Harrison 140 headstock taper

Can anybody tell me what taper is used in the headstock of a Harrison 140? The handbook says 3 morse but it obviously is not. Thanks.

Hi Nick

I may well be wrong about this but I think that Harrisons usually have a "bush" in the business end of the spindle and the 3MT taper is actually in that bush. Colchester do the same trick. On Colchesters the actual spindle taper is NOT a Morse taper but seems to be one of their own.

Your best bet is to measure the end of the spindle with a DTI and see what the taper actually is.

I've got the same issues with an old IXL Leader that I just acquired, it's headstock is a Colchester Master clone and I'm missing the spindle nose bush. The upside is that when i get round to machining one it can have whatever fitting I like inside!

Keith

Edited By Keith Long on 20/09/2012 15:42:31

Just been looking up your lathe, if the bore is 1 3/8", and the bore at the spindle nose is 1 5/8", you will find its called a 4.5 morse taper. Its a modified standard MT, not sure if its MT 4, or MT 5, proberbly the thick end of MT 4.

My Taiwanese lathe has a 5 MT spindle, with a 3 MT bush, I'd hate to have to pay for MT 5 tooling! Ian S C

Many thanks for your prompt replies. Looking at the handbook again it does look as though there is a bush in the headstock. Looks like another project for the future!

My Harrison M250 (D13 camlock spindle nose, 35mm through bore) has a reducer bush to allow a centre to be fitted.
Every reference I've seen, claims that this bush is a 5MT to 3MT, but I think it might actually be a 4.5MT to 3MT as the dimensions don't seem to marry up for a 5MT.

Your situation may be similar.

Martin.

Same here with my boxford. 4.5 MT to 3MT bush in the headstock. Still availabe new from boxford.

Harrison M300 is MT5, tailstock is MT3