I have a lathe but no mill. I'm looking at getting a tabletop 3 axis tramme l CNC, which I think will be cheaper and more useful for me than a knee mil l, but I have a project which would require a lot of collet slotting in del rin, and this machine seems not the best choice. I feel like I've seen a de dicated machine, but don't remember where. Also, I'm wondering if some sort of sharpening machine could be adapted. Thanks!
On further thought, maybe I could mount a small motor fitted with a slotting saw to my lathe carriage or compound, and mount an indexing wheel to the back of the spindle. This seems like it could be done cheaply if I could find the right parts.
ing saw to my lathe carriage or compound, and mount an indexing wheel to th e back of the spindle. This seems like it could be done cheaply if I could find the right parts.
Hi Robert,
Or an arbor in the lathe's chuck with the slotting saw, and an indexing fix ture mounted on the cross slide or compound. You did not say what type col let, so hard to help with the fixture, but no extra motor would be needed t hen. Hex stock makes for an easy indexing fixture if it fits your needs.
Delrin should be easy enough to slot, just don't melt it by going too fast. I imagine de-burring is going to be tricky, best to avoid burrs in the firs t place.
If I had to do it, I'd use the small Burke #4 horizontal mill that I've got .
G'luck.
Yes, that makes sense. From the photo you can see it's a very simple slotti ng operation. I wouldn't be doing the tapered thread you see there. I haven 't decided on four or six slits, so a hex or square rod would be enough for indexing. I still can't quite visualize the fixture involved, but perhaps it could be as simple as a bracket mounted to the compound which holds a sq uare or hex block center-bored and threaded to accept the threads on the co llet. That would be cheap enough!!! Thanks
Burke or Nichols hand feed mill? These have a lever with rack & pinion instead of a hand crank and lead screw for the longitudinal feed.
Thanks, but I'm looking for something much smaller, cheaper, and lighter!
There's also the Barker mill, which uses 3c collets for a max capacity of
1/2" and takes up very little space.
Agreed. I've got a Nichols horizontal mill, and that is what I would use (with an index head, or perhaps a makeshift one for just this task). But I'm not sure how easy that will be for robobass to get. I think that he's in Germany? There may be equivalent machines there, but probably not many by those two names. they are not exactly light for shipping. My Nichols was something like 1100 LBs (make that about 500 kg)
Note that some of the Nichols mills (in particular, the "toolroom" model) have the choice of a lever feed for the X axis, or a leadscrew with a half-nut which drops by removing a screw, and allowing it to hang from a stripper bolt while you put the other bolt back in place. And yes, I use it in both formats from time to time.
It comes with a three phase motor, and mine at least is 240 VAC, so I don't know whether that would be a problem as well. But it runs slow enough so overheating the Delrin would not be a problem.
You probably want support for the Delrin -- plan on an arbor inside it as well as the grip on the taper. And before you make the actual runs, run the saw to cut grooves in the arbor (and make sure that your index system will always use the same arbor positions.
If you were to do it on the lathe, I would suggest a modification of the usual milling attachment which replaces the compound. You want at least one axis with lever feed instead of leadscrew so you don't crank forever on the cuts.
Good Luck, DoN.
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