Here’s a nice weekend metalworking project for you, an adjustable tailstock for a 5c collet indexer!
I have noticed in several articles that there seems to be a lot of interest in an adjustable tailstock for a 5c Collet Indexer. Over the years I have accumulated three of these handy gizmos and not a one of them came with a tailstock. So what gives? Having never been accused of being non resourceful … I decided to make my own. Making my own adjustable tailstock turned out to be a rather simple straight forward project with only the center piece being in anyway critical as to dimensioning and tolerance. I came up with several design ideas, but I am happy with the results of this one.
First I must confess I am not much of a welder. I call myself more of a “sticker together-er” than a true welder. My welding projects do usually stay together and are almost always functional but they seldom very pretty. Thank God for grinders! In our line of work pretty counts. Usually a whole lot. The next big evil to rear its ugly head is warpage. My Dad’s brother Karl was one hell of a mechanic and welder. He worked on logging equipment and large trucks and even boasts plying the Snake river to the Columbia and Portland Oregon and finally the world. This man knew how to set and tack his metal so the welding drew the pieces together, and stayed flat! What a talent.
Myself, I am a bolt-er. Cut your pieces as straight and square as possible then assemble with good bolts or cap screws. If nothing else it is easier to disassemble to fix mistakes or missteps in construction sequence. Hence you can see in the picture below the bottom of the tailstock with the cap screws holding the uprights in position. The notches of course are for bolting to the table and the longitudinal groove is for a block for instant alignment to the mill table via the table slots. I usually remove them as every machine I have seems to have different slot dimensions so I have to keep a little box around full of different blocks for different tools. The only standard is the slot on the base of the tool at 5/8″ wide. If the slots on my tools aren’t that size when I get ’em, they will be shortly!
The body material, base, and uprights are 1/2″ plate. The rest of the dimensions you probably need to figure for your application. The side slots are milled to fit 5/16″ grade 8 bolts. The slots on the back side were oversized (shown in the disassembled picture below) so that the head of the bolt would be held securely in place without rotating. That way only one wrench (to loosen/tighten the nuts) would be necessary for adjustment. These slots were calculated to be centered vertically when using the intended original collet fixture. However, I provided an inch of play above and below centerline to hopefully allow for future unknowns. The center shaft support can also be flipped upside down to gain a little more height. The square piece supporting the center is a piece of 1″ x 1 1/2″ x 6″ stock. A 3/4″ hole was drilled and reamed into the bottom half vertically. At the rear portion a 1/2″ hole was drilled and tapped to accomodate a piece of 1/2″ all-thread, which is secured to the center shaft support using LocTite. The other end of the threaded rod is for the adjustment knob to ride on. Please take the time to chase the all-thread or do whatever it takes to slick it up real well so the knob freely spins end to end. Doing so makes the whole thing more of a pleasure to use and believe me it will probably be spun a whole bunch in its life time. So make it easy on both you and the tailstock and I will sleep better.
Drill and tap the center shaft support for a #10 ball end set screw with jamb nut, This was added at the last moment to ensure the center does not rotate when in use. For some reason the shaft had a tendancy to want to twist or turn when the knob was turned. The ball end rides in a shallow groove along the axis of the center shaft. The end oposite the knob was split using a slitting saw to allow it to squeeze just enough to lock the center shaft. A 3/8″ – 24 NF socket head cap screw was incorporated for the lock.
The knob was turned from a piece of scrap 2 1/2″ round laying in the junk box. From a design standpoint the only two critical areas are the 1/2″ x 13 tapped hole for the all-thread and the groove that fits the slot on the center shaft. Other than that be creative and let your artistic juices flow. Just be sure to clean up and lubricate well so nothing rusts. Cut fillets, round corners, square corners, hollows, knurl it, bevel it and do a chamfer like no other. It’s your baby, show the world you skills and talents.
The final piece to machine is the center shaft. A 3/4″ diameter piece of silver steel was set in the lathe and a 60° center turned. Now the fun part! I have acquired two tool post grinders, a dinky small one and a real DuMore. Sad part is I don’t hardly use them as I often don’t really know when, where, or how they should be used. Now I know hydraulic cylinder shafts are ground to finish. Same for silver steel drill rod. In all my playing I have never ever came close to that kind of finish. I do much better with a long angle lathe file and emery paper. All the grinding articles I have found on the net are pretty lame also. But not the point here. I mounted the grinder, rechecked all angles and clearances, trued the stone with a diamond, then covered everything well with shop cloths. Then I fired that baby up and ground the center to a rather pretty finish if I do say so myself. Shallow cuts and slow turns on the compound did the trick this time. I asked a master machinist once how to calculate or allow for stone wear, his answer: “Don’t worry about it”. So until I know different, I won’t. The cross groove for the knob was cut and the longitudinal cut for the guide pin.
After knocking off some burrs and sharp edges, polishing here and sanding there, I applied a little paint there I declared it “DONE”. I had a project ready for it and it worked out quite well. Seems I am always grabbing 1/4″, 3/8″ or 1/2″ stock for something and when center drilled and supported you can mill the devil out of that shaft with no wobble or vibration. Pretty sweet!
Now you know what to do and how to do it. So get out in the shop and make the SWARF fly!
– Russ About the Author