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Back gear kicking out

torker

Cast Iron
Joined
Dec 3, 2003
Location
British Columbia
I have to drill a bunch of 3/4" holes-1 3/4" through 1 1/4" plugs, CRS. With all the heavy work I decided to grease the backgear spindle before I went any further. I drilled two holes and all was fine. Went out to the shop this morning and now the back gear keeps popping out. I see some set screws under the shaft at the rear. Do these need to be adjusted now or did I pump in too much grease or....what the heck did I do here. Thanks.
Russ
 
I should have said...this is a SB9C. I've got a hundred of these holes to drill, Is this too much for this little lathe or should I be doing this on a drill press? I've tried it both ways...the press is faster but the holes aren't as accurate. Lots of cranking on the hand wheel!
 
There are two adjustments for the back gear. The rear most set screw adjusts how far in the gears will go so you can get proper back lash. The forward most set screw adjusts tension. This is probably what needs adjusting in your case. The set screw should have a spring and a piece of brass under it. The brass rides against the back gear eccentric. Be sure to check that the spring and brass are indeed there or adjustment may be impossible. You should tighten the set screw up so that a bit of effort is required to engage the handle. It won't jump out of gear once you get it right.

Regards,
Dave
Meridian Machinery
http://www.mermac.com


[This message has been edited by Meridian (edited 02-24-2004).]
 
torker,
Provided you get the back gear working again, it would be easier, and maybe quicker over all, if you made a simple block to mount in your toolpost so you could attach a drill chuck to it and could feed with your carriage instead of cranking the tailstock.

I mounted the block in the toolpost and put the tools in the lathe chuck to drill and ream the hole in the block. Finish it off with a set screw or two. Guranteed to be at the correct height for your lathe and not difficult to dial in for future jobs. This adds the ability to power feed and it takes a lot of wrist strain out of repetetive drilling.
 
Thanks guys....Dave,do you mean the two small threaded holes right on the top? There are four actually..two app 1/16" (oil holes???) and two threaded holes. I thought the threaded holes where just oil holes till I just found out they are threaded. Should there be a small piece of brass and short springs in these holes? I ran one of the cover screws into the hole and it does lock the back gear so I assume this would be correct.
Vinito...I gotta check this out. Power feed would be great. I may end up doing a few hundred more of these things and wasn't looking forward to it.
Even... I just had the headstock out and lubed and adjusted according to all the info I could find. My old motor is pretty small but seems to take the work load better than the newer offshore stuff.
 
Ooops...that was dumb! The two holes ARE for the covers.(in a big rush to get these holes drilled...starting to be ruled by panic) I don't see any other screws other than the two set screws at the back, on the bottom. Are one of these for adjusting the backlash and the other for adjusting the tension? One has a jam nut...the other (towards the tailstock) is just a square head bolt. Thanks again.
Russ
 








 
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