Thread: Dead Centre Size for Hercus Spindle

Not sure but I think that they supplied the Spindle with either a M/T3/2 sleave and M/T2 Centre or M/T3/1 sleave a M/T 1 Centre.
I have just checked mine the latter of the 2 above and also a M/T3 Dead Centre.
The M/T3/1 is 1 9/16" from Spindle End,with Drive Plate 1 1/2" from the Face,with Face Plate 1 1/4" from Face.

The M/T3 is 1 13/16" from the Spindle End,with Drive Plate 1 3/4" from the Face,with Face Plate 1 1/2" from the Face.

The distance that the Centre sticks out doesnt matter as long as you have a dog that will reach whatever you are using to drive it,or if the Centre is out that far that you can machine the desired length you wish.

They came with a 3 to 2 MT sleeve and two MT 2 taper dead centres. I just turned up my own centre, using the top slide, which is soft so that I can true it up if I want to do anything particularly accurate. I made the MT a little short because the top slide doesn't travel quite far enough. If you're keen you can buy a reproduction of the original sleeve here for $15 US.

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Pipeclay: Sounds like yours stick out as much as mine do. It just seemed like it was too far. One of the dogs I have has a 25mm return arm so that means I would have to have a standoff from the catch plate of say 30mm for things to work.

Blackfrancis: I had a root around in my goodies boxes this afternoon and found 3 MT3/2 adaptors and a couple of MT2 dead centres. Tried all sorts of combinations. Some worked out longer, some slightly shortly. Even found a MT3/1 and short MT1 dead centre. That produced the shortest combination but is unusable as I have no way to eject the dead centre.

Also had a look at buying a MT3 blank but that doesn't work out too cheap when you add postage into the equation. As you've said I think I'll turn up my own MT3 blank so I can get the length down a bit more. Ideally I'd like about 15mm-20mm hanging out from the catch plate face.

Why dont you either Weld an extension to your Drive Dog,make your own Drive Dog,put a bolt through the Slot in your Drive Plate or Drill and Tap you Drive Plate and put a bolt in to drive your Dog.
Making your own M/T3 is ok you can do it on your machine with the Compound you just need to do it in 2 steps with the Compound,the only problem you may find with using a M/T3 Dead Centre that you make may occur if you dont Harden it,you may have to continually turn the point.
Is there any reason why you are so concerned about the Centre being out so far.

Originally Posted by pipeclay

Is there any reason why you are so concerned about the Centre being out so far.

No concerns I could fully justify Most of the problems are probably with the idiot behind the tool.

I've tried turning between centres before using a face plate because I didn't have a catch plate and I've always had troubles with having so much overhang and getting dogs to engage properly. Most of the stuff I've tried turning between centres would be less than 20mm dia. I recently got a catch plate thinking this would solve the problem but it hasn't.
I think the whole thing probably boils down to I don't have the necessary set of tooling/clamping bits and pieces made up for between centre turning so I try and cobble things up. I think it might be time for me to make up some T-Nuts, studs, posts, dogs etc for between centre and face plate turning.

Have you ever thought of placeing a piece of stock in your 3 or 4 Jaw chuck and Turning a Centre up and using your Drive Dog to run off your Chuck Jaw.

Originally Posted by pipeclay

Have you ever thought of placeing a piece of stock in your 3 or 4 Jaw chuck and Turning a Centre up and using your Drive Dog to run off your Chuck Jaw.

Yep. Tried that one just recently. I'm in the process of building Jerry Howells Miser Stirling Engine and I used that method to turn the main column. The column has a square 25mm section at the bottom so I threaded a dummy stud into the base so it would catch on one of the jaws. Again using the standard centres it would have been sitting out from the face plate by miles and I thought that for such a small part I must be doing something wrong.