Thread: CDCO chuck

Hey Bruce,

Have you ever checked the accuracy of your Tools 4 Cheap 3C collets?

BT

Originally Posted by Anorak Bob

Hey Bruce,

Have you ever checked the accuracy of your Tools 4 Cheap 3C collets?

BT

Bob
Very kindly, a little while back RayG sent me a Federal tenth thou dial indicator.
Its been used extensively to go over all my tools.
I just went & checked the 3C collets after a check on the 4MT to 3C collet adaptor that I ground internally to true it up after purchasing from Hercus.
Anyway, all looks good
Heres the results of a few sample collets checked....
1/4"dia one to two tenth thou out.
5/16"dia two tenth thou out.
1/2"dia zero to maybe one tenth thou out.
When I ordered these collets from Tools 4 Cheap USA, I did ask about accuracy but they would not give any figures.
I think a big contributor to getting accuracy is to have the insert that fits into the Morse taper accurate, this helps obviously to reduce error. Also to fit into the "Same location spot", each time.Ive got a mark on the insert accordingly to negate error.
Just a week ago I purchased a 3MT to 3C adaptor from Tools 4Cheap & ran an indicator over it, there was hardly a flutter on the needle, could not measure any error.
This particular adaptor although ground is not in the hardened condition & has to be treated with a little care. At $25 however, good value, & will be used in the Hercus model O mill
regards
Bruce

Just checked the 3/8' collet & it comes in at one tenth thou runout.
Bruce

Bruce,

I thought I'd undertake an investigation of the accuracy of my rag tag collection of 3C collets. The results are inconclusive.

I have 0.00008" spindle run-out on my '69 ARL. Hercus's permissible error for spindle taper run-out at the spindle nose, back in 1970 as per the inspection record for AR 12930*, was 0.0003". I have two 3 Morse to 3C adaptors. The best I can manage is 0.00005" run-out .

The new, just out of the box, Hercus 13/32 and 5/32 round collets reveal appalling runout, about 0.001" when I measure off both a Sutton drill shank and a Spellmanco transfer punch. Manufacturing tolerances could influence the TIR readings.

The best result I acheived was from a combination of a 1/2" Schaublin collet and a precision ground gauge pin ( a kind gift from C-47 ). 0.00004 " TIR.

What do you use as test bars?

BT

* from test results printed in the Hercus 9 inch lathe sales brochure of May 1970.

I use centreless ground Dowels, made at good old "Amalgamated Wireless of Australia,"
AWA... from my apprentice days.
These are hardened & ground to two tenths oversize. They made large batches of these on a Cincinatti Milacron Centreless, a massive machine.
Perhaps, centreless ground HSS round toolbits could be another possibility, or even machining up some test pieces, from steel.
Just checked the lathe Inspection Certificate of Aug 1990 that came with the Hercus Lathe & it shows a runout of headstock spindle of 3 ten thou. .0003"
I think by fitting in the 4MT to 3C adaptor into the same location each time I perhaps minimize the cumulative errors, if that makes sense ?
I do not have anything to measure to the decimal places like you have mentioned.
Even with the gear I have, I find I spend too much time fiddling around chasing what is probably getting a bit too accurate,but it is addictive.
Your lathe looks to be in pretty good condition.
regards
Bruce

Originally Posted by Abratool

Your lathe looks to be in pretty good condition.
regards
Bruce

One previous owner Bruce, remember, the bloke had headed off to a nursing home...

When he was with it he should have had more brains, well maybe more practical sense, he was a QC. He had broken a tooth off the bull gear and used a steel faced hammer to remove the spindle. There was mushrooming of both ends of the spindle. If you look at the first photo you will see a brighter section at the front of the taper. I set up a Dremel on the tool post and ground away the damage that had prevented the installation of a taper. I turned the damage off the rear end of the spindle on my '58 Model A. Handy having more than one lathe.

The bed has a fair bit of corrosion damage, the result of being covered in saw dust. The QC used the lathe for woodturning. Wood and oil are not a great combination especially when a mixture of the two had set on every surface of the machine. I had to use some nasty stuff called Goof-Off to remove it. Unprotected breathing while using Goof-Off, in the amounts required to remove the dried mess, would kill you.

A still with it ( to some extent ) BT

Originally Posted by Anorak Bob

I had to use some nasty stuff called Goof-Off

How apt.

Apt that I'd be using the stuff?

No. Apt that you used Goof-Off to get rid of the Previous Goof's misdeeds.