Slight taper turning between centers

If you're still getting a taper between centers, here's a section out of South Bend's "How to Run a Lathe" on doing a two collar test and instructing to align your tail stock if getting a taper. Have you already tried this? You should be able to remove the taper and turn true between centers by properly adjusting your tail stock. At least get it pretty close, not 0.022" off...

Use mics though, not calipers.

Ted

Two collar test.jpg
 
I skimmed all the posts but wanted to pipe up and say I found that my lathe had a worn TS base from all the decades of use. I ended up shimming mine to raise it up on the quill end and make up the gap between worn bed and worn TS. I had also purchased an import MT3 test bar for my TS in this pursuit. This was a good purchase for me since the tool is useful for other things like setting MT3 tapers on the taper attachment!

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Ok, few updates:

When I can put dead centers up against each other at the headstock, the tailstock center has a visible offset both away from me and above the headstock center.

However, when I use the 12” alignment bar, they’re lined up almost perfectly: dead on left to right and tailstock is 001” high.

So Then I tried cranking the offset on the tailstock 020” away from me. I have a 6” cut I’m working on, and with this big offset, I now see a taper larger towards the headstock as I had before for the first 1”, something flat-ish between 1” and 4”, and then a taper in smaller towards the headstock between 4” and 6”. Shrug...
 
brandon428 said:
Ok, few updates:

When I can put dead centers up against each other at the headstock, the tailstock center has a visible offset both away from me and above the headstock center.

However, when I use the 12” alignment bar, they’re lined up almost perfectly: dead on left to right and tailstock is 001” high.

So Then I tried cranking the offset on the tailstock 020” away from me. I have a 6” cut I’m working on, and with this big offset, I now see a taper larger towards the headstock as I had before for the first 1”, something flat-ish between 1” and 4”, and then a taper in smaller towards the headstock between 4” and 6”. Shrug...
Click to expand...
It is common to have the tailstock slightly higher than the headstock on new machines
As the TS wears, it gets closer to the HS height
The difference is intended as far as I was informed
 
p.s. a chunk of brass is not a good starting point , the brass is out if round, even in a collet.
You might want to try a piece of drill rod or a center drill or carbide drill to be the indicator to start with
 
Ulma Doctor said:
It is common to have the tailstock slightly higher than the headstock on new machines
As the TS wears, it gets closer to the HS height
The difference is intended as far as I was informed
Click to expand...
Yes, and I didn't mention before that I had shimmed the tailstock similar to what Kevin had done when I originally bought this machine. IIRC, it was ~0.005" low, so I added a 0.006" shim because was also told they should be a thousands or two high when they're new to account for exactly what you said.
 
Ulma Doctor said:
p.s. a chunk of brass is not a good starting point , the brass is out if round, even in a collet.
You might want to try a piece of drill rod or a center drill or carbide drill to be the indicator to start with
Click to expand...
I'm using 12L14 tight tolerance steel rod.
 
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