Slideway reconditioning?

[Archie]

Last year I bought a cold saw similar to the one below. Sorry, it's the best photo I could muster.

It works a treat with one rather critical exception: it cuts on the ****!

Currently I'm not massively bothered as it's only out by a small amount but I've got a job coming up that is likely to require a bit more accuracy so thought I'd see if anything can be done to sober it up! I think I've diagnosed the problem as a worn slideway. The pneumatics push and pull slightly off centre of the slide which causes a moment and has, over time, worn it down. So to my question: assuming my diagnosis to be correct what, if anything, can be done?

Guess I've learnt a lesson about not buying unseen!

 

[brightspark]

doesnt it have a tapered gib strip that can be tightened up on the slide or. gibstrip with small grubscrews with nuts on to take up slack ?

 

[Archie]

Good question. Not that I recall seeing but I'll be double checking!

 

[Wedg1e]

doesnt it have a tapered gib strip that can be tightened up on the slide or. gibstrip with small grubscrews with nuts on to take up slack ?

Even if it does there's a good chance that if they've been run unadjusted for some time, the slideway will be worn as the OP says... in which case tightening them up now will make the slide run slack - tight - slack... or tight - TOO tight - tight, depending on where the sllide is when the gibs are altered.
A common dodge used by unscrupulous lathe/mill sellers is to slacken all the gibs off so that it's as sloppy as hell to disguise the worn ways, then tell the buyer "oh, they need adjusting, I forgot to do it..."

 

[brightspark]

Even if it does there's a good chance that if they've been run unadjusted for some time, the slideway will be worn as the OP says... in which case tightening them up now will make the slide run slack - tight - slack... or tight - TOO tight - tight, depending on where the sllide is when the gibs are altered.
A common dodge used by unscrupulous lathe/mill sellers is to slacken all the gibs off so that it's as sloppy as hell to disguise the worn ways, then tell the buyer "oh, they need adjusting, I forgot to do it..."

true the proper way would be get them re machined or if u have a lot of time rescrape them in . tightening them up slightly will take up part of the wear but not all .as u say it will be tight and slack the only other thing i can think of failing all else if its only the last few inches that are worn on slide and theres enough height in saw to loose an inch or so/ pack the vice up a few inches if its posible that will clear the worn part unless it interferes with stops ect

 

[MrFluffy]

The proper way would be to strip it, get the slideway ground plane and pack up the saddle which runs on it by the amount removed.
It may/may not fit on a surface grinder or be vee and flat or something all of which will complicate it and if so your into finding someone who can regrind vee and flat surfaces etc which will be expensive.

Dont waste your time trying to grind it in situ, as the wheels set up will simply follow the wear and make a cats bottom of it.

The unproper way, if its consistant, shim it somehow so it cuts vertical

 

[Mad Mick]

If you cannot fix it,suggest you clamp workpiece to rear jaw(static half) of vice with carver clamp or similar,(been there done it!).Regards,Mick.

 

[Archie]

The unproper way, if its consistant, shim it somehow so it cuts vertical

Glad to hear I'm not the only bodge artist round here! I'm pretty sure the list is always to the same degree so that may well have to be the solution. I really just wanted to know if there is a 'proper' way of doing it. Regrinding sounds pricey.

 

[miller]

Have a look on homeworkshop.org.uk there is a chap on there that regrinds beds and seems to have a good name for quality and price ( thats only what i have picked up from postings) .

 

[Archie]

Thanks Miller. That's handy info. However, I'm being a bit dumb because I can only find adverts on the site and no mention of slideways if I search. Is there a forum-type section I'm missing?

 

[Wedg1e]

One of the guys on the Boxford lathe user group on Yahoo reground his own V-&-flat bed... think he used the tailstock guide V (which was the least worn part of the bed) to guide a Dremel-style tool with a grinding stone along the worn faces. Reckoned it was messy but it worked!

 

[Archie]

Right. Small update. Finally got round to having a look and, result, there is a tapered gib strip to tighten up. Downside is it appears to have no effect as the taper is widest at the top and the slack I wish to take up is at the bottom. I'm wondering whether the strip itself (which is only plastic) is worn but I'm somewhat loathe to buy a new one as a) I can't guarantee it will fix the problem and b) Pedrazzoli's seller over here want £75 plus VAT and carriage for said piece of plastic! Think I'll try wedging it up with something else first and see if that really is the problem. In the meanwhile, does anyone know where I might be able to get the (possibly) required spare without having my trousers stolen at the same time?

 

[brightspark]

Right. Small update. Finally got round to having a look and, result, there is a tapered gib strip to tighten up. Downside is it appears to have no effect as the taper is widest at the top and the slack I wish to take up is at the bottom. I'm wondering whether the strip itself (which is only plastic) is worn but I'm somewhat loathe to buy a new one as a) I can't guarantee it will fix the problem and b) Pedrazzoli's seller over here want £75 plus VAT and carriage for said piece of plastic! Think I'll try wedging it up with something else first and see if that really is the problem. In the meanwhile, does anyone know where I might be able to get the (possibly) required spare without having my trousers stolen at the same time?

might be grasping at straws but can u get any thin shim behind the gib strip where u think its worn

 

[Keith 66]

I recently got a quote for reginding a lathe bed from the Company on Home workshop, reasonable price too, blokes name is Brian Caddy & website link is,http://www.slidewayservices.co.uk/index.html

 

[Archie]

might be grasping at straws but can u get any thin shim behind the gib strip where u think its worn

Dunno but I think something along those lines is my next plan of attack!

I recently got a quote for reginding a lathe bed from the Company on Home workshop, reasonable price too, blokes name is Brian Caddy & website link is,http://www.slidewayservices.co.uk/index.html

Cheers Keith, that's handy to know. If I can't bodge it I'll try them.

 

[Pete.]

You could always drill & tap the slide for flat-gib adjusters and use them to adjust the tapered gib.

 

[Archie]

Good plan, that man! I'd rather not but if it comes to it....

 

[Archie]

One saw suitably bodged! Made a small wedge from a bit of copper bar and stuffed it between the über expensive plastic bit and the metal. Works a treat.