Machining a Drawbar

Not sure how you would use axially. how would that negate the twisting forces of tightening and loosening?
Thinking again about using a single piece. It would be good practice using a follower rest plus it would insure you bar is straight.
 
ddickey said:
Not sure how you would use axially. how would that negate the twisting forces of tightening and loosening?
Thinking again about using a single piece. It would be good practice using a follower rest plus it would insure you bar is straight.
Click to expand...
When doing the pin axially, you just drill the hole in between the threads, from the end, it acts as a key would in a shaft would.
 
This wont be helpful to ddickey but I thought it was interesting to read the post about making a drawbar today, since I just broke mine 2 nights ago and built one this morning.

This is pretty identical to the original, only longer by about 1.25 inches. Anyway, noone in the town I live in had any 3/4 steel hex shaft, or 7/16 steel rod so this is all made from stainless. I had to use 7/16 due to clearances and this was all I could find.

The old drawbar was NOT threaded on the top, just pinned(approx 1/8 pin) I've broke the pin 2 times now, which is why I built a new one. I threaded mine on both ends. Didnt use the lathe(dont know how to thread yet) except for putting the die in the chuck and indicate it, then put the rod on the tailstock and manually turned the chuck to start it. Quit giggling I know there are better ways!:-) The first set of threads I did by hand werent exactly straight and I cut them off. These threads now are really straight and the drawbar works fine. Since I made mine a little longer i made the bushing on the left to compensate. Being longer I can possibly repair in the future if need be.

Main question Do you guys see any issues with using the stainless?


drawbar.jpg

drawbar 2.jpg
 
We always made the replacement bar from 7/16" ETD150, then threaded and pinned it into the old nut.

This is the tool you use loosen the drawbar and avoid mushrooming the nut:
WP_20181109_14_40_20_Pro[1].jpg
Made from an old VW lug wrench.
 
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Hi Guys,

My mill uses an MT3 taper ! I never tighten the drawbar more than hand tight, and I certainly don't have to bash the hell out of the drawbar to get it to release. If you are having to give the drawbar a good bashing then you are over tightening it.
 
These are the drawbars & drawtube that came with mine. Only the drawtube will draw up properly. I could make bushings to make the others work.


20170427_173515742.jpg
 
Dhector said:
Main question Do you guys see any issues with using the stainless?
Click to expand...
There are lots of varieties of stainless, and they vary considerably from one to another. The biggest issue with stainless with a drawbar, with some stainless, might be galling the threads in the collet. A little Never-seez on the threads may help stop galling. Not a bad idea on any drawbar.
 
Bob Korves said:
There are lots of varieties of stainless, and they vary considerably from one to another. The biggest issue with stainless with a drawbar, with some stainless, might be galling the threads in the collet. A little Never-seez on the threads may help stop galling. Not a bad idea on any drawbar.
Click to expand...

Thank you. Its all I could find in town. Obviously I'm new to this and was worried. It seems to work really well so far, but havent used it much. It does thread in very nice I must say, unlike the first set of threads I did by hand. Even without the hex on the top in threaded in tight. I knew that wasnt going to work. Thanks again.
 
Just ordered some split pins and 24" x 1/2" 4140HT from Mcmaster Carr. $9. Didn't think that was to bad.
 
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