What's new
What's new

How to fix hand wheel wobble?

Tjugo7

Aluminum
Joined
Oct 12, 2011
Location
Stockholm, Sweden
Hello, I bought a new to me tiny but very nice mill. It is a Golmatic MD23 in nice condition except for a few issues.

There is a bit of wobble in the X and Y hand wheels. Is there a good way to fix this?
I could just put a pipe with a good fit around the shaft and bend it until straight. This however does not feel right since it puts a lot of force on the bearings and might also force the bearing out of alignment.

The X axis seems fine except the hand wheel wobble. For the Y axis it seems the bearing holder is out of alignment, since the axis bond about 20mm from the end (see picture). When I pulled the pins aligning it (the black part to right in the picture) and loosened the screws a bit the axis moves freely again, I hope new pins will fix this issue.

Y-slag-min.jpg

Regards Staffan
 
Sounds like your mill has been dropped.

First thing is to figure out where the problem is. Can you see the gap in the micrometer wheel changing as it goes around? If so, the end of the screw is likely bent. If not, the hole in the wheel may not be bored straight. If the screw is bent, take the screw out of the machine and straighten the bend. If the hole in the wheel is not straight, you'll have to decide whether to try to bush and re-bore the wheel, replace the wheel, or just live with it.

On the binding axis, the screw itself may be bent. Take it out, put it between centers on a lathe and indicate it to find out if and where it is bent. From there, it's just a matter of pressing the high spot back down with the screw between V blocks.
 
I have Hardinge (USA) lathes and have found that the slide rests, which are a separate accessory that is often removed from the lathe, are fragile. When dropped, the crank handle often gets bent. Even if the crank survives, the feed screw will be bent outboard of the support bearings. The screw is hardened, so the small diameter end that goes through the handle often snaps off.

So I have dealt with more of these issues than I wish, but I have learned to fix them.

The first step is to remove the feed screw and mount it by the bearing mount diameter in a collet in a good lathe (Hardinge). Next, I use a good test indicator to check for bending. I gently apply force with an adjustable open end wrench on the dial mounting diameter until it runs true.

If the screw is not broken or cracked, the job is done.

If the end of the screw is broken off, I silver braze a stub of steel rod to the screw and machine it to a duplicate of the original end.

Larry

DRB slide damage 1.JPG Hardinge slide rest 19Jan06.JPG DSC00122.96.jpg DSC00130cropped.jpg DSC00136small.jpg
 
Silver solder and brass rod are a great tool for broken machine parts. That's a nice repair L. Vanice
 
"Rigger Rash" is what I refer to bent leadscrews.

They stick out so nicely, to be a target.

N.C. machines are much nicer....just square boxes like worshing machines.
 
Had a very annoying guy looking at machines one day,already knocked over several things,started fiddling with a big old Cinci T&C grinder .I said"Are you buying it?" No ,he says ,because the handle on the cross feed wobbles.......I picked up a heavy 4x4 timber from the floor,raised it up,and bashed the handle in a temper...Nothing broke,and he tried the handle,wobble was gone.......then he quickly left.....he thought I was going to bash him.....and so did I.
 
I don't think it has been dropped, rather bumped or strapped down badly in the transport. If dropped there would be more visible damage.

Yes, I can see the gap in the micrometer wheel changing as it goes around. Considering the build quality of this thing I'm certain the bore in the wheel is straight.
So I'll take the screw out and try Larrys lathe collet prodedure. A good lathe for me will be Schaublin or Gildemeister and not Hardinge, quite sure it will work well anyway.

Regards Staffan
 








 
Back
Top