30 int horizontal arbours

I have a few horizontal arbours for my tom senior milling machine. Horizontal milling is an outdated process in many ways, but as the cutters are available cheaply on ebay etc, its still useful to me. I picked up some larger cutters with a 1 1/4" bore size. Haven't come across a 30 int 1 1/4" horizontal arbour though. Is 1 1/4" oversize for the 30int taper ?

It should be possible to make some bore reducers for the cutters, methinks.

MichaelG.

Horizontal milling may be outdated in industry, where making thousands of parts at rock bottom prices matters, but in the model and home machine shop, they are as good as they ever were, and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 agree Phil, i have used my horizontal to slog off large amounts of metal before switching to the more nimble vertical. I will look at rotagrip and gloster for arbours.

.

I've never made one, so I can't be sure ... but I would think that the process would be first to bore [and maybe lap, or hone] the internal diameter in some oversize stock ... then mount this on a between-centres arbor and skim the outside diameter to size [again maybe lapping or honing].

MichaelG.

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

Even if the bore of the collars were a smidge oversize to the mandrel diameter as long as the ends of the collars were square to their bore why would a cutter not run true ?

Mick

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

If the bore and the OD are machined at the same setting why would it not run true ?

We have many on here who post they can turn over 20" to a taper of less than 0.01mm and now we have other querying what should be a very simple operation.

Come on lads you can't have it both ways.

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

John, not sure if you are saying my comment is daft, or u r having a dig, perhaps I misread it

Mick

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?

Yes, like the collet chuck idea, been suggested to me before! and you can get stub arbors for H mill cutters from the same sourcesI also some time ago opened a box of goodies passed to me by an ex engineer (who now does woodwork EUGH!) and found a nice selection of R8 milling arbors in imperial sizes, and then found that ARC do a int30 to R8 adapter, so thats another few added to the arsenal. Heres one for John Stevenson, which I have long since stopped worrying about. Almost all my setups on the H mill, rather than producing a smooth even rotary cutter sound, tend to go grunt grunt grunt when I am really moving some metal, and yet the finish is good, and the cutter wear seems to be even, with no detectable bend in the arbor, but some scoring, and therefore possibly a bit of wear, and indeed possibly some eccentric cutter resharpening adding to the grunting. It still works for me, I would love it to "sound right" but I have learned to live with it.

Phil