Bantam cross slide screw.

Hi chaps I have a problem? I can hold the crossslide and move it backwards and forwards by hand, I would say in the 40thou department, I've had a look and there is a bit of play in the nut on the lead screw so I may have to make another one but does anyone know what the hole in the cross slide is for in the picture, it has a very small hole in the bottom for maybe a ball bearing but not sure, whatever should be in it is long gone, the hole is threaded by the way.

Thanks Alan.

I forgot to load the photo I'll add it in a mo.

Hi Alan,

Most lathes have some movement in the nuts of lead screw and cross-slide screws but this does not cause a problem because the nut is only loaded in one direction. 40thou in an old lathe is not uncommon. It is good practice to always back off the cross slide prior to moving it into the forward position for machining the part.

Paul.

Although not a problem for general turning this play can make operations like parting off difficult.

Earlier this year I made a new cross slide for my lathe and at the same time replaced the feed screw and nut. My machine is metric and I bought a length or leadscrew from "Automotion Components" plus a nut that I could adapt to suit my lathe. The items are not expensive and a 1 metre length of screw was more than enough to make 3 feed screws. Backlash and parting off problems are a thing of the past and a couple of spares on the shelf !

Hi Alan

My Bantam cross slide doesn't have the hole you are pointing to, nor does it have many of the others pictured, just those at the side for fitting the cross slide stops when using the rotary capstan limit function.

Perhaps a previous owner has used it as a boring table and the screw holes were for holding a casting for boring/machining. Alternatively perhaps a tooling sub plate has been used to make the lathe more versatile.

Emgee

Thanks chaps I will have to make new ones I think, Chris the back lash when doing just normal turning isn't a problem but parting of is a different animal altogether you just can't do it unless it's ally or something soft, I've just finished scraping in a prisam to rescrape the top slide as it rocks slightly when that's done I'll tackle the cross slide.

Thanks again Alan.

I'll have a look at Debs lathe in the morning and see if that has the hole, from memory it looks to have quite a few.

I'll also check to see if I have a tap that matches the screw. Is yours an imperial machine ?

Thanks John nice to talk again.

Regards Alan.

Alan - have you got all the manuals, parts lists etc? I think must have the full set now if you are interested.

Murray

Thanks Muzzer but fortunately I have a book on the bantam thanks for the offer though it's very kind of you.

Alan.

Alan, you mentioning scraping the prism jogged my memory. Do you still need a sine bar ? I forgot all about it as I have been swamped with motorcycle work. Chris.

I made one for another job but dought it will be useful for this project, I may be interested Chris could you send me a personal message and maybe we can have a chat.

Alan.

Alan, no hole in my Bantam either, but maybe you could pop another oiler in it as it is over the lead screw, this will keep dirt out and oil on the screw. Could this hole have let c***p in the hole which wore out the lead screw nut?

Chris Gunn

No hole on Debs lathe either.

Feedscrew is 9/16" x 0.200" pitch twin start LH.

Had a look for a tap but don't have one that size, closest I have is M13 x 2.5 two start LH which is no good.

Don't know if it helps, but here's a picture of the cross slide on my Bantam (Mk2) which has various holes in it but not the one you've picked out.

Indication might be that the hole in question is an aftermarket feature?

HTH Simon

Edited By Simon Williams 3 on 11/11/2016 22:19:20

..Thanks for the replays chaps this has been bending me head so to speak, I was at the girlfriends last night and when Watching the telly it suddenly dawned on me the there wasn't enough backlash in the dial to cause me such a problem, so I got back this morning changed and went in to shed of dreams as my son called it lit the heater and then had a look at the bantam, there is only 10 thou of back lash on the dial but you could grab the crossslid itself and move it back and fort at least 60 thou, I remember a long time ago that I looked at the nut that holds the dial on and though what's the small nut in the middle for ? Now I know, what a bast--d there I was thinking how much of a PITA it's going to be making a new nut for the lead screw and all it took was a five sixteenth spanner and away you go, parts of a treat again the only thing I can think of at some point it must have come loose, I ground a new parting blade to size to fit in the tool holder honed the end up and away I went it even parts of using the power feed now what a result, anyway thanks again for all the advice and kind offers of help, just need to scrape in the top slide now and then good to go .

Regards Alan.