Thread: Tailstock Shimming

Originally Posted by Stustoys

Hi Bruce,
How much do you want to spend?
Copy of a Blake.
shars.com - CoAxial Indicator Set
The quauity of them seems to be patchy, I have one that seems ok, DaveJ needed to pull his apart and grind a couple of parts.

The blakes I've seen generally go for around twice that

Then there are Taster and centro
Haimer GmbH - Centro

how about this one for only 3,917.85 GBP?
MeasureShop.biz: CENTRICATOR Centring device

Stuart

I picked up my Taster for about 230 dollars on local Ebay.

https://www.woodworkforums.com/f65/ta...9/#post1432878

I would have thought that the Coax required mounting exactly on the spindle centreline for the thing to work correctly and concentrically.

BT

Originally Posted by Anorak Bob

I would have thought that the Coax required mounting exactly on the spindle centreline for the thing to work correctly and concentrically.

Hope you are wrong BT.
I can see it needs to be parallel to the spindle axis.

Just checked it. doesnt seem to matter. Cant exactly say I have my head around it at the minute but I have to duck of for awhile. I set it up running true with a DTI in a four jaw. Checked on a live center(thought it wasnt turning), got about 0.0005" run out. Offset the four jaw as far as it would let me(only a couple of mm but that would be more than enough to show up a problem I would have thought). Check live center again, still showing about 0.0005" run out. I'll leave you now to get your head around that hehe

Stuart

Originally Posted by Stustoys

Hope you are wrong BT.
I can see it needs to be parallel to the spindle axis.

Just checked it. doesnt seem to matter. Cant exactly say I have my head around it at the minute but I have to duck of for awhile. I set it up running true with a DTI in a four jaw. Checked on a live center(thought it wasnt turning), got about 0.0005" run out. Offset the four jaw as far as it would let me(only a couple of mm but that would be more than enough to show up a problem I would have thought). Check live center again, still showing about 0.0005" run out. I'll leave you now to get your head around that hehe

Stuart

I just did a quick bit of reading. It appears ( to me ) that a Blake acts in a wigglerish fashion. Hence the accommodation of run out. Am I on the right track?

BT

Hi BT,
I think you are up the wrong tree there. Wiggles work by knocking the ball to the center of rotation.

If you think about the coax indicator as just a DTI(which is all it is, just made so the face points the same way). Its measuring the distance from the center of rotation to the surface its running on. Any runout is fixed so the styles(?) still rotates around the spindle axis, just at a different diameter.

Stuart

I'll stop barking and stick with my simple to fathom DTI and vee block set up.

BT

You have me wondering what my TS is like now.....i will try it when i get a chance. I only have a .001" DTI...so i wonder if a setup like Bryans but with my .0001" DI would work

Actually I've been meaning to rig something for a DI because then I could see it the whole time.

Originally Posted by Anorak Bob

I'll stop barking and stick with my simple to fathom DTI and vee block set up.

What? not my best explanation?

Think about increasing the "run out" of your DTI/Vee block set up. The contact tip still moves in a circle, the circle is just bigger.

Talking about your Vee block, what are the two extra thumb screws on the clamp for?

Stuart

p.s. I think I slipped in an extra 0 earlier, I've been testing few things and the tail stock is 0.0005" out front to back but about 0.0035" out vertically

Originally Posted by Stustoys

What? not my best explanation?

Think about increasing the "run out" of your DTI/Vee block set up. The contact tip still moves in a circle, the circle is just bigger.

Talking about your Vee block, what are the two extra thumb screws on the clamp for?

Stuart

p.s. I think I slipped in an extra 0 earlier, I've been testing few things and the tail stock is 0.0005" out front to back but about 0.0035" out vertically

Things have clarified Stu, your explanation is fine.

The side screws on the Starrett 567 prevent tilting when the block is used on its side. Here is a nice new one - STARRETT TOOLS V-BLOCK complete set #567 NEW!! | eBay
Tempted?

What was that you said!

BT

Following on from BT and Stuarts response (thanks to you both) to my version of tail stock aligning using a coax in the three jaw chuck I felt like some more checking out was in order.Reading Stuarts later posts he has done some delving as well. I started from scratch and checked the level of the lathe, it was only slightly out so I adjusted it. I then mounted the four jaw chuck and dialed the coax in.Then made a small adjustment to the tail stock to get it spot on in the horizontal axis. I then swapped the four jaw for the three jaw,fitted the coax and the results were the same as the photos show. Now it gets interesting, I removed the coax and put a 20mm dia aluminium bar in, faced it and centre drilled it with it close to the chuck. I scribed the top of the bar in line with no1 jaw slid it out 150mm being carefull not to loose the indexing and then did two .002" DOC cuts. After measuring both ends 130 mm apart I had .0031" diameter difference, biggest at the tailstock end,quite a surprise. Can anyone see where I went wrong. I then moved the tailstock over .0016" did another light cut and both ends measure exactly the same with my tenths micrometer.
Bob

Indicators only get you close I reckon. Cut and measure is the final test.

Hi Bob,

I'm not sure you should indicate off that surface.
Did you lock the tailstock quill while you were indicating it?
Did you unclamp the tail stock while you were adjusting it?
Did you move the tail stock along the bed between aligning and turning?
Did you lock the quill while turning?
How did you wear a line in a live center?
Did you turn using a live center or dead?
Did you indicate it afterwards?

After all that, what Bryan said.

Stuart

p.s. Very nice BT........ certainly not cheap!!!, I'm not surprised you heard my expletive from over there.

Originally Posted by Stustoys

Hi Bruce,
How much do you want to spend?
Copy of a Blake.
shars.com - CoAxial Indicator Set
The quauity of them seems to be patchy, I have one that seems ok, DaveJ needed to pull his apart and grind a couple of parts.

The blakes I've seen generally go for around twice that

Then there are Taster and centro
Haimer GmbH - Centro

how about this one for only 3,917.85 GBP?
MeasureShop.biz: CENTRICATOR Centring device

Stuart

Stuart
I checked out the price of Shars Coax Indicator.
About US $ 57
Sent them an email on freight cost to Australia.
Got an answer this morning US $ 50
Freight is very pricey !
regards
Bruce

Hi Bryan & Stuart
Thanks for your response, now for some answers to Stuart's questions.
I indicated off both live and fixed centres and the tailstock quill all gave similar results.
Tailstock quill was locked all the time except when engaging into the aluminium bar,locked when turning.I had to move the tailstock rearwards to fit the bar into the chuck the quill was locked during this operation except when engaging it into the centre.I cut the groove in the live centre ages ago to allow acess for my threading tool.All turning with the live centre shown in the photos.I have not indicated after turning, what would that show?
I always check for taper and adjust the tailstock as the final solution, I was just surprised by the size of the taper on the first cuts.
Regards Bob