Thread: Taster, Arbors and Repeatability

Hi BT,
Is that last picture after the arbour was in the blued spindle?

Time to practice you taper turning.

Stuart

Not sure if the arbor you turned down was new or 2nd hand,but looking at the photo you show of the arbor you can still see machining marks in it,it doesn't look as if it has been ground.

If it is something that someone has made they might not of had it ground.

You should be able to set it up and grind it yourself,you may need to remove a little material from near the drive lugs.

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Originally Posted by pipeclay

Not sure if the arbor you turned down was new or 2nd hand,but looking at the photo you show of the arbor you can still see machining marks in it,it doesn't look as if it has been ground.

If it is something that someone has made they might not of had it ground.

You should be able to set it up and grind it yourself,you may need to remove a little material from near the drive lugs.

It is a second hand arbor Peter and there is no evidence of grinding. I don't know about me, the Dumore tool post grinder and the chance of a good result. Been elusive so far.

Originally Posted by Stustoys

Hi BT,
Is that last picture after the arbour was in the blued spindle?

Time to practice you taper turning.

Stuart

The final photo shows a whisper of blue on the arbor indicating only a ring of contact.

Taper turning wise I reckon you could get away with a whisker of imprecision with say a saw arbor or end mill holder but there's no latitude with something that demands repeatability.

I could buy a boring head arbor and try my luck at boring it out. I encountered the toughness of CTC's steel a while back when I tackled the task of modifying one - https://www.woodworkforums.com/f65/sq...5/#post1403560. I would at least have an accurately ground taper.

BT

What are you saying Bob, just when you think you have gotten away the Spanish will turn up?

I was just looking at the Taiwan tools site, they have arbors that may be short enough in small sizes, you would just have to open the bore up.
Taiwan Tools:Tooling System/Cutting Tools-Milling Machine Tool Holder,Sidelock End Mill Holder,CNC Tooling system cutting tools,Collet Chuck Boring Bar,Milling Cutter,Lathe turning tool holder

Otherwise someone with a cylindrical grinder or TPG...i would offer to try but still waiting on El Gregor to get back to me about the waldown. No guarantee i would get it right either......

Cheers,
Ew

How bad is it dimensionally Bob? Is it a matter of a few 10ths on the diameter or more than that? Is the taper straight or does it flare slightly at the end there?
If you wanted to send it to me I could put it on the lathe and using the taper turning device re-cut the taper if it was a decent amount out, but if it is close then mounting it in the lathe and using some emery strip and/ or a file may be enough to tickle it back to where you want it. That it's not hardened should not matter for the use that you want to put it to provided that it is accurate.

Michael

Bob, you've got nothing to lose by having a go, and experience to gain. Since it's only for an indicator you could relieve most of the taper and just have a contact ring at each end. Then it would be easy to fine tune with emery. Or a scraper?

As above.

Failing that, how about you make one of these?
https://www.woodworkforums.com/attach...24-medium-.jpg
The taper could be very short. Much like a cam loc spindle. Then you could put the taster as far into the spindle taper as it will go.

Stuart

p.s. assuming it wouldn't be to painful to fit and remove.

I pursued the easy, lazy option. I decided to convert one of my CHINESE collet chucks into a Taster arbor. The steel CTC use is pretty tough stuff. A 6mm deep wide cut slowed the 2 horse motor down. Less greed with the feed and I ended up with a nice finish using Kennametal KC5010 grade high positive rake inserts on both tools.

I've gained an additional 18mm of Z clearance and I have a wall thickness of approximately 2mm at the bottom of the bored hole. The only trick now is the position of the grub screw. To engage the existing flat on the Taster's arbor would mean positioning the grub screw on the taper. A brass tipped screw, located in the drive key slot and bearing on the round section of the arbor would probably do the job. I need to think about this.

BT

If you post a picture the rest of us can think with you.

Originally Posted by Bryan

If you post a picture the rest of us can think with you.

I had better change my comment about the finish. The photo of the bore shows chatter. 5010 inserts work beautifully when they can CUT. They don't work too well creeping up to a finished size. The wall thickness at the pencil tip is 6.3mm.

BT

Originally Posted by Anorak Bob

I pursued the easy, lazy option. I decided to convert one of my CHINESE collet chucks into a Taster arbor.

Hope you checked this one for runout *first*.......

PDW

Peter,

This one was one of my frequently used chucks before I chose to give it a change of life. I did check its fit in the spindle, bug snug unlike the previous arbor. I installed the old arbor to check the fit and it actually rattled. I had simply assumed it was ok previously and given that we all know assumption is the mother of all .... ups, I should have known better.

Bob

Originally Posted by Anorak Bob

To engage the existing flat on the Taster's arbor would mean positioning the grub screw on the taper. A brass tipped screw, located in the drive key slot and bearing on the round section of the arbor would probably do the job.

Hi BT,

You aren't thinking about inserting and removing the arbor and Taster separately are you?

Stuart

No Stu,

A one piece ensemble. The Taster arbor would be locked inside the 30 arbor then carefully adjusted for concentricity and there it would stay ( with some finger crossing and a decent grub screw ).

Bob.