Horizontal milling may be outdated in industry, where making thousands of parts at rock bottom prices matters, but in the model and home machine shop, they are as good as they ever were, and will move metal faster than a V mill!. Arbors are still available new in metric and imperial sizes from Rotagrip or Gloster tooling. I have a Harrison H mill with the optional vertical head, which I rarely use!

I’m still using my shaper to cut plane surfaces quickly. I’m not sure if 1 1/4 is too big for 30 int.
And making aN adaptor to reduce the bore would be a tough gig wouldn’t it? The cutters have to run dead true and I’m not sure an accurate reducer could be made. Correct me if I’m wrong as I’d live to know if it can be done in the home shop. Mick

I bought an INT30 Clarkson Autolock chuck – the bigger one which takes 1 inch shank threaded end mills – and a collet to match at the last Midlands show. Looking at it when I got home, I thought I've got some accurately sized 1 inch BDMS, it wouldn't be beyond the wit of man to take a length of this, thread the one end to match the Autolock collet, and the other end to take a draw nut. Slice a keyway up the side, and now assemble the bits with some spacers to make a horizontal arbour with a ready made ISO30 taper on the end.

I guess if you used a bit of 1.25 inch BDMS as the starting point for the arbour you could do the same thing. The fun would be in keeping the reduced portion which engages with the collet concentric.

Best rgds Simon

IMHO –

There's "true" as in not wobbling side to side, and there's "true" as in not running eccentrically. You want the cutter to run as "true" in both senses as possible. So the ends of the spacers need to be square to the bore, and the bore of the cutter needs to fit with minimum clearance on the arbor. Interference fit isn't a good idea, it's difficult to get the cutters on and off the arbor, so some clearance radially is inevitable, but it needs to be a small amount (sub one thou).

If not you'll get some combination of a cut that's not where it should be, and being made by only a few teeth on one side of the cutter.

HTH Simon

As JS says turn it at one setting and part off. Leave the micromiter down the side of the arm chair and use the 1" spindle as a plug gauge and a cutter as a ring gauge, if you can't turn to a slop free push fit the practice will do you good. Yes cylindrical ground would be nice but just good turning will do.

Did anyone notice in the workshop progress thread that I made an adaptor to take 22mm ID gear cutters on my 1" arbor, just careful turning using the two parts as gauges no measureing instruments, did the job and I did not notice the tell tale sound of an eccentric cut and that needed reversing to machine either side so a simple "Ring" should be even easier.

Edited By JasonB on 30/01/2017 07:48:50

Did anyone notice in the workshop progress thread that I made an adaptor to take 22mm ID gear cutters on my 1" arbor, just careful turning using the two parts as gauges

That's an interesting one, JB. I'll go look for it. Can you indicate any timing of your posting? Surely only needing one part as the gauge? And the 1" arbor presumably was 1" no more, or was it an unsupported arbor? A good example of principle but not quite as in this case where we don't actually know how wide these cutters might be. After all, the advantage of the horizontal, for turning off large amounts of stock, is the supported arbor? I'm learning, so keen to know what others do with their horizontal millers.

OP,

Our little Centecs run a 1"arbor with MT2, so I would think 1 1/4" would not be outlandish. Problem I see is that of providing keying for wide cutters, unless the diameter difference is sufficient. What are your current arbor diameters? Making an

arbor might be a better option?