Maximat question

[PeteH]

Probably applicable to any lathe --

Is there an easy way to clean out the half-nuts (i.e. one that doesn't require disassembling the carriage) ?

Soak 'em with penetrating oil and blow 'em out with air ?

Mine have a fair amount of congealed grease (and probably some swarf) in them.

Thanks...

[oldvan]

I'm pretty sure that keeping the half nuts and leadscrew clean and lubricated will significantly extend their useful life.

WD-40, a brass wire brush, QTips, an old tooth brush, and some way oil sounds like a plan to me.

[Harold_V]

Not long after I purchased my Graziano, I had an issue with chips in the half nuts. Nothing I tried worked, as one chip had been firmly wedged in one of the nuts, which I discovered only after a partial teardown. The machine was not capable of generating a thread, as it would not track properly. In my case, I removed enough of the support system at the tailstock end that I could move the carriage off the bed far enough to expose the half nuts. I think that's what I did, any. This was all of 40 years ago.

This experience taught me a valuable lesson. As my power feed is not a part of the lead screw, it remains out of motion unless I'm threading. Before I put the lead screw to work, it is engaged, and the spindle started. I then blow off the entire length of the (revolving) screw, using air, then I oil the screw. Only then will I consider engaging the half nuts. This appears to have worked well, as I've never had another issue with chips in the half nuts.

Depending on how the machine is assembled, it may be possible to make a very short bend on a piece of TIG or gas welding rod so you can reach in and swipe the teeth, side to side, in the hopes that you can free the crud. If you start by applying a good solvent and allowing a generous soak period, you may be pleasantly surprised.

Or not!

Good luck, Pete.

Harold

[PeteH]

Good idea ! Thanks, Harold.

The outboard end of the leadscrew rides in a block that's bolted to the lathe base. Remove those two screws, pull the tailstock, and I should be able to run the carriage far enough down to get the halfnuts past the threaded part of the leadscrew, and access for brushing/scraping will be a piece of cake.

But being lazy, I'll try the solvent approach first.

As to cleaning the leadscrew before each use, AMEN ! (I wish the guy[s] who ran this thing before I got it had done so.)

[Torch]

Option B is a lead screw protector:

http://www.spiroflex.com/pdfs/Ld_scr_grds_A_B_eng.pdf

[Harold_V]

Option B is a lead screw protector:

lead_screw_protector.jpg

http://www.spiroflex.com/pdfs/Ld_scr_grds_A_B_eng.pdf

That's a excellent idea. Keeps not only chips from the screw, but abrasives as well.

Harold

[Torch]

That's a excellent idea.

Even a blind squirrel occasionally finds a nut.

[PeteH]

Amen to that. I do believe I'll be ordering one of those.

This demonstrates the value of this forum -- the way that people help one another.

Thanks, Torch !!!

[Torch]

You're welcome.

For the record, I have found them to be very effective. Every once in a while I pull them back (after cleaning off all the chips from the outside, of course!) and squirt a bit of oil on the lead screw. It's always nice and clean and oily inside. Just make sure you keep the retaining clips in a safe place after installing them as they are springs and do exert more force than is readily handled with one hand during the oiling process. You will also need to turn a cap for each end of each protector, to mate the ends with your carriage, gear box and end bearing.

BTW: on my machine, after the end bearing housing is unbolted from the bed, there is a roll pin at the gearbox end. Tapping it out releases the entire lead screw. Perhaps yours is similar.

[PeteH]

BTW: on my machine, after the end bearing housing is unbolted from the bed, there is a roll pin at the gearbox end. Tapping it out releases the entire lead screw. Perhaps yours is similar.

Yes, same setup, according to the breakdown diagram. (The machine's Boeshielded and wrapped in plastic right now, until I get some time.) But I don't think I need to remove the whole leadscrew in order to clean out the halfnuts. We'll see.. nothing's ever as simple as it seems at the outset.

Thanks again.