Thread: Hembrug lathe on the way.

Originally Posted by caskwarrior

A tap is obviously an option, but i would be worried about a loose fit on the slightly worn screw. Only $100 from McMaster Carr so thats low enough to experiment i guess.

Having done the boring bar thing for small internal square and ACME threads, I'll offer some advice.

Buy the tap(s).

Getting a chatter-free finish isn't easy. Last time I did this I made the taps from silver steel. That was 20+ years ago and the internet flea market didn't exist.

PDW

I have some thread wires mate. I won't vouch for their quality but you're welcome to them if you need them.

For some reason the cross slide screw on my 10EE measured 0.6" OD, it is 8tpi left hand ACME. I made a new cross slide screw and a tap at the same time (out of 4140 steel).

As 0.6" is 0.025" under 5/8, you are welcome to use my tap as a rougher to make a new nut. I could post it to you. It would take a lot of strain off any tap you buy. My tap is no where near as good as any commercially made tap, but should suffice for roughing.

tap1.jpg tap2.jpg

Originally Posted by .RC.

For some reason the cross slide screw on my 10EE measured 0.6" OD, it is 8tpi left hand ACME. I made a new cross slide screw and a tap at the same time (out of 4140 steel).

As 0.6" is 0.025" under 5/8, you are welcome to use my tap as a rougher to make a new nut. I could post it to you. It would take a lot of strain off any tap you buy. My tap is no where near as good as any commercially made tap, but should suffice for roughing.

tap1.jpg tap2.jpg

Impressive RC!

Had to quickly make a special puller/pusher in order to remove the rear bearing cage and tumbler reverse drive gear, thanks to Hembrug for providing rough drawings of all the servicing tools in the manual. I am still a bit stumped as to how to actually remove the tumbler reverse mechanism itself.

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Ralph,
What I recall is I removed the spring knob on top of the handle (single screw on top) and reached in from underneath to reach the tumbler housing. I think the housing is screwed to the axle that attaches the gears in the gearbox. Once the housing is unscrewed it can be taken out. I remember it being a lot easier than I imagined it would be. The key was opening the door to the motor and reaching in from there.
Hope this helps,
Peter.

I had stalled on this a bit while I got my dividing head back into working shape and changed jobs, only to get cracking on the gears and find out all the gears are mod 1.5 EXCEPT the tumble reverse which are mod 2, so now I have to wait for more cutters to arrive. Bummer20171020_222716.jpg
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Also that hardened inner sleeve needs to be pressed into the new gears does the normal .001 per 1" of diameter rule apply in plastics or should I be looking to do a loctite fit, these need to run really true as theoretically the feed drives may be used at very high rpm.

I have some Mod 2 cutters here if you need them...

Michael

Originally Posted by caskwarrior

I had stalled on this a bit while I got my dividing head back into working shape and changed jobs, only to get cracking on the gears and find out all the gears are mod 1.5 EXCEPT the tumble reverse which are mod 2, so now I have to wait for more cutters to arrive. Bummer20171020_222716.jpg
20171020_222803.jpg

Also that hardened inner sleeve needs to be pressed into the new gears does the normal .001 per 1" of diameter rule apply in plastics or should I be looking to do a loctite fit, these need to run really true as theoretically the feed drives may be used at very high rpm.

Ralph,
I have not made these gears myself, but have a friend who manufactures gears professionally and who has made the fiber wheels for different sellers. All I can tell you is he makes them for press fit. Usually he makes the gears and the user changes the bushing and needle bearings himself.
Peter

Thanks very much for the offer Michael, but i figured I would just get the set, mod 2 seems a handy size for project gears in the future. To top it all off today i was facing a big disk on my other lathe and ran out of cross slide travel, the feed overload clutch kicked in, but not before the apron feed select rod twisted, this was broken before I got the machine and i have made it once before. Not a fun job to get to it though 20171023_185612.jpg

Well I got the big lathe running again and finally made the broken tumbler reverse gears, there were little hardened bushing inside the old phenolic ones that had to be pushed out and pressed into the new blanks but it runs nice and quietly. They were mod 2, 22 teeth.20171201_101513.jpg20171201_101320.jpg20171127_112405.jpg20171126_161912.jpg20171126_161900.jpg20171126_160401.jpg20171126_124014.jpg