Anyone ever cut down a reamer shaft? I've got a 1" reamer that I need to be able to hold in a half inch chuck to ream polyethlylene. Tailstock is M2 and the reamer was not availiable in anything less than M3. By the time I added a M3 to M2 to a M3 reamer, it would be too long. Shaft is not real hard, file will cut the surface. Ideas?
Suggest use an abrasive cutoff wheel to shorten it, dont let it get very hot.....I have actually turned them before using carbide tooling.....your mileage may vary.
This should be done, or at least finished, on a cylindrical grinder IMO.
Grant
GMasterman wrote:
Just a question here.....why not bore instead of ream? I've done both in poly and have found that boring is worth the trouble. Reaming tends to be inaccurate due to polyethylene flexing under the cutting teeth. Also poly tends to make long stringy reaming chips which can pile up and be be re-cut/roll under the teeth which bunges up the quality of the hole in these sizes. I find that when reaming thick material at 1" dia I can get about 3/4 of an inch in while the chips exit the reamer well then I either have to back out because they start piling up or do some other monkeying to keep things going.
Oh yea...you have to take a pretty good bite with polyethylene or the reamer will expand the hole and skate instead of cut (or have things razor sharp)
Koz
Grant Erw> This should be done, or at least finished, on a cylindrical grinder IMO. >
Boreing has not produced the finish that I am looking for. Looks like the poly is soft enough tat it springs back after the boring bar passes, leaving a rough surface. I have made many smaller bushings, bored or drilled, then reamed to end up with a slick finish that I could not produce any other way. I drill with a 3/4" drill bit, then ream to 0.750 and it comes out perfict every time. Need to reproduce the same results in 1". BTW, a fortsner bit yealds a better surface that my indexable boring bar, but still not good enough to please me. Thanks!
Hmmm..interesting. Every thing I do is UHMW and at least 2" thick so it may change things a bit. I can get a fairly good finish reaming but the size is always out a few thou and any chips roller under the cutter the finish is shot. With the right feed and speed I can get what feels like a glass smooth finish boring that is dead on..using a not-too-sharp carbide indexable bit on the boring bar. The last boring pass needs to be greater than 1/16 so there is something to bite.
Fortunately, most of the tolerance I need to hold are +.005 and the finish can be "good enough". I'll try reaming with your method of taking nothing off but the fuzz just to see what happens.
Koz
GMasterman wrote:
turning the shank is no big deal if you use a carbide cutter. I'd recommend you add three flats for the chuck jaws. The 1/2" chuck will be a bit beyond its clamping capacity, the flats will drive live a beast.
your next concern is spinning the #2 adapter in its bore...
Yep, right now it's loctited in place. I did get a MT2 reamer today to clean up the tailshaft bore. Oh the problems of trying to get by with a 60+ year old Sheldon! Damn, now that I think about it, bet there's not many 60 year old power tools around still earning their keep but old mills and lathes. Guess that alone says something for US quality!
snipped-for-privacy@aol.com (GMasterman)
Can you "float" the reamer into the work? For example, if the reamer's tang end has a center hole (old ones would), use a dead center in the TS in it. Hold the reamer in place with a wrench that is long enough to bind on the lathe bed (wrench jaws gripping the reamer tang), and use the TS handwheel to push the reamer into the work (under power--a jolt at a time), same as you would do to tap a thread. Frank Morrison
Using that method I'd be afraid of missalighnment in starting. It won't take much to ruin a poly bushing if the reamed get out of line and bites in
I've done it, angle the compound with the reamer between centers, take light cuts, don't even need carbide for it. Just be careful that nothing happens to the center on the tang, if you ever want to sharpen the reamer and have it come out right. When you get close to size, bluing and a new or very little used sleeve will show you where the angle is wrong. Grinding would be the ideal way, but may not be available to you. Not sure I'd want to grind from a #3 to a #2, probably turn to within .010" or so then grind. The taper shanks aren't hard, but are still tool steel, keep the speeds down and you should be ok.
In the same line, I take broken TS drills and use the shanks to mount smaller drill chucks salvaged from burned up hand drills. cheap way to get around the 1/16 minimum on the half inch chucks I have. Just cut them off with a hacksaw, not an abrasive wheel. Reason should be obvious.
I cut an mt3 down to mt2 between centers, drive plate, slit brass sleeve to clamp to, using the topslide set to conform to an existing mt2 reamer taper, only any good if your reamer will accept a center at each end though. Not ideal I know but I only needed it for a short run and it did the job! Regards, Nick
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