A Question From A Lurker...

Perhaps a touch with one of those Dremel-style knife-edge grinding wheels?

Sounds like it to me (and/or the 2MT adaptor is cut loose). I had the same with a backplate I bought to mount a spare chuck.

Regards, Tony

could it be that the registration portion (unthreaded) at the rear of the chuck is a different bore than that needed for a Myford? Check the spindle's unthreaded portion for diameter then the internal diameter of the back of the chuck. Mike in BC

Sorry, of course I meant the backplate NOT the chuck. Mike

A friend of mine had this exact problem with a new backplate.The diagnosis was a tight thread - the register diameter was spot on. Luckily I had an old ML7 spindle and we lapped it onto that using Timesaver non embedding lapping paste. Ended up with a perfect fit.

Charles

Don't know if this is similar or not but I bought a faceplate for my Southbend from RDG and couldn't get it to fit, it wouldn't screw right on. After some investigation (marking blue to find the tight spots) I discovered that it had a sharp edge where it shouldn't have. I mounted the faceplate backwards and machined a small lead in chamfer on the threaded portion, and it fitted fine then.

Regards

Kevin

Nigel, The consensus is that it's a bit tight. I recently bought a couple of D1-3's off RDG, brand new. He's obviously getting these CNC'd up and these didn't fit the tapered register correctly on either machine. I find them a helpful and good firm to deal with so I just licked these two up and rang them just to point out that their supplier had got things a bit tight. If I had returned them I would have been facing return postage, lost time and the chance I would get exactly the same back. Even having to do 10 minutes work on them, they were still cheaper than I could have got them from elsewhere.

-- Regards,

John Stevenson Nottingham, England.

I bought a "new" ready treaded backplate. It was only a "little" tight so I tightened it up with a bit more leverage.

Needed a tap with the hammer to shock it undone though.....

Then it needed a new backgear because the teeth fell off....

Anyway, I cleaned up the myford threads with a triangular file, and polished up the internal peaks of the backplate with a round one. The problem must be that the bore through these backplates is a little (couple of 'thou) small.

The threads can be a loose fit anyway, as the location is the plain portion of the spindle.

Martin L

For your friend:-

If the bearings are white metal then the mandrel is definitely soft. If the mandrel has been replaced by the newer hardened mandrel with bronze bearings then the threads still seem to be soft ! I would carefully clean the bruised portion of the thread. After that I would work a small amount of engineers blue (not layout blue.. look for Stuarts engineers marking, Chronos have it) thinly onto the threads and surfaces of the backplate with a piece of kitchen towel. after screwing the backplate on I would examine both the mandrel and the backplate to see where the rub was occurring.

Mark Rand RTFM

Hello folks,

Can I hold my hand up? I am "The Lurker". Thanks to everyone for such quick replies. I'll try to cover them below. Please excuse and/or correct any misattributations.

Also, may I say from the word go, that this is NOT a complaint about RDG's stuff. I have been _very_ happy about what I have bought from him.

Airy> Perhaps a touch with one of those Dremel-style knife-edge Airy> grinding wheels?

Don't have one and I really want to use touching up the spindle as a really last resort. As we are always told, removing metal is easy, putting it back on is more problematic.

Mike> could it be that the registration portion (unthreaded) Mike> at the rear of the chuck is a different bore than that Mike> needed for a Myford?

Unfortunately, it doesn't even get that far onto the spindle until it gets too tight to turn.

Charles> Luckily I had an old ML7 spindle and we lapped it Charles> onto that using Timesaver non embedding lapping paste.

OK, so I don't have a spare spindle, but could I try this with the 2MT adaptor? Does it matter that this already fits? How much is a replacement adaptor as the lapping will, I guess, not do it a lot of good? Is fine valve grinding paste OK to use?

Kevin> I mounted the faceplate backwards and machined a small lead Kevin> in chamfer on the threaded portion, and it fitted fine then.

I tried reversing it, and it screws on the same amount.

As JS says, the verdict seems to be a tight thread on the backplate. That's good, as it means the Myford is OK. At worst, I have a chunk of steel that will come in useful some day.

Noone so far has said anything about a spindle nose tap. I've seen, I think, Guy Lautard (sp?) advertising these, but he's too far away. Could someone confirm that the thread is what I think it is (I looked at lathes.co.uk, and the only thing it didn't confirm was the 55 degree thread angle), and advise on the availability and cost of a tap.

Thanks for your time.

John

Personally I'd avoid valve grinding paste since it's a pain to clean out - but then again I've used it on enough engines and always cleaned it out again. The stuff I mentioned is:

BTW where are you - if you're near enough to Suffolk/London I could lend you the said "old spindle".....

Charles

Yes 55 degrees. I have a spindle nose tap for a Myford if you want to borrow it. Where abouts are you?

-- Regards,

John Stevenson Nottingham, England.