Take the "float" out of the cross slide??

[BK]

I've bought this Chinese lathe new 4-5yrs ago and have learnt to live with this problem, (you get what you pay for) the marketers , Hafco, call it an AL 320G, the mannual (that's how it's spelt on the cover) calls it a L141.
My idea is to fit a second nut to the cross screw (as it only has one,  )  so I can take the play out, has anyone done this?? What's involved?? is there room??
Help please. 

[BK]

That's exactly what I need, thanks for the link. 
Now to take the plunge and pull 'er down, soon.

[Davo J]

The nut on the 12 x 36 lathes have a saw cut across them leaving about 5mm at the top and it is about a quarter of the way in from the back. It has 2 jacking screws in the bottom to adjust backlash. This would be easy and simple to add.
This is a quick picture

Dave

[No1_sonuk]

I think the nut on my Chester DB7 has the slot opening at the top and a "spreader" screw, similar to the idea used in split dies.

[Davo J]

Some of the Grizzly machines are also at the top as well. I think they put my split from the bottom up is because there is more thickness at the top. The bottom of the nut to the internal lead screw thread is only about 7mm on mine.
My grub screws for backlash adjustment on mine also spread the 2 parts of the nut. They thread into the thin part and push against the larger part, spreading them apart.

Dave

[BK]

Fixed  Mine also has a slot, on the top, I nipped that up a couple of times and tried it, third time lucky, no more endplay. 
Thanks for the input, now, I wonder if the compound is the same, it's off so I'll check it too.

[Davo J]

I think you will find the compound one is just a round bronze post with a thread in it. A friend of mine bought a Taiwanese lathe from Hare and Forbes and it come with a load of back lash in the compound. He said he squashed the nut in the vise and that fixed it. I am not sure which way and haven't had to adjust mine yet.

Dave

[BK]

You are spot on Dave, it's just a brass block affair in the compound no adjustment, it dosn't need adjusting but while it was off was a good time to check.
Here's the one on the cross slide.



I might try parting steel now, it always grabbed and broke blades, OK on brass.
Thanks again.

[Andrew_D]

So what did the old-timers know that we don't??? The reason I ask is my old McDougall just uses a bronze/brass/??? block with a threaded hole in it. This is a WWII-era 20" lathe. The block for both the cross-slide and compound is about 1.5"-2" long, the shaft is about 5/8" diameter, 0.200" per turn. (rant on - There are times I'd like to punch the guy that decided on 5 tpi...hard to turn the compound smoothly and get a nice finish - rant off.) The compound has 0.005"-0.006" of backlash, cross-slide has about the same. Obviously it has worked for these older lathes....

Different grade of material to make the nut?
Threaded hole slightly undersize?

Obviously they knew something back then.....

Andrew

[lordedmond]

Better brass in them days

Ive got some at the moment pedigree unsure ,but it turns like EN1A the chips come off in spirals and hot they change colour to dark straw , HSS turns its nose up so I have resorted to carbide ( for brass  )



but the finish is very good


Stuart