Changing Tapers on an Arrand boring head.

Right, I now have my Arrand Boring head with a 3 MT Taper. I also have the Arrand 2MT Taper.

However I am blowed if I can undo the 3MT Taper from the head. There must be a simple way of doing this, but the mind is blank.

Andrew.

I believe these are just screwed in with a RH thread. So, essentially, grip the shank and give the head a sharp tap in the appropriate direction.

I have done this successfully but don't remember the precise method. The shank could be gripped in the machine's own taper and the tap delivered via a suitably-gripped boring tool. The basic idea is to use the inertia of the shank against some shock loading to the head.

I would guess that a boring head shank would be easier to remove than the same make of flycutter shank because of the intermittent action of the latter.

Edited By ega on 18/06/2019 22:02:57

When all else fails the shank could be cut off and drilled out, I would regard the shank as expendable if it cannot be removed without risking damage to the boring head.

Mike

Looks as though I may have to cut it off and drill it out. I have tried shock loading the head with the taper fixed and I am afraid I am going to do some damage if I hit the large spanner any harder!

Thanks ,

Andrew.

PS It is possible to phone Arrand and talk to the proprietor's son though I don't know how far he could help. Posting this in the hope of anticipating your attack on the taper and will add the number if I can find it by searching the site.

PPS See penultimate post here:

https://www.model-engineer.co.uk/forums/postings.asp?th=94955

Edited By ega on 18/06/2019 22:09:53

Andrew,

They do unscrew, the thread is right hand. Try some heat on the head and a soak of the joint with WD 40 before you try the impact, it might just shock free then

It seems a shame to have to resort to drilling it out

Good luck.

Brian

Andrew,

I have an old Arrand catalogue dated 2003 in which it states -

"Boring heads have interchangeable shanks. Threaded interchangeable shanks are available (see chart opposite) so boring head can be used on machines with different tapers , or if you change you machine, a nrew shank can easily fitted to suit."

The "chart opposite) list a wide variety of shanks not just Morse taper ones.

Very unfortunately, Arrand ceased trading some years ago probably because of Far Eastern completion

Eric

Agreed, but I gather they are prepared to sell such remaining items as they have in stock - see my post above for contact.

Edited By ega on 19/06/2019 09:57:36

Does your MT2 arbor have a male 1.5" X 18 thread? That size seems to be a standard for smaller boring heads. Arceurotrade sell replacement arbors with that thread. If so, the MT3 one could be replaced if you have to destroy it.

If there is a flange on the arbor where it screws into the boring head, a couple of flats could be milled in the flange to hold it securely in a vise. Then more torque could be applied to the head.

Thanks everyone,

The shank has now been unscrewed! Perversely, I managed to unscrew it by hand. I think all the shock loading and heating persuaded it to surrender to mere unthreading by hand. I can assure everyone that it was stuck tight before.

Thanks,

Andrew.