MEW 198 Worden ER25 Chuck

The drawing titled ER25 Chuck for Worden Tool and Cutter Grinder shown on page 29 of the digital issue of MEW198 contains a number of gross dimensional errors.

The two views affected are the ER25 Chuck body (central view), where the three external diameters are completely incorrect, both in their inch and metric versions.

The other view is the plan view of the Indexing block where the diameters of the two holes and the counterbore are again completely wrong. For example the dimension of the a 2BA socket cap screw counter bore is given as:

diam 50.32(58.0) where the bracket value is the metric version. 50.32" is obviously wrong! and 58 mm is neither the correct value or a correct conversion of the stated inch value.

Chris

Edited By Chris Courtney on 14/12/2012 12:32:45

Hi There

It looks like the diameter symbol on the original drawing has been converted to 5 in the conversion process.

This affects the top centre drawing and the middle left drawing.

regards David

Yes that makes sense; strange that it hasn't affected all views using the diameter symbol.

Chris

Hi There

Some of the diameter symbols in the original were included with the dimension. Some were offset above or below the dimension.

The problem was with the ones in line.

regards David

For the record, here are the originals (well, exported to wmf and then converted to JPEG).

Clearly there is a minor problem with the conversion from my autocad files. Apart from this though, the magazine version is easier to read than the version I sent David - something I shall learn from. Thanks for reading!

Rod

That was an interesting article Rod, not least as it was interesting to compare with the ER25 holder I made for my grinder. I tighten mine up by hand only, and it has never slipped. I fitted a 12-step ratchet to the back end for easy indexing of tool teeth. I haven't tried sharpening the edge of mills - I tend to wear out the ends anyway! I think that bushing the alloy uprights for the spindle was a bit over the top.

The whole thing is a bit agricultural, but it does the job.

Neil

As David says just cross out the leading "5" on each of the dimensions in the centre drawing only and all is OK.

I did mine last night and was just going to post now but you beat me to it.

Regards Clive

Neil,

I wish my "agricultural" stuff was as neat. I, too, have found that hand tightening is perfectly adequate for holding mills for sharpening.

cheers,

Rod

In the "What did you do today" thread John Alexander Stewart mentioned that the collet nut fouls the table, so the tool holder can't be rotated through a large angle. Having just bought a ball bearing nut from Arc, I had a spare to play with. Although toughened, it can be turned with a TC tip at slow speed with plenty of cutting oil. I turned mine down to 1.53" OD (38.9mm) and it now clears the table. The TC tip coped with the interrupted cut OK but I had to so some de-burring with a grinding point in the Dremel.

cheers,

Rod

Hi Rod;

Was thinking about turning the nut for my version of your ER holder.

But, last weekend was milling away the outline of my Hemingway/Thomas rolls side plates, and my time was spent a) worrying about the CNC mill and b) sharpening 6mm two flute end mills.

Both the CNC milling and the Worden sharpening worked absolutely fine - your ER collet chuck was just the ticket.

Thanks - John.

John,

Thanks for the kind words - it is immensley satisfying to know that someone has found my witterings useful.

cheers,

Rod