the Two Small Flats

This step is pretty simple, but I thought it was worth mentioning the use of a square to ensure that the two small flats are at a 90 degree angle to the larger flat. The angle isn’t critical (89 or 91 would be fine) but it’s nice to have a way to get it very close.

Here’s a finished flat.

Step 5: Drill and Tap for 2x Cylinder Supports

You want to be very careful on this step not to drill too deep. If you drill into the cylinder bore, you’ve scrapped your part. One way to make sure you don’t drill too deeply is to use the knee on your mill. I’ll show you another method using a drill press and a plug gage.

Position the part so that the drill bit is just touching the surface of the flat (note: you should have already center drilled). Then use a plug gage with a diameter that matches the depth of hole you wish to drill. Position the plug gage between the nut and the stop on your drill press depth stop and turn the nut until it’s contacting the plug gage. Then remove the plug gage. Now when you plunge your hole the nut will contact the stop after plunging to the depth set by the plug gage. Now tap your holes using a plug and bottoming tap.

Step 6: Mill the Intake Slot

This is pretty self explanatory, but I would recommend using an undersized end mill. If you use a 3mm end mill from the start, your slot will be 3mm+ and ugly. I used a 7/64″ end mill and plunged the slot to depth and length using multiple passes along the centerline of the slot. Then I widened the slot from .109 to the 3mm (.118) width by taking a bit off of the top and bottom of the slot.

Here’s another view.

Step 7: Drill for the Valve Push Rod

This was another step that concerned me – but drilling the 4mm hole turned out to be a piece of cake because each gap between fins allowed for chip clearance. I could have plunged the entire hole all at once, but I didn’t.

Step 8: Bronze Bushings

Making the bronze bushings was easy. Turn the speed up to a fast speed appropriate for bronze of that diameter and use a sharp tool. I was able to turn the bushings unsupported using light cuts (.005) and a sharp tangential tool holder from Eccentric Engineering. I’ve worked with bronze in the past when I replaced the bearings on my Atlas mill and the bronze chipped away in dusty flakes. With my new tangential tool holder the bronze made long spiral chips and had a beautiful finish. Coincidence? No. Get yourself a tangential tool holder. You won’t regret it.

Once you’ve turned the OD and drilled the ID, part the bushins off and press them in. They are small enough to be pressed with a quality vise. However, as a general rule I’d recommend you avoid using your vise as an arbor press. It’s a bad habit that can lead to a busted vise casting. Add an arbor press to your tool list. Harbor Freight sells them and they are much cheaper than a new AngLock-style vise.

Step 9: Fixing a Rookie Mistake

By now you should be finished with your cylinder. But I wasn’t. I mentioned at the beginning of this post that I’ve been working on this project for over a year now and I turned most of the parts that I could make on the lathe months ago. Unfortunately I substituted a 5M thread for a 4M thread on the cylinder supports and completely forgot. Months later when it came time to make the cylinder I went ahead and tapped the holes for a 5m thread, not a 4m. The result can be seen below. Obviously the support legs didn’t fit. I fixed them by re-chucking them and drilling them out for a 5m set screw – which I inserted upside down and secured with lock-tite. It’s upside down because the support has a hole all the way through – so I’d have access to the set screw using a hex wrench if I ever needed a little extra force to remove the support legs from the cylinder.

I’m including my mistake so that you guys can learn from it.

Lesson learned: Never change a part without making a change to all mating parts on the blueprints.

But I also thought it would be an opportunity to show you that some parts can be made without using a die. I could have easily made these supports using a 5m tap and set screw from the start – totally avoiding the need to purchase a 5m die. Since I normally work in inches and not mm, this would have saved me a few dollars. I have a complete set of taps and dies up to 1″, but up until this project I didn’t own any metric taps or dies. So this little engine has actually been a bit more expensive than I had hoped. But that’s ok. And of course you can usually use the nearest inch equivalent when tapping holes of a non-critical dimension. I just didn’t want to. I wanted to use this project as a chance to practice working with metric measurements.

Well, that’s about it for the cylinder. Next I’ll be documenting the steps for making the piston, valve, and connecting rod.

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For example, 0.875 divided by .060 equals how many rotations of the tailstock handle? It’s ridiculous to me that I need to do math (even simple math) just to drill a hole to a depth of 0.875. If my tailstock had 100 graduations things would be a lot easier … but it doesn’t. It has 60.

60? Really?

Now, about the backlash. I know what you’re thinking. Who cares about backlash in a tailstock? Apparently I do. My psychiatrist and I are working on that …

And yes I realize that 99.9% of the time the depth of a hole isn’t a critical dimension – but I’d still wanted more control and accuracy out of my tailstock.

At least, that was the case. But no longer! With the exception of the short throw all the other issues with my tailstock were resolved with one simple stop that you can easily make in an evening.

This project is very simple. The only thing that I can see tripping someone up is remembering to create thread relief for the cap screw. When you drill and tap for the 1/4-20 cap screw, you’ll want to also drill a .250 thread relief  to the halfway point (where the slitting saw will eventually cut) so that the dial stop is only threaded on one of the two sides. If you thread both sides the two sides won’t draw together when you tighten the cap screw.

I didn’t draw up plans because of the simplicity of the project and because each person will need to scale the project up or down to fit the size of their lathe. I did, however, make a build video. Let me know what you think!

If you make your own please post pictures on the forum.

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The aluminum body of the die holder holds the die perpendicular to the axis of the spindle rotation and rotates freely around a steel shaft firmly inserted into the tailstock. This ensures that your part is threaded perfectly.

Here’s a picture of the Die Holder with a 1.5″ die inserted:

Here’s a picture of the Die Holder flipped 180 degrees with a 1″ die inserted:

I got the idea from Steve Bedair’s Die Holder and I adapted it to look similar to a smaller die holder sold here by LittleMachineShop.com.

I created the plans myself using Autodesk Inventor. It was my first attempt using the software, and my first time drawing up plans for the machine trade – so if there are any errors please let me know and I’ll do my best to fix them.

Here are the plans (in PDF format):

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