- Joined
- Nov 23, 2020
- Messages
- 820
Looks like I am cutting a 1.5 thou taper over 6”. Let the fun begin
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A head scratcher here …
- Thread starter poorboy
- Start date
Just did a facing cut .. almost no difference from to back (.0001-.0002 over 3") - so I am guessing that my gear head alignment is fine. Even though I used a precision level - doing the two collar test - I still have a .002 taper (the largest is towards the chuck). Im guessing that my ways are still slightly twisted.
What a pain in the ...
What a pain in the ...
- Joined
- Feb 21, 2022
- Messages
- 846
Try locking the compound slide and leaning lightly on the toolpost pushing the tool into the bar when taking a cut. This will take out some slack in the setup, if this cuts without a taper then it is slack in the lathe ways. If it still has a taper then you can disregard this. It is a quick test to eliminate one potential issue.
- Joined
- Oct 7, 2020
- Messages
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I adjusted my lathe with a precision level, without changing anything the next morning it was off a little bit. Readjusted it, tightened the lock nuts and it's off again, only just a tad so I called it good.
- Joined
- Apr 14, 2014
- Messages
- 3,515
The attached document may help you find your problem. It's a copy of the inspection sheet that came with each Sheldon lathe. The graphics show what instruments were used and where they were placed for each measurement. The text describes the acceptable range for each measurement. The right column is for recording the actual measurements on each machine.
I had been looking at these but when I saw they were made in 1ndia I retreated. I have gotten some of the worst quality junk from there. But I did just order the MT5 test bar stated to have a max runout of 0.0002”. Thanks for the recommendation David.I invested in one of these - makes aligning the headstock very easy. Once the headstock is aligned you can adjust out any twist in the lathe bed.
Lathe Alignment Test Bar Shank Size 1MT, 2MT, 3MT, 4MT, 5MT, 6MT Hawk | eBay
2MT 283mm (11-1/8”) 0.0002”. 3MT 335mm (13-3/16”) 0.0002”. 4MT 386mm (15-1/4”) 0.0002”. 6MT 507mm (19-7/8") 0.0002". 1MT 151mm (5-15/16”) 0.0002”. 5MT 400mm (15-3/4") 0.0002”. Hawk Werkzeuge comprises of a dedicated and skilled team of engineers with an aim of providing you tools of highest...www.ebay.com
I have ordered one. I will inspect it and report my results here. Advertised TIR is 0.0002”.
I feel your pain. My lathe is cutting tapers too. And I thought I was going to spend my retirement making little steam engines.
- Joined
- Dec 26, 2015
- Messages
- 2,139
These photos and the descriptions that accompany each image might be helpful. I'll be interested to hear your measured run-out on the test bar. I spent $120 for mine hoping that would be an indication of quality, and was rewarded with a very accurate test bar - or perhaps I just got lucky.
Aligning the Headstock of PM-1340GT Lathe
Click the image to see the text description below the photo.
www.flickr.com
Question for everyone, once you go through the headstock/tailstock alignment processes is this something you repeat yearly, etc.? Same with tramming a mill, once it's dialed in, do you need to go back and recheck that periodically or only once you've moved the head, etc..? Wasn't whether this could change over time with using the machine, I'd think over time things can loosen