[4]

Saddle causing .150 taper 3” off chuck no tailstock need help.

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Illinoyance

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Put a magnetic backed indicator against the QCTP and quit worrying about deflection.

BTW, after several hours of adjusting and testing I have my Nardini cutting zero taper over 6" length.
Next, I make a test bar to run between centers and get my tailstock centered.
 

john.k

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Using an angle grinder to fit lathe heads ,and mill parts is quite standard practice on the budget &hobby chinese machines.......but you would expect after a million machine fits ,the assemblers would develop a certain skill set.
 

stupoty

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Hi soooo I was checking out my headstock the other day and realised I have a bit of a taper issue also, I have to dismantle part of the power feed to get at the left hand attachment clamp for my head stock and was amazed to find it lose when I did get to it.

I have this new shinny thing direct from India that I am hopeing will help to adjust it all :)

294721


Nice , (I havnt checked its acuracy yet but from first impressions :) )

Stu
 

Illinoyance

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I a m not a fan of test bars. If the headstock taper doesn't run perfectly true and the test bar isn't perfectly true the results of the test setup are meaningless. I prefer to chuck up a piece of bar or pipe and do the two-collar test.
 

stupoty

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I a m not a fan of test bars. If the headstock taper doesn't run perfectly true and the test bar isn't perfectly true the results of the test setup are meaningless. I prefer to chuck up a piece of bar or pipe and do the two-collar test.
Yeah I was doing test cuts to align but the need to re assemble the power drive between adjustments was making it very very slow going :(

it's old american iron, the tapers fairly good ;)

Stu
 

Cadillac

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Hi soooo I was checking out my headstock the other day and realised I have a bit of a taper issue also, I have to dismantle part of the power feed to get at the left hand attachment clamp for my head stock and was amazed to find it lose when I did get to it.

I have this new shinny thing direct from India that I am hopeing will help to adjust it all :)

View attachment 294721

Nice , (I havnt checked its acuracy yet but from first impressions :) )

Stu

I have that same box must be the same distributor. Mine was accurate. I find useful on many machines worth the 50 bucks in my book. Always good to have multiple ways to verify readings too.
 

john.k

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At least its easy enough to see if the test bar is running true,and maybe even correct any runout.....Even if it doesnt run true,you can still split the difference to get a baseline ,before the trouble of a test cut.This assumes its straight and of constant diameter.
 

stupoty

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I have that same box must be the same distributor. Mine was accurate. I find useful on many machines worth the 50 bucks in my book. Always good to have multiple ways to verify readings too.
It seems fairly good, I have done some examination of it in vee blocks and their was perhaps some lack of conectricity with the taper and the strait part but it could also be a small wabble on my test set up , the strait part seems very strait, I used it on the centers to set up my tail stock to make a aluminium MT4 lap, because it turns out when you have a foot of metal projecting out of the spindle that tiny burr makes a bit of a difference ;)

Do you think the OP will ever come back ?
Can we turn this into a test of how far of topic a thread can go ;)

I think theirs a real opportunity to now turn the thread into a thread on lapping :oops2:

Stu
 

qualitymachinetools

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Hey check this out, some have already mentioned this, but in case anyone needs a visual, look starting on page 31: http://www.precisionmatthews.com/wp-content/uploads/2017/02/PM-1340GT-PM-1236T-11-10-17-V5.pdf
If this machine mentioned is like one of ours, these headstocks are bolted down to the bed on a flat plate, not fit to the ways. They will have some sort of adjustment screws, usually up behind the motor. And if the machine was crashed, it can definitely move this, causing that problem. Sure they are not quite as rigid as the older type like the big american lathes that had the headstock fit to the V Ways, but they are also better because they can be dialed in. I am certain thats your problem, this should get you back up and cutting straight in a few hours.

Edit: I see this thread is older, didnt look at the first dates, but hopefully you are up and running, if not, or if anyone else comes across this, that should help out.
 

john.k

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This is a common problem,and hundreds will look at these posts in the future as reference material........so the OP is immaterial ,many others will benefit.
 
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