5c collet chuck alignment

[Ian PParticipant @ianp]

Steve

I'm glad you have no got a system that is working properly but your last posting has got me wondering what was the real cause of the error.

I dont understand how or why the Axminster DTI should indicate errors that do not show up on another device. In principle for testing concentricity the DTI does not need to be calibrated or even high quality, it just has to be repeatable and have a indication range relevant to the purpose.

On your original tests with the Axminster gauge, when rotating the spindle did the needle oscillate over the same markings consistently each revolution?

Ian P

[Steve Cole 1Participant @stevecole1]

Hi Ian,

In answer to your question i forgot to add that i had to do some slight tapping with a copper and hyde knockometer, When i clocked it with the Axminster DTI in the nose is was about 0.02 out, taking into account the 0.03 i was getting on the silver steel i figured it was part down to alignment and part down to the silver steel. As you saw on the photo with the two clocks inline you can see it was +0.03 on one and -0.03 i decided to put the Axminster DTI in the nose and tap until i got it down to 0.01 the problem i then had was as if the DTI had to settle back down? Almost as if the tapping had caused it to un settle, in addition the bezel is very tight so when i tried to turn it to zero i would move the indicator slightly and its would screw the reading. I kept going until i had it sort of repeating but then for no reason it would shift/ jump about 0.01? It would go between 0-0.01 then jump to 0.03-0.04 then barley move then go back to 0 which made me doubt the clock as it just wasn't repeatable at any point. I even marked the chuck so i had a basic reference to go off. I then tried to put a plunger in at an angle and that barley moved but it wasn't ideal however it did give me a better indication that things were running as they should be. It was only when i put my new indicator in there could i then prove it was true. The problem i had was the in accuracy of that Axminster one, it was almost as if it was picking up something on the surface even though the surface was smooth.

I think i would mainly put to down to the indicator and silver steel. Initially it got me close enough but for that last bit of certainty i needed something that hopefully would give a more accurate reading.

Hope that made sense

Steve

[Steve Cole 1Participant @stevecole1]

[Nick_GParticipant @nick_g]

Posted by JasonB on 22/01/2016 20:28:44:

If you want to make a rocket to take you to teh moon then maybe you will want more accuracy

.

I would have thought that destination planet Zanussi would have been more fitting to your age group and desire.

.

Nick

[JasonBModerator @jasonb]

Posted by Michael Gilligan on 22/01/2016 21:30:56:

Nicely corrected, Jason

As a matter of interest; how bad was it before you worked on it ?

[that is, after all, what the supplier was selling]

MichaelG.

Can't quite remember but could probably knock a zero off so maybe 0.005" and not true to the axis of the lathe either which is why I skimmed the back as well as doing the inside edge of the recess.

Good result Steve, look forward to seeing that rocket

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Steve Cole 1 on 21/01/2016 20:28:18:

Thats as far back as that particular collet goes Jason, I will have to check the others? I assumed that was normal? Its a Warco collet chuck and the collets were from RDG…. Not sure if that makes a difference.

.

Steve,

Just going back to Jason's observation about yout 1/2" collet, and ^^^

It might be worth checking the keyway dimensions in your RDG collets.

… useful dimensioned sketch on this page.

My reason for mentioning it is that I bought BCA adapter from RDG on which the keyway was just a little short [they use a Horizontal Mill to cut them] and the key 'digs-in' before the taper seats properly. It is currently of ornamental use only; but I will get around to extending the keyway someday.

Glad to see that it's all going well … and thanks for the link to Midland Metrology

MichaelG.

Edited By Michael Gilligan on 23/01/2016 08:09:21

[JasonBModerator @jasonb]

It is currently of ornamental use only; but I will get around to extending the keyway someday.

So that's how the ornamental turners get all those eccentric patterns in their work

 

Seriously I wonder it it may be the pin that is at fault as the 1/4" collet is out even further? But with that amount of protrusion I would not have expected it to engage the tapers. Maybe they have started making them with an undersize taper to allow people to regrind them

 

Edited By JasonB on 23/01/2016 08:22:49

[Michael GilliganParticipant @michaelgilligan61133]

Posted by JasonB on 23/01/2016 08:19:44:

So that's how the ornamental turners get all those eccentric patterns in their work

.

[Swarf, Mostly!Participant @swarfmostly]

Hi there, Steve,

Just a suggestion: Take your plunger-type dial gauge in to your friendly metrology emporium and ask them if they can supply you with an 'elephant's foot' tip for the plunger. (The ball-end tip should unscrew to allow other tips to be fitted. ) The flat or 'elephant's foot' type has the advantage when 'clocking' round stock, especially small diameters, that you don't need to present the probe so precisely to the job.

The reason I suggest taking the gauge with you is that there are two standard screw threads, metric vs unc. so it's good to be able to 'try before you buy' !

Being able to visit the emporium gives you the great advantage that the cost of the extra tip won't be swamped by P&P costs and the transaction won't be burdened by the minimum order charge imposed by some tool suppliers.

Best regards from my armchair,

Swarf, Mostly!

Edited By Swarf, Mostly! on 23/01/2016 11:18:22

[Steve Cole 1Participant @stevecole1]

Jason i think you have hit the nail on the head. I checked the collet as you suggested Michael and and everything is with in the dimensions posted. I then tried the 1/2" collet in the chuck and tightened without any stock. I then placed the silver steel in and tightened and this is the result

[Steve Cole 1Participant @stevecole1]

Also thanks for the advise "Swarf, Mostly!" when i go over to drop the pin gauge off i will take my clock with me and see if they have a set of tips, I think i remember seeing them whilst i was there?

[Chris Evans 6Participant @chrisevans6]

I have had a few new 5C collets that required the key way to be extended. At less than £5 a time I can live with that as it is only a few moments on the mill to correct them.

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