I saw a 5C collet holder for a BXA QCTP and decided I wanted one. The one I saw was a Dorian and was $180 so I set out to make my own. I hope you will take the time to comment, share your knowledge on how it can be made better, better tooling choice, better method or what have you.
The first step was to select the steel for the project. I found a piece of salvage that said "A2 tool steel" that was close enough. It ran 32.5 cents per pound so the 2"x 2.5"x3.25" piece ran about $3.50.
I mounted it in the 4 jaw centered between the 2" width and .875" in from the side opposite where the dovetail would go. Here it is faced just to smooth it up.
Next was to drill it 3" deep starting with a center drill and working up to 7/8" which is my largest bit. I left the hole blind bottomed so that coolant wouldn't run through the head stock onto the ground, plus the chuck wouldn't be throwing it.
Next was to bore the hole. My boring bar was a little small for the task so it was .010 at a time with frequent spring passes. The Shar's high-precision 5C collet set measured 1.248" so I bored it to 1.249". Worried that heat could cause it to stick I honed it later to clean it up and have just shy of 1.250" bore. (Note to self: Figure out how to fit "a larger boring bar would make a great stocking stuffer" into dinner conversation.)
The test fit looks good.
Next step was the taper. I found where the collet is 10 degrees but the holder taper should be 9 degrees 51 minutes so the clamp pressure is on the end. So with the cross slide set I cut the taper.
The first step was to select the steel for the project. I found a piece of salvage that said "A2 tool steel" that was close enough. It ran 32.5 cents per pound so the 2"x 2.5"x3.25" piece ran about $3.50.
I mounted it in the 4 jaw centered between the 2" width and .875" in from the side opposite where the dovetail would go. Here it is faced just to smooth it up.
Next was to drill it 3" deep starting with a center drill and working up to 7/8" which is my largest bit. I left the hole blind bottomed so that coolant wouldn't run through the head stock onto the ground, plus the chuck wouldn't be throwing it.
Next was to bore the hole. My boring bar was a little small for the task so it was .010 at a time with frequent spring passes. The Shar's high-precision 5C collet set measured 1.248" so I bored it to 1.249". Worried that heat could cause it to stick I honed it later to clean it up and have just shy of 1.250" bore. (Note to self: Figure out how to fit "a larger boring bar would make a great stocking stuffer" into dinner conversation.)
The test fit looks good.
Next step was the taper. I found where the collet is 10 degrees but the holder taper should be 9 degrees 51 minutes so the clamp pressure is on the end. So with the cross slide set I cut the taper.
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