Making an ER16 collet holder

Long long ago I bought a set of collets to accurately hold smallish diameter metal for machining. The Unimat resisted my attempts at Plan A, adapting an existing collet chuck. The problem is to get the addition exactly concentric to the lathe spindle. The one I built had a runout (wobble) of .006” which is way too much for precision work.

For the Taig I decided to make on from scratch. This should result in one that is exactly concentric since it is built on the actual machine it will be used on. You can buy one for $23 but this way I learn some more skills, which will come on handy later.IMGW1149

Starting with a blank arbor ($3.60 at Lee Valley), I cut one end short and then turned it down to 22mm, the size of the collet nut. A 9mm hole through the center, tapped for M10x1.5 metric. Using a bolt (with head cut off) I then made a threading jig. As you turn the spindle the bolt threads into the part, dragging the tailstock and carriage along. The cutting bit cuts the thread, exactly mirroring the one on the bolt. No, I didn’t invent this method but it is gracefully simple. The lathe chuck is turned by hand giving total control over the operation. After about 10-12 passes, we have an M22x1.5 thread!

The overall dimensions of this one are: 1.5″ length overall, the M22 thread is 13mm long. The inside hole is bored out to 12.5mm before cutting the taper (happened to be the largest stub drill I have). This is I think overall shorter that the Taig and A2Z ones . You could go a bit shorter yet without the collet bottoming on the lathe spindle.

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Next is the inside taper, 15 degrees total. I set the compound rest as close to 8 degree as possible and cut most of the taper. When I got close to the correct size I used a collet with an rod in it to test for wobble. The collet should just go in, no wobble. Adjusting the angle slightly and light cuts resulted in an accurate taper.

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Two short cuts in the milling attachment to add wrench flats and we are done. All told maybe 2 hours work. The chuck itself has no detectable runout, a rod sticking out about an inch has .0005 runout. Should be good enough for most work Smile

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Replacement locking handles

The SHCS used to tighten various parts of the lathe are great if you only need to do that once in a while. Now that I have a die holder, replacing those is the next project. Most implementations of the handles involves knurling but I find the t-bar style more effective, esp. when you have oily hands.

Some 8mm drill rod (silver steel), 1/8” shafting from surplus mechanical aircraft instruments and a 10-32 die result in these:

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These are a joy to use, the T-bar gives very fine control over the torque you apply without requiring a lot of finger pressure. I can lock the cross slide, carriage stop and the 2 tail stock features easily without hunting for a hex key.

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Chips, contain yourself

Machining in a condo/apartment brings with it some restrictions. One is controlling chips that like to fly everywhere, the other is noise and vibration. Having done some of the work so far in the hobby room 11 floors down, I would prefer to do as much work at home.

Reusing the Plexiglas from another project, I built a folding lid and support. An additional shield mounts to the carriage and lastly one on the head stock to keep stuff from going to the left. Drilling brackets is made easier with the milling attachment, excellent control of position etc.

In practice the shields do quite well. Sometimes swarf/chips still come out the front so I will no doubt do a Mk 2 version later on.IMGW1105

With that under control, I moved to the vibration issue. Noise travels in interesting ways in concrete buildings, our condo is no exception. Keeping the noise down keeps the cats happy as well.

I made silicone isolation bumpers from bath tub sealer. The mold is part of a roll-on deodorant cap. Fill half way with sealant, smooth out and let it cure for a few hours (this type of silicone air cures, nothing much seems to speed up the process). Fill to top of mold with more sealant, smooth out and let it all cure for 2 days. 3 of these do a wonderful job! 2 go on the LH side of the mounting board, one in middle on RH side. (RH side does not have a lot of weight on it)IMGW1109

The end result of today’s efforts is a tidier work environment that I can use even in the evenings.

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Cross slide DRO

I did some planning for the modifications and additions I want/need to make. One of those involves turning down 8mm drill rod to .1562 to tap as 10-32 thread. Rather than cut, stop to measure, guess how much more to go, cut, etc. I wanted to mount a digital gauge on the cross slide. This would let me cut until I reached a reading of half the required diameter.

Inspiration came from Start Model Engineering. I already had the gauge as I previously built the same thing for the Unimat.

Having the slitting saw made it easy to cut some ‘mystery’ aluminum from Home Depot to size. Mounting is by super-glue for now until I am sure where to drill holes for more permanent mounting.

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Slitting saw arbor

Cutting metal by hand is tiring and doing it accurately is difficult. Next up is a slitting saw arbor. This lets me use a metal cutting blade to accurately cut bits of metal, plastic and even wood.

Taig sells blank saw arbors, you just need to turn the end down to fit your blade. My blades have a 13mm hole so that is what got cut. No problem cutting stuff now! The big stuff of course still gets done on the 4×6 horizontal band-saw .

My saw blades come from CTC Tools, a great online shop for quality tools.IMGW1101

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