CL300 carriage adjustment

The other day I noticed that the front of the carriage on my CL300 lathe had a bit of vertical movement. For those who don't know, the adjustment comprises a metal plate (front and back) which clamps under the lathe bed ways. Adjustment is via 3 clamping screws plus 2 jacking screws to set the amount of clearance. In my case the jacking screws were redundant as they had to be backed right out in order to clamp the other screws sufficiently to adjust out the vertical play. It is now OK but when it needs to be adjusted again, I think I have 3 options.

1 Remove the plates and machine them flat.

2 Clean up the other side of the plates and turn them over.

3 Make some new ones.

If I went for option 3, what would people advise I made them from. Mild steel, cast iron or some form of bronze?

I will start the ball rolling, and suggest 3a ... Gauge Plate

By the end of the day you will probably have votes in favour of every other option.

MichaelG.

I followed Dave Fenner's method from his books on the mini lathe for my CL300. I used EN3A and managed to buy some 3/4" x 1/2" section. I had to mill out some clearance over the saddle traverse gear. Then just drill the outer two clamping holes. Tip is to change socket cap screws for hex head screws. Its easier to make adjustments with a spanner than dropping the leadscrew to get an Allen key in. Now comes the patience bit. I made brass shims with a hole in small squares of shim just to go between where the bolts are and the saddle. Aluminium drinks can material is allegedly good for making shims. Not tried it myself. By trial and error got the saddle to feel as if it were floating on a film of oil without play. The rear one is most important to get right. Almost certainly you will have to remove paint and use cheapy diamond laps on the underside of the bed. I can assure you the effort was worth it.

After the CL300 sadly died on me I have just been through it all again with a Chester Conquest. Yes it is worth it. I am experimenting with a CZ121 brass front shear plate which is 3/4" x 1/4" section and will just go in above the traverse gear. The rear shear plate remains EN3A.

If you are worried about shimming or making shims. It is written that Myford use this technique and you can obtain a range of laminated shim thicknesses from their spares people.

Regards.

Edited By Ian B. on 16/11/2020 09:14:13

Sorry Anthony, I have just checked my old notes from the work on the CL300. I also had the problem of running out of adjustment with jacking screws. When I removed the saddle and did some deptchecking one corner (right hand front) was over depth. The face of the shear plate was clear of the bed no matter how much clamping force was applied. The saddle had been machined a little out of square shall we say. I set it up on its back ensuring the root of the Vee groove was parallel to the mill table along with the flat rear face. Then with trepidation milled off 10 thou across the shear plate mounting faces. It was surprising just how far out it was with the cutter removing only a couple of thou at the parts which could be clamped. So I ended up when returned to the machine with a gap such that measurements could be taken and a start point for the solid shears had opened up.

It sounds an awful lot but doing it is not so hard as writing itand remembering the detail. The other thing is those push-me pull-me plates as delivered seem to be made from poor quality cast material which is very prone to cracking.

Regards

That is a really good idea, obvious when you think about it. I did things the hard way and cut down the Allen keys to fit without removing the lead screw.

I did wonder whether anyone had come up with a design for taper gibs to replace the present arrangement. If not, I might have a look at that when my current project is finished.

+1 Gauge plate (Ground Flat Stock)..

..isn't the danger with brass that steel or iron particles get pressed into the softer surface and then start to wear the bed itself?

Yes Anthony, there are designs out there for taper gibs. Again one of the better ones is detailed in Dave Fenner's books in the Workshop Practice Series. These were taken from another exponent of the mini lathe. Frank Hoose. His website www.mini-lathe.com is a mine of information. You can also find references to the work of Vikki Ford along with links to further information.

Hope that helps.

Regards.

Hi Diogenes, For the brass question, I really don't know. I want to find out. Certainly it work hardens and is harder than the possibly poor cast material of the OEM originals as supplied. The other thing is that most of the suppliers now advertise these machines as having hardened bed ways. How good generally I could not comment. However with this latest machine the Conquest the underside of the ways was hard and could not be filed and it was needed. Hence all the work with cheap diamond laps of the plastic backed variety in the tight spots.

The machine had barely been used when I made the mod. Yet the original items had only been in contact at each end with telltale marks tapered by maximum 3/16" x 5/16"long tapering to nothing at 5/16" length and had been gouged away. It was almost nothing at the bad saddle corner but the corner of the bed had dug into it about 1/8" in.

Hi there Ian. I do have the Dave Fenner book, which I bought when I got the lathe about 12 years ago. I haven't looked at it for ages but it's probably where the thoughts about the taper gibs originated. I will dig it out and have a look. Thanks for the information.

regards

Anthony