ER32 Adapter(purchased)

[DaveH]

Andy,
That's good.

DaveH

[Rickabilly]

(02-04-2013, 12:29 PM)b4dyc Wrote: I have spoken to the supplier and they have asked for it back so they can give me another.

Now that was a good idea

How did it pan out?

Regards
Rick

[b4dyc]

I forgot to add the outcome here
I sent the old one back and they tested it and said it was ok on their myford?
He agreed that the way it was tested was ok. They said it was because my threads were probably worn on the spindle?
I thought the register was what dictated the accuracy, not the threads.
Anyway, I had them send me a morse MT2 adapter as a swap. I will eventually make my own and then i guess it will have to be spot on :)

[Rickabilly]

You are right, the threads mean next to nothing, it's all about the spigot and register face, from what I have read above, the odds are that the bore that locates on the spindle spigot was oversized by four or five thou, of course the shop'll never admit that, at least not in writing, on the bright side, the morse taper version is probably much more adaptable and so more useful for a "Junior Swarf making student" you can use it on a mill, drill press, headstock, tailstock, on anything that takes morse taper which is pretty much any machine tool...

Thanks for the update

Regards
Rick

[Rickabilly]

This is a perfect example of the dramas associated with mass production of heat treated components.

There is a simple explanation as to why the threads are pretty much always sloppy on these hardened steel collet chucks.

The reason is that as the threads are cut prior to hardening they need to be cut oversize, then the register faces and bores are ground after hardening.

As a result if the spigot is accidentally ground oversize, then the irregular thread always pushes the chuck to one side taking up all the clearance resulting in an offset of twice the clearance.

There you go, text book combination of production errors resulting in a part failing to meet specification, the upside is understanding these errors better means we can avoid them

[b4dyc]

Thanks for the explanation :)
I do have a lump of steel that looks like it has a ER32 holder in it
and I have watched Daves (DB) videos of making one but dont like the thought of the internal thread yet. However, I have made a Harold Hall dividing head, so have made a register and male thread :)

[aametalmaster]

That's why when i get inquiries to buy one of my custom made ER-40 collet chucks i won't sell them. Because i like to fit it to the lathes spindle that it will be run on. Now if i went to the guys house and used his lathe it would be different but i can't do that for every chuck :) But i would love to try...Bob

[dallen]

(08-24-2013, 09:28 AM)b4dyc Wrote: Thanks for the explanation :)
I do have a lump of steel that looks like it has a ER32 holder in it
and I have watched Daves (DB) videos of making one but dont like the thought of the internal thread yet. However, I have made a Harold Hall dividing head, so have made a register and male thread :)

Andy the worst that you could do is get it right the first time and not have to do it over again,