Thread: lathe alignment

wouldn't a dti at each end show 0.00 on both ends with it being relative to the saddle? as the saddle moves it moves with the tapper? finish was i would say ok doesnt feel rough.

the lathe was aparently hit into a wall when lifting, theres a bit of a story behind it, basicly the bloke i got it off got it from one of his close friends who used ot to build small brass steam engines, (can tell from the brass shaving everywhere) he then developed alzheimer's and no longer could use the lathe so he sold it to the bloke i got it off who managed to wack it into a wall during transport. he never used the lathe, or got the time to repair it so he sold it onto me.

Originally Posted by brendanh

wouldn't a dti at each end show 0.00 on both ends

Well it should, if it doesnt, thats going to be the first thing you need to look into.

Stuart

Originally Posted by Stustoys

Well it should, if it doesnt, thats going to be the first thing you need to look into.

Stuart

ill give it a go.

Originally Posted by casjon

The horizontal allen head at the rear is for headstock adjustment - I wouldn't be touching it though, at least not until you have checked everything else. Adjusting it before you are absolutely, positively sure that everything else is spot on will only compound your problems.

Isn't that the front / rear bolt, you can make out a chuck / face plate in the photo?
The only the Chinese Ninja master craftman can only adjust this rares its head again.

Originally Posted by casjon

will only compound your problems

The machine has been dropped on it face, Its not the end af the world, if you can adust it, surely you can get it back to where it was, if you can read a micrometer or dial test indicator.
I'd remind you again, this guy is talking about 0.73mm per 300mm. The head stock alignment if stuffed.

Originally Posted by Stustoys

Well it should, if it doesnt, thats going to be the first thing you need to look into.

Stuart

You need one word. "Back" Indicator placed where the tool tip is, just shows the flight of the tool tip. In a perfect world that shoud be zero- zero. Tool tip has just travelled the same as the indicator. To find the error DTI has to be on the back of the work.

You have to subtract tool side errors (Part deflection), via rear side errors (Machine Geometry)

None of which matters, This bloke has 3/4mm per 300mm. That aint bed level, it aint tool pressure. Simple matter of this machine being slapped on its face.

Originally Posted by Stustoys

Well it should, if it doesnt, thats going to be the first thing you need to look into.

Stuart

You need one word. "Back" Indicator placed where the tool tip is, just shows the flight of the tool tip. In a perfect world that shoud be zero- zero. Tool tip has just travelled the same as the indicator. To find the error DTI has to be on the back of the work.

You have to subtract tool side errors (Part deflection), via rear side errors (Machine Geometry)

None of which matters, This bloke has 3/4mm per 300mm. That aint bed level, it aint tool pressure. Simple matter of this machine being slapped on its face. He has to fix that surely, it not like its a little bit out.

Originally Posted by Machtool

You need one word. "Back" Indicator placed where the tool tip is, just shows the flight of the tool tip. In a perfect world that shoud be zero- zero. Tool tip has just travelled the same as the indicator.

Exactly.
Just to explain my thinking. On 40mm bar over 300mm I was thinking we could be seeing some deflection.(given I have no idea how well ground the tool is). Hence the check on the front. It's a quick enough test. If its 0 0 off we go.

Do you think the measured taper is valid with 100mm of the carriage is hanging over the gap?(not on the gap)How wide is the carriage on a 960..

But having said/asked the above....... if you're going to call it headstock alignment I'll happy to take your word for it.

Stuart

Originally Posted by Stustoys

Exactly.
Just to explain my thinking. On 40mm bar over 300mm I was thinking we could be seeing some deflection.(given I have no idea how well ground the tool is). Hence the check on the front. It's a quick enough test. If its 0 0 off we go.

Test on the front / tool side should be zero - zero. Test it with an indicator, that will show you tool deflection.

Originally Posted by Stustoys

Do you think the measured taper is valid with 100mm of the carriage is hanging over the gap?(not on the gap)How wide is the carriage on a 960..{

No way known if it's flapping in the wind. I'd have the gap In. But we are talking about more than 0,73mm per 300mm, Thats fairly ratshit. If it could shoot bullets, it would cripple the guy beside the guy that pulled the trigger.

Originally Posted by Stustoys

But having said/asked the above....... if you're going to call it headstock alignment I'll happy to take your word for it.

Give me a 60t press, I'd be hard pressed to put it out that much. I'd remind every one, this machine has been Flipped on it's face. And the only picture offered up, has it sitting on flat ways.

On the one photo / bolt we have gotten so far, you could point that head anywhere.

Originally Posted by Machtool

Test on the front / tool side should be zero - zero. Test it with an indicator, that will show you tool deflection.

Yes, tool deflection is exactly what I wanted to see.

Originally Posted by Machtool

No way known if it's flapping in the wind. I'd have the gap In. But we are talking about more than 0,73mm per 300mm

Give me a 60t press, I'd be hard pressed to put it out that much. I'd remind every one, this machine has been Flipped on it's face.

On the one photo / bolt we have gotten so far, you could point that head anywhere.

Fair enough.
So Whats next? get the gap back in, repeat test, if still the same recheck level then start moving headstock?

Stuart

on edit

Originally Posted by Machtool

Thats fairly ratshit. If it could shoot bullets, it would cripple the guy beside the guy that pulled the trigger.

Originally Posted by Stustoys

.
So Whats next? get the gap back in, repeat test, if still the same recheck level then start moving headstock?

This is what I'm trying to say. He's not 0.07 0ff. He's 0.73 mm off That used to be close to 3/4 of a millemeter off.

Best practice, he only has 15mm lands on this two journal test.

Move the head, it was face slapped.

I think I might be getting your point lol

I'd agree with that, with one big however: the machine has had a pretty hard life by the sound of it, all the crap under the gap, broken wheel, chipped carriage, missing gibs would attest to that. I was trying to avoid getting the OP jumping in at the deep end. I think he should start at the begining, sort the machine out first, even if it's just a simple clean and adjust gibs, then run the checks. No point in resetting the headstock, if there are other problems that should be resolved first. simple to complex always seems to work best.

Hi Guys,

I'm no expert, but if I was trying to see if the headstock was not square to the bed, wouldn't running a dial indicator across the face of the chuck, with the indicator mounted on the cross slide show it ?

Not necessarily. You are assuming that the surface you are running on is square to the spindle and that the cross slide is square to the bed. Usually this is not the case as manufacturing tolerances are arranged so that in use the lathe will face off, any "errors" accumulating to give a concave surface (if only very slight).

I'm with Phil on this one - because the lathe has been dropped, it is quite possible that the headstock has moved. It really depends on the force of the blow and the quality of the materials the lathe has been made from.

Michael