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Help with new lathe ways not straight... ughgh!

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Plastic
Joined
Aug 19, 2021
Hey Guys,
Recently bought a Taiwanese AL-960B- Was told it's a great lathe for the money. Purchased new.
I noticed it's cutting a taper but only right near the spindle, in the last 30mm or so, and it tapers about 0.1mm over that distance.
Along the bed up until then it holds dead on.
Lathe bed.jpg
On closer inspection and holding a straight edge up to the joint, I notice the ways are not straight, or aligned properly. It's not much, but I'm guessing enough to cause the taper in that area. Has anyone got experience with this? I can't explain why it wasn't just a single piece! Freaking annoying. I noticed the tiniest amount of "wobble" on the straight edge when placed along the edge closest to the spindle, on the flat way, and pushed closest to the apron, i got a small amount of deflection at the joint.
Anyone know if this can be adjusted out by loosening those screws and maybe a few "tappy tap tap's" to get it flush?
Thanks guys... furious!
Learner plates.
 
So I've removed that section and found 2 alignment pins, they are threaded in and you can see them offset 45* to each other (holes in the top) that go into the casting below... I believe they are out of square to the rest of the way. So do I lap out the holes to move it into position or just remove the pins... hmm. The clamping force from the bolts is insane, I'm thinking of taking the pins out... thoughts? I'll call the shop that sold it to me first but still...
 
It is hard to say without seeing the parts but could it be as simple as a burr or bit of dirt on the mating surfaces?
 
Here is the casting and the pins. Man they are in there, I might drill the casting or try to get these pins out...
I think the bolt force should be enough to hold it. Thoughts?lathe bed 2.jpg
 
that looks filthy, I would clean and deburr really well, make sure there is no paint where it shouldn't be. I expect you will find they fit it before painting and then got paint into some place it shouldn't be.

Luke
 
Bed gaps are notorious for being slightly misaligned .....Id leave out the dowels,if absolutely necessary ,and square it up and tighten......Do you need to frequently remove the gap piece?......Incidentally,bed wear develops quickly at the joint ,as swarf infiltrates the area...........the AL960s are a good lathe ,and I' d buy one .
 
Agree I would clean and with new fresh hard hone stone feel all the surfaces to see anything high, bugged, or a pulled screw thread and correct that. perhaps a long dowel? If your test show raising the gap would correct then I would try to raise it by shimming half of what to error is (perhaps .002 in your case.)
Outboard of the /a chuck you may be on the solid ways and so you may consider a turned chuck running center for high precision between centers work. or out of a 4 jaw, agree that does not help an in-the-taper center or collet run parts.

You might blue the gap and feel it to the bed just to see if it fits down flat and true, and so not distorted with tightening.

You may need to notch the dowels and then use a puller, but I would likely try to avoid pulling them. With everything clean, including the dowels you may fine a .001 (+) or so adjustment at tightening the gap hold-downs by a soft hammer bump.

You might rig a long reach indicator to your saddle and travel up to feel the gap to the solid ways so to know what way to go with it.
 
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You said you bought it new? It should be under warranty. I'd tell the dealer to come pick it up and bring you another one. You go mess the gap up and your warranty is void then you really have to fix it on your own. At least under warranty, if the dealer messes it up trying to fix it, they would have to replace the lathe.
 
So further to this, I spoke with the dealer that is talking to the importer. I measured the gap block and it measures in at 19.06 where the bed only measures in at 19.00. With the alignment pins in it runs out with visable light under a straight edge. I think this lathe is just bodgey as F***. I'm waiting to hear from the manufacturer because as far as I'm concerned I should get a new lathe. If not I will fight for this.

Problem is to get it to true I'm going to have a rather big gap in the V-way. Its not square. Jeebus.
 
Maybe they moved production to mainland China and didn't bother to mention it.
good luck with the supplier, I am surprised at the quality problems, I would expect better from Taiwan.
 
So further to this, I spoke with the dealer that is talking to the importer. I measured the gap block and it measures in at 19.06 where the bed only measures in at 19.00. With the alignment pins in it runs out with visable light under a straight edge. I think this lathe is just bodgey as F***. I'm waiting to hear from the manufacturer because as far as I'm concerned I should get a new lathe. If not I will fight for this.

Problem is to get it to true I'm going to have a rather big gap in the V-way. Its not square. Jeebus.

The gap between the bed and insert doesn't matter. You have to assume the bed and the insert were ground at the same time, so it can be made right. It may take a while to get it perfect, and I'm sure you could do it.

Before I decided to fight to get a new lathe I'd fix the problem. Faster and simpler then getting into a fight that could take a while to resolve. And who wants to be in a pissing match when they'd rather be enjoying the lathe?
 
If the gap insert is high to the bed then a good grind shop should be able to get it to +-0005 or better.
If it is not hard a scraper hand can make it near zero.
* Agree the manufacturer/warranty should make it right.

I don't want the job but could do it on my 618 with accurate mapping the error + in 4 places, dressing a wheel to the angle, shimming the part to match the mapping numbers, and grind.
If I was a lathe vendor, I would know a grind-shop that could do the job. Likely I would know a shop that could make it higher if that was needed.
(One can set/clamp a slide dresser right on the way insert and dead match the angle.)
*If not too much stock scraper hand could scrape the set pad or the bottom of the insert.
 
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So i've spent all day inspecting and messing with this. Finally running a mic down the V bed on the side closest to me. It's 0 all the way till about 2 inches from the gap, then shoots out 0.05mm. Within 2 inches. I've never seen anything like it... I recorded a video and sent it to the vendor. I think the problem is before my gap. The carriage pulls out dramatically on the way before the gap even starts. The taper is about 0.04mm within 20mm on cutting... holy crap. Think I'm up for a new lathe, don't think it will buff out.... any other suggestions?
 
I’m of the school that deburing a gap is bad if the bed was ground with those burrs in place! If the gap and bed were scraped then yes stoning would be ok. Cleaning is cool stoning is not.

We had a guy remove a gap, stone it and reinstall it with out thinking through he was doing. I checked the gap, it was a half thou low and the lathe cut a taper. The machine was never the same. From that point on I’ve never removed a gap, we had a different machine that’s gap was in it’s virgin mating so I bondo’d the SHCS’s over so no one touched it.

So your gap is out and your lathe is cutting a taper, time to play detective.
Clean the gap, and tighten the mounting bolts. Place an mag base with a good test indicator on the main way and slide the carriage towards the chuck. Map the rise, fall, pitch, yaw, and roll. Once that is all mapped out you may have a good picture of how the bed is twisted. You can then start to think of corrective action. Sometimes you can alter your tightening sequence and get close or you may use some onion skin to correct a low corner. Perhaps pull the pins out and tap the gap into position. The pins could be bent.
 
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Is it just the way I am looking at it ?
It seems that your indicator point in the video is on the flat side and not on the V top side where the saddle is riding on the bed.
If so, and a non-critical surface it may have +- .005spec.

Same test but on the V would be interesting.

Ref photo #29: https://www.machineryhouse.com.au/L237D
 
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Grinding the bed with the burrs in place ? Send it back and get one made by somebody who knows what they’re doing.

Regards Tyrone.
Tyrone, you would be shocked at the careless manufacturing techniques employed by some firms. I feel we loose a bit of quality each year as we demand cheap machines.
 
Tyrone, you would be shocked at the careless manufacturing techniques employed by some firms. I feel we loose a bit of quality each year as we demand cheap machines.
Quality costs. Somebody once said to me “ You‘ll remember the quality when you’ve forgotten the price “.

First thing I got hammered in to me as an apprentice was the importance of proper de burring. I took a job to the instructor that I thought I’d de burred. He said “ Are you happy with that son ?” I said “ Yes “.
He took my right hand in his left hand and ran the component down the back of my thumb. It drew blood. “ Are you still happy ? “ he asked.
I can still see the small scar after 50 years.

Regard Tyrone.
 








 
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