Tightening up the backlash in my Kearney & Trecker
Tightening up the backlash in my Kearney & Trecker
Is it possible to tighten up the backlash in the y-axis of my Kearney & Trecker 2H Universal Mill? It is a 1950's model. I suppose I should also ask the same question of the x axis?
Re: Tightening up the backlash in my Kearney & Trecker
There are probably a few owners of the great K&T around here. I think the usual reduction of gap at the end of either lead screw is too simple. This machine has, no doubt, a more sophisticated means of altering the contact of the nut. Whereas it would seem that the table must be removed, I believe there is a work-around way of coming into the knee or other access to this adjustment.
I don't have the answer, shouldn't have replied, yet the answer may...I couldn't resist displaying my interest.
I don't have the answer, shouldn't have replied, yet the answer may...I couldn't resist displaying my interest.
Re: Tightening up the backlash in my Kearney & Trecker
I've never seen a K&T, but every machine I've worked on had several sources of backlash. The screw mounts, thrust bearings, the handles, the nut mount, and of course any wear in the screw and nut. You need to assess what moves while the backlash is being taken up, and fix those. Once that's all done, you're left with the wear in the screw / nut.
That wear can also be roughly assessed if you can see the nut easily. See how much the screw moves in and out of the nut while you turn the screw back and forth. With no wear, the screw threads don't move in relation to the nut, they just screw in or out. With wear, the threads visibly move towards or away from the nut when you turn the screw. I expect your K&T has some mechanism for taking up wear on the screw - double nuts that get moved slightly apart is a common way. Set them so the screw is slightly tight on the extreme ends of the movement, but you're stuck with whatever backlash you have in the more worn part.
That wear can also be roughly assessed if you can see the nut easily. See how much the screw moves in and out of the nut while you turn the screw back and forth. With no wear, the screw threads don't move in relation to the nut, they just screw in or out. With wear, the threads visibly move towards or away from the nut when you turn the screw. I expect your K&T has some mechanism for taking up wear on the screw - double nuts that get moved slightly apart is a common way. Set them so the screw is slightly tight on the extreme ends of the movement, but you're stuck with whatever backlash you have in the more worn part.
Re: Tightening up the backlash in my Kearney & Trecker
Good morning I would be glad to take some photos of my 3ch which is disassembled so you can see the potential areas of backlash problems/adjustment. I know that on the X axis there are two leadscrew nuts that can be adjusted, twisted for adjustment, I think, on the y there is no adjustment on the nut/screw. There are a whole bunch of gears involved between the cranks and handles. I don't know of a way to adjust the play out of the gears. But having said that, if there is play in the roller bearings the shafts sit in the gears will have excessive back lash.
A friend of mine suggested cutting a grove in the nut for the lead screw and putting an O-ring in the grove to take up the backlash. This seem like a temporary repair. I think your machine lay out is the same as mine. And the y axis lead screw nut would be relatively easy to replace. We are talking about a Kearney Trecker and "relatively" is a relative term.
Email me at rockettelectric@gmail.com If you want some photos or continuing advise. Keeping in mind, of course, advise is free and the value therefor suspect.
Tim
A friend of mine suggested cutting a grove in the nut for the lead screw and putting an O-ring in the grove to take up the backlash. This seem like a temporary repair. I think your machine lay out is the same as mine. And the y axis lead screw nut would be relatively easy to replace. We are talking about a Kearney Trecker and "relatively" is a relative term.
Email me at rockettelectric@gmail.com If you want some photos or continuing advise. Keeping in mind, of course, advise is free and the value therefor suspect.
Tim