The G0602 has proved to be a very popular lathe and has gathered a large following. The lathe is one of the most popular once you go beyond the mini-lathe class of equipment. With so many followers it is no wonder that a large number of improvements have been developed by the users. Earlier I attempted to combine some of the more popular changes that have been submitted to this and other blog sites and listed them here:
But since then there are even more interesting developments. One metalworking project I have been working on and thought I would share is a retractable cross slide device. Originally this project was intended to be one of a three part series that covered a retractable cross slide, a replacement for the compound slide, and a threading tool holder with a micrometer feed. I was not happy with the threading tool holder so I am redesigning it and with a little luck I will be able to post that project at a later date. In the meantime, take a close look at this project. While it was designed with the G0602 in mind, I am sure it will work equally well on other bench-top lathes by making some minor changes.
Some years ago I came across several very useful tools designed by the late George Thomas these were outlined in the very popular book “The Model Engineers Workshop Manual”. A tool that is one of my favorites and one that I use on a regular basis is the retracting threading tool holder shown in the photo below. Using this tool greatly simplifies the threading process.
This tool allows the user to retract the tool bit after each pass. So as you approach the end of the thread a flick of the lever retracts the tool bit about 0.156”, enough to clear the threads so that the cross slide feed does not have to be touched for the reverse trip to the thread starting point. This tool greatly improves the threading process by simplifying the actions needed, eliminating the risk of forgetting cross slide setting.
From time to time though, the portion of the tool that extends to the left of the tool bit (the handle and actuator portion) can interfere with the lathe chuck or the work piece. I have wrestled with how to solve this problem and I believe I have developed a very good solution that has worked well for me.
Some of the more expensive lathes have a retraction mechanism that when activated retracts the tool bit from the work. You can have this same convenience on your G0602 with a modest amount of effort. This is a good weekend project and should be on your “A” list of future improvements.
Some thoughts on threading:
Threading is not something that most hobbyists look forward to doing. With a little forethought (and some practice) threading is no more difficult than other lathe operations. Properly cut threads can make a project really stand out. The ability to cut threads also gives the builder a larger range of options when tackling a project. For a lubricant I use Moly-Dee, this is my benchmark for cutting oils. This works well on 1018 which is the most common material used by most hobbyists. I dispense it with a small plastic squeeze bottle, a pint will last a long time.
A retractable tool, either by using a retractable tool holder or retractable slide, means that once I engage the half nuts I never disengage until the thread is complete. I reverse the motor to traverse back to the starting point. This in turn means that I can turn metric and inch using the same process. Retracting the tool greatly eases the threading process. Using the Fwd/Stop/Rev switch, the compound slide feed and the retraction lever are all you need to thread metric or inch. You do not need to deal with tool retraction by using the cross slide or syncing the tool position by using the thread dial indicator.
Recently I have come across a threading tool made by Mesa Tool (no affiliation), this tool uses carbide inserts. I personally like carbide and use it to a great extent on the lathe and the mill. The inserts that Mesa use are compact allowing work in very tight places. The threading bar can be used for internal and external threading. And, in my opinion can be used for right hand or left hand threads due to its zero top rake. Based upon my best visual examination the only difference between their right and left hand inserts is the chamfer for the mounting screw. Buy the standard left hand threading tool and you will be very a happy with the results. The price is $34 which includes two inserts, one of the few remaining bargains in the tool world.
The G0602 retracting cross slide:
Photo #3 shows a modification to the G0602 cross slide bearing carrier which turns it into a retractable cross slide. The ball handle mounted underneath the bearing housing retracts the tool bit about 0.187” with a flip of the finger, enough to clear all but the coarsest threads. This is also a handy item to use on finish cuts. When you reach the end and want to move the carriage back to the beginning the retraction of the tool will ensure no tool marks are left on the work.
Constructing this unit is not complicated but does require that you maintain close tolerances on several key components. The original lead screw and nut are used so the dimensions of the bearing carrier and housing are limited by the dimensions of the lead screw. If you made a new lead screw as part of the “Acetal nut project” then you can change the dimensions of the lead screw to accommodate changes you may want to make to this unit, but of coarse that involves making a new lead screw.
Find the acetal nut project here:
The unit pictured above is using a lead screw I made to correct the thread error of the original unit but the dimensions of the bearing shaft are the same as the original.
The ball handle is shown in the closed position, the position you would normally use while turning or threading. The ball handle rotates through ninety degrees to retract the cross slide a distance of about 0.187 (3/16”), this distance is variable by altering some of the dimensions during the construction. When in the closed position a spring loaded detent keeps the handle from moving. The motion is smooth and crisp, the repeatability is excellent. The “over center” cam action presses the bearing carrier up against a stop ensuring a rigid and sturdy positioning of the cross slide assembly. All of the materials used are 12L14 or 1018 steel.
One cautionary note prior to starting – I have no assurances that all 10 x 22 lathes share the same exact dimensions. As you fabricate various pieces that are dependent upon the specific dimensions of your lathe be sure to double check them. Several key areas are the diameter of the lead screw bearings, the distance of the bearing carrier mounting bolts, the center of the lead screw nut, and of course the length of the original lead screw bearing carrier.
We start by making the bearing carrier which is a steel slide through which passes the lead screw with the bearings on both ends. The bearing carrier slides in the bearing carrier housing when the lever is moved thus positioning the cross slide. With a piece of 1.000” inch steel rod take a cleanup cut of 0.005-0.016” (the exact amount is not critical) leaving a clean smooth surface. Use some emery cloth if needed to improve the surface. Through drill a 0.375” hole the length of the finished piece which is 2.540”. The diameter of this hole needs to be large enough so that bearings portion of the lead screw passes through easily without any drag or binding. To achieve this diameter and ensure that the hole is parallel with the outer surfaces I finished enlarging the hole using a boring bar. The finished diameter of the hole in my carrier was 0.406″, yours may be slightly more or less depending on what is needed to clear the lead screw shaft.
Note: you’ll need to single-click the following diagrams TWICE to see them in full screen and/or print them.
Next mill the flat on the bearing carrier per the dimensions in diagram #1 then set the unit aside.
Bearing carrier body:
The next step is to turn the housing. For this you need a piece of steel at least 2.250” in diameter and 3.100” inches in length. This piece can be machined one end at a time thus saving you from wasting a stub piece. Perform the final bore after the piece is positioned for the final cut. Use brass shims to protect the finish during the second cut. When boring use the bearing carrier as your gauge, you want a nice slip fit.
The flats shown on the bearing carrier body will be milled in a later step.
The slider needs to be a good fit into the slot milled in the bearing carrier. Start by turning a 1.000” rod down to the diameter of the bearing carrier for a distance of 0.600”. Prior to removing the piece from the lathe use a cut off tool to turn a groove that will result in an end piece that is 0.500” in width and about 0.300” deep. This piece can be slightly longer and then trimmed later using the mill. This dimension is what will determine the fit of the slider into the flat milled in the bearing carrier. Next mill a flat 0.075” deep as shown in the following photo, then drill a 0.1875” hole as shown in diagram #4. The final step is to saw off the slider piece using a slitting saw in the mill. After examining diagram #4 you may feel that is is more practical to fabricate this piece using flat stock, feel free to use either method.
The next step is to fabricate the flange, this is the piece that holds the assembly to the lathe apron using the existing 8mm socket head screws. This is another piece where you should feel free to deviate from this plan. I used a slice from a 3.000” 12L14 rod, not everyone will have this available. The end result is a flange that is about 0.375” thick (it can be a little more or a little less) which means you could decide to use a piece of flat stock that is close to the correct thickness, or perhaps thicker and then surface mill the material to the correct thickness. Diagram #5 shows the needed dimensions.
If you are using a lathe to make this piece complete the facing of both sides then turn the recesses for the bearing carrier and bearing carrier housing. The housing should be a close fit in the recess. The flat shown above will be milled in a later step as will the placement of the holes for the mounting screws.
The next steps are to mill a flat on the housing body and then drill, tap and countersink the flange screws. The screws used for this and several other applications are 10 x 32 socket head screws with the head turn down to 0.250” in diameter. Two of these modified screws are shown in photo #11. To turn these screws I used a ER32 collet but you could perform the same operation a number of other ways such as drilling a tapping a short piece of rod and then chucking that in the lathe. The screw on the right has a pin turned on the end and is used as the retainer screw.
Prior to drilling and tapping the flange hold down screws we need to mill a flat on the bearing carrier housing. Mill a flat 0.085” deep on the larger part of the housing, this will be on the lower side of the finished unit and will be used as a reference point to ensure that things square and aligned. After milling this flat, mount the housing in the mill vise and place the flange on top of the smaller end. See photo #12 for the correct orientation. Diagrams 2 and 3 will help clarify the position of these flats.
To drill, tap, and countersink these holes I used the bolt hole function that is built in to the DRO. If you do not have this capability then the next diagram will provide the needed “X” and “Y” coordinates for these holes. I drilled the tap hole first (total depth of 0.600”), then I drill the clearance hole to a depth that just cleared the flange body but only touched the bearing housing. I then recessed the countersink hole to a depth of 0.130” after which I tapped the hole. A word about socket head screws is needed, the head size, socket size and head height can vary depending upon the vendor so you may need to shop around. The screws I used had an original head diameter of 0.313” and a height of 0.130”, this is the most common size. The height was left as is but the diameter was turned down to 0.250” and thus used a 0.250” end mill to counter sink the hole. See diagram #6 for specific details.
Once the drilling, tapping and countersinking is complete attach the flange using the modified screws and place the flange and housing in position for milling the top flat on the housing and flange. As shown in the next photo I used a slitting saw to remove a large portion of the flange thus saving some milling time. Next mill the flat on the top of the smaller end of the housing. The depth of this cut is determined by the height of your cross slide ways, you may want to use your existing cross slide bearing carrier as a guide. In my case the cut was 0.200” leaving a thickness of about 0.090” on the top of the housing.
Once you have completed milling the flat the next step is to remove any excess material on the ears. The remaining material, the ears, will block the cross slide table and chip shield if not removed. I chose to mill off the excess to the shape of the bearing housing by using a rotary table. Another method would be to step mill the area and trim the corners by milling them at a 45 degree angle, another area of choice for the builder.
Eccentric bushing and actuator:
At a later point in this project we will add a limit stop to the bearing carrier and housing the purpose of which is to provide a rigid position for the carrier when in the home position. To accommodate any small variations in the dimensions of the various components and to deal with any future wear the actuator shaft is carried in an eccentric bushing which can be adjusted to null out these differences. Take a look at the next photo to obtain an understanding of how these components work.
At a later point we will bore a hole on the flat located on the large end of the bearing carrier housing, into which the bushing will fit. The actuator shaft then fits into the bushing and the actuator pin engages the hole in the bearing carrier slider. Rotating this shaft is what moves the bearing carrier and thus the cross slide in and out.
Diagrams #7 and #8 will give you the dimensions for the eccentric bushing. Turn the outside of the bushing to size then use 0.035” of shim stock to offset the bushing then drill and bore the hole to 0.5625”. A good finish will help in adjusting and using the actuator, polish with emery cloth.
Once the bushing is complete start on the actuator shaft, diagram #9 will give the dimensions needed.
Finish machining the housing:
There are a number of holes that must be drilled and in some cases tapped so it is time to start that task. The dimensions for most of these holes is exacting so take your time, by now you have considerable effort invested machining the housing we do not want to end up scraping it.
Start by drilling and boring the hole that the eccentric bushing will fit into. Diagram #10 will provide the dimensions. Place the housing in your milling vise and use parallels to position the housing so that it is square with the flat side of the large end up. The parallels are placed under the flat that we milled on the top of the smaller end of the housing, this will ensure that the housing is parallel with the mill vise base.
You can step drill until you are close to the final size which should be 0.750”, use your eccentric bushing as a guide since you are looking for a close fit. Once the hole is complete bore the recess for the lip of the bushing. While you have the housing in the mill vise you can drill two more holes, one for the detent spring and guide, the other for the handle limit pin. I used an eighth inch (0.125″x0.375″) dowel pin for the limit pin but if you do not have a dowel pin of this size you can use an eighth inch steel pin. The pin is a press fit, if you use mild steel for the pin you may want to drill the hole to 0.125” and secure the pin with Loctite.
The hole on the side is for the retainer screw which is one our modified 10 x32 screws with threads on the end turned off to give a smooth pin. When you reposition the housing for this operation place the bushing in the hole and rotate it such that the thickest wall of the bushing is centered on the hole position, photo #20 will illustrate this. I scribed a line indicating the thickest point to help me during alignment. Start by milling a counter bore using a 1/4″ end mill or slot drill. Then tap drill and allow the drill to go through the housing and through the bushing. The bushing hole will provide a guide when we slot the eccentric bushing and groove the actuator shaft. If you tap through the bushing it will not matter, you may either remove the bushing prior to tapping or tap through.
The hole on the front edge of the housing is for a set screw that will force a cotter up against the bushing to keep it from rotating. Drill through the housing until the drill bit passes into bore and stop just short of the retainer screw hole. Tap the first 0.375” but not the rest. You will use a short ¼” x 20 set screw to force the cotter against the bushing. To make this cotter measure the hole depth, subtract the length of the set screw and cut a piece 3/16” brass rod to this length, you can obtain this rod in short pieces at most hobby stores. Place the brass into the hole and run the set screw in to hold it. To shape the brass cotter to a shape close to that of the bushing I used a Dremel tool with a small sanding drum and carefully hand ground the piece. You do not want to remove too much material, leave some material so that it stands proud of the bushing bore. To insert the bushing back out the set screw and the cotter, insert the bushing and then tighten the set screw so that the cotter just touches the bushing.
Two tasks remain before we can put all this together for final test and adjustment. The first is to mill a slot 0.125” wide in the eccentric bushing; the retainer screw will fit through this slot. I used a rotary table to rotate the part as I milled. If you do not access to a table a straight mill slot will work just as well. On the rotary table I milled through a 30 degree arc. A straight slot of about 0.312 – 0.375 should work. As a guide use the hole that was drilled through the bushing when we drilled and tapped the retainer hole.
Next place the actuator shaft in the lathe and mount your cutoff tool. We will turn a groove to a depth of 0.125”, slip the eccentric bushing over the actuator shaft and use the milled slot as a guide. Depending upon the width of you cutoff tool blade you may need to make more than one pass to achieve the needed 0.130” wide groove.
Final assembly and testing:
Start the assembly by inserting the eccentric bushing, then the bearing carrier and slider plate. Align them such that you can insert the actuator shaft so that the pin drops into the hole on the slider plate. Rotate the shaft clockwise until it stops, remove the shaft and see if the slider plate hole is at top dead center. If not it is probably because a portion of the slider plate needs to be milled, filed or ground away. Repeat this until the hole ends up a few thousands past top dead center, this is a judgment call unless you have a lot of measuring equipment. With some practice and a glass you will soon get it within a few thousands.
Once you are comfortable with the action of the actuator and the position of the slider plate when it is in the “home” position place the assembly in the milling vise as shown in photo #25.
After drilling, countersinking and tapping the hole remove the clamp and remove the bearing carrier. Next mill a ¼” slot 0.1875” long (measuring center to center), the depth must be all the way through the housing so you will probably want to do this in several passes. The length of this slot controls the arc the handle will pass through when opening the unit and the overall length of withdrawal. A 0.1875” slot will result in a 90 degree handle arc from closed to open. If you feel a larger opening is need this can be accomplished at a later time or now. As the slot gets longer the arc of the handle increases up to a maximum of 180 degrees and an opening of about 0.375”. I have found that 0.1875 is more than adequate.
Using a piece of 1.500” inch rod we will make the handle collar. Using the lathe bore the rod to 0.500”, clean up and polish the outside, add a small chamfer to one end and then part the piece off. Using the mill, with a slitting saw cut through one side. Next mill the recess, drill and tap a 10 x24 socket head screw. This will allow us to position the handle at the angle we desire prior to milling the limit groove. See diagram 11 for more details.
With the prototype unit that I originally built I experimented with the handle position. I tried it with the handle on top and on both sides. I found that mounting the handle on the bottom worked the best since this location provided most room for the handle to move through. On the top and sides there were conflicts with the compound slide and apron wheel. You can construct a handle many different ways, I made a ball end handle for the final unit. The prototype had a 3/8” bolt for a handle, determine your choice and then drill and tap the collar to accept your handle. Once this is done mount the collar loosely on the shaft and install the retraction unit on the lathe (this is a temporary install) and then move the handle to the position you would like it in when the unit is in the “home” position. Using a Sharpie or other marker place a mark at the location where the limit pin will be located.
Next, mill a 0.250 groove for the limit pin travel in when the handle is moved from home to open and back. Mill this groove through a 90 degree arc. You should install your limit pin at this point and measure the height above the housing and mill your groove depth accordingly.
Photo #28 will give you an idea of what I used for a detent, the spring is about ½” in length and ¼” in diameter. The brass detent was turned from a short piece of ¼” brass rod so that it fit inside the spring. The top was rounded with a file while chucked in the lathe.
Remove the retraction unit from the lathe and disassemble it, time to lubricate the parts and put it back together. I used white lithium based grease and found that this worked quite well, of course you could also use oil. If oil is your choice then I would drill several oil ports to facilitate lubrication from time to time. Lube and assemble the slider, bearing carrier, eccentric bushing and actuator shaft. Install the limit screw into the hole in the bearing carrier. Using either your finger or a “C” clamp position the bearing carrier so that it is up against the limit screw in the home position. Next, rotate the eccentric bushing in the direction that will move the actuator shaft toward the limit screw. When you reach a point of resistance tighten down the set screw against the cotter. The needed rotation of the bushing should be very little if any. Once that is complete withdraw the actuator shaft and recheck the position of the slider hole to make sure we are at or slightly past top dead center. Replace the actuator shaft and install the retainer screw. Lube the detent spring and detent and install the detent pieces and the handle. Test to make sure everything moving smoothly then using your marker carefully mark the home location of the detent. Remove the handle collar and drill a shallow 3/16” depression into the underside of the collar where the detent will reside when in the home position.
It is probably a good time to clean and re-lube your lead screw bearings. Next reassemble all of the pieces and install them in the lathe. Once you become accustomed to using a retractor, lathes without them will seem as though they are missing a critical function. The G0602 can become a formidable bench lathe when equipped with the changes that have been posted on ProjectsInMetal.com, I encourage you to peruse them and implement those that will assist you in the type work you do.
As always if you have comments or questions about this project do not hesitate to contact me either through the forum or private message.