Chester (Luxcut) Champion 20v Mill x & Y backlash

Hi

I have just got a 2nd hand Luxcut DM20vs mill which is essentially a Champion 20V (see my album). It is about 9-10 years old and has a bit of backlash in the X & Y leadscrews.

Can anyone please advise on how these can be adjusted?

Does anyone have a decent manual for this as the Chester and the Luxcut user manuals are rubbish.

Regards

Bruce

Bruce,

pm sent.......

For reference, my backlash was about 0.1mm on the X slightly less Y, it doesn't sound like much and I think that is half the factory spec, but if my quick maths is right on a 2mm pitch screw, that translates to 18 degrees of movement in the hand wheel, which is pretty significant.

I consider 0.1 to be quite loose, I could have got it much lower without causing too greater increase in friction but I don't want to wear the screw out in the middle.

Wiess/Optimum have a slightly better manual available by searching online, but I think its much the same thing just clearer.

Edited By Russ B on 03/05/2015 12:25:58

Grizzly Tools have the best manuals. They may not be identical machines to those found here but are often similar enough to be useful. This looks like yours but may be one of the others on the Grizzly site, have a look.

http://cdn2.grizzly.com/manuals/g0759_m.pdf

The backlash can be adjusted a bit by tightening grub-screws in the split bronze female thread bosses - which are inside the base. Not a wonderful engineering solution, but ...

Access is by removing the table. I have done this but I do not recall the exact details - it seemed to be fairly straightforward once you realise how to get the gib strips out. ie: endways from one end only when the large headed adjuster screws are removed. The strips are tapered lengthways so if you tap lightly and the table tightens up, that is the wrong end. You also need to remove one end handle of the X screw, I think the left one, and wind the table off.

I have a rather better manual from Optimus in Germany, - the Chester one is a photo-copy of some of this (ie with bits missing) but I have been told since that the Chester mill is not made by the same firm as Optimus's version.

If I can help further please ask

Regards, Tim

If you download the Grizzly manual, see items 66 and 71 on page 4. They fit in slots in the part 68 - and if the screws that clamp 66 & 71 in place are not tight, you will get extra backlash even with the grub screws gripping the thread well. And of course, any wear on the thread will mean more backlash in the middle than at the ends of travel (or OK in the middle and tight at the ends).

A DRO helps to minimise the problems of backlash, in many respects.

Cheers, Tim

Thanks for all your responses. I will keep you all informed of my progress

Vic - you are the man

I knew I should have looked at Grizzy but I didn't get around to it.

The Y Axis looks like it will be fun

Thanks again

Bruce

Personally I wouldn't worry about it. My mill has about 0.8mm of backlash on the Y-axis handle and 0.7mm on the X-axis handle. It's been a while since I adjusted the anti-backlash nuts, but all that generally happens is that the whole thing jams up at the ends of the travels if too much backlash is taken out in the middle. The backlash doesn't seem to affect my 'ability' to make parts that fit. To be fair though I do have a DRO.

Andrew

I think nowadays people expect far too much from relatively cheap hobby machines,in times when manual machines were the norm ,nobody worried about backlash you just got used to it and got on with the job and allways worked in one direction,it was more important to have free running slides and handles and it was more important that the results were repeatable . That is wind the table to an index point on the dial ie say zero,take cut on a component , put another component in the fixture wind forward to the same index take a cut and get the same result. A nut which is too tight will wear out quickly . Some mills had backlash eliminators in various forms for climb miling ,but usually worked on the principle of two nuts on one screw working against each other,with an operating lever which operated the mechanism to tighten the second nut ,when climb milling was not required the second nut was slackened off with the lever to prevent extra wear on the screw and nuts.