tom senior m1 arbour

Hi chaps.can anyone who owns a tom senior please let me if the arbour should have a keyway in it.i cant work out what holds the cutting wheel in place.my arbour does not have a keyway, and I was told that pressure on the side of the cutter face keeps it in place.this cant be right can it . Michael

Hello Terry

I have a tom senior, and two different size horizontal arbours for it , 3/4" and 1". Both have keyways running along their entire lengths, 1/4" off the top of my head. No way would the pressure of the nut hold a horizontal milling cutter in place while cutting , even with light cuts.

Edited By ronan walsh on 24/09/2013 01:00:39

Hi Terry, Ronan,

Not wishing to contradict but my Tom Senior M1 has a 1" horizontal arbour without a keyway and I have no trouble clamping horizontal milling cutters sufficiently just using the nut, which, does not have to be more than just nipped up to drive the cutter. Admittedly I mostly use fairly thin section cutters i.e. slitting saws etc and this has the advantage of letting the slitting saw slip (tongue twister) rather than breaking the saw blade.

Alan

Alan,

I fully agree, I've used large horizontal mills for years without using the keyway, used large cutters with no problem at all, the keyway would possibly be an advantage in some cases but not 100% necessary, however, I would use the keyway for very heavy cuts.

I've got 2 Tom senior M1's , I've used the horizontal arbor a few times but have never needed to use the keyway.

Richard.

Surely, sawing stainless steel stock several slightly slack slitting saws should sometimes slip safely, substantially saving some shattered saws - circumstances suggest skimming surface slows slicing.

I spent many years on toolroom machines of all sorts.With this sort of work a key is unnecessary and model making is similar. Only on production work where a mill is driven to it's limits of strain is a key essential. Under those conditions the hardened arbour nut can explode with the winding up strain, especially with a gang of large cutters, if no key is fitted. We used to have a guard over the arbor nut anyway. Colin

Now that is as fine an example of alliteration as you will ever get in the model world. Surely superflous to suggest otherwise,Top marks Stub

Unfortunately this seems to be common practice in industry which is why my arbors have a massive amount of scoring.

What Bazyle says is quite right and some cutters are not chamfered at the ends of their bore which exacerbates the problem if they slip; however many horizontal mill arbours don't have a keyway.The main problem here is that if the cutter does slip due to excessive overload it can tighten the nut and make it very difficutt to undo,largely because some arbours that are driven by taper friction have no spanner flats at the taper end to grip it tightly enough to make good use of a long spanner at the nut end.

If you have a keyway some of the spacers need a keyway too to enable their use on thin cutters. Colin