Rescuing a Damaged Head Stock Morse Taper

[SteveW]

Guys,

I had call from a mate of mine with, I think, an old Bantam edit: he tells its a Little John lathe but could be wrong. Its the one with the continuously variable speed lever sticking out forward at the head stock end and a one inch hole down the spout. We had one a school, a brilliant piece of kit but its been a long time.

He had rediscovered his drawer of never used split collets and the head stock adaptor and had a plan to use them. Trying the adaptor in the head stock highlighted some damage down the taper and further examination with blue reveal a worrying history of high and low spots. Certainly running a finger in there showed some damage.

Its likely a very long history of use and I guess too many long bits of rod stuffed as deep as possible in the chuck has left its mark.

So the question: Any suggestion as to what to do to mitigate and maybe rescue the situation?

Also, and based on lessons learnt here, perhaps we should all be a bit careful stuffing long bit of rod too far into the head stock.

[millman]

From your description it sounds like a Chipmaster, same size as a Bantam but with the dreaded Kopp variator for infinitely variable speed as opposed to the Bantam which has a geared headstock. I have a Bantam that is about sixty years old and I had a similar problem, the spindles on Chipmasters and Bantams are identical at the chuck end, and the only real option you have is to run the machine at a couple of hundred revs and stone the taper with a round carborundum stone. I did consider grinding the taper with a toolpost grinder, it would have been quite easy as I have a taper turning attachment fitted but decided not to do it as the insert doesn’t leave much room as it is to get a screwdriver behind it for removal and grinding would make that gap even smaller, plus I am a coward. As I am writing this another possibility springs to mind, reproduce the taper on a bit of aluminium bar and use it as a lap with a bit of valve grinding paste.

[uuu]

I had a damaged MT2 taper on a lathe - a friend lent me a reamer of the right size and that fixed it. OK, I expect grinding would have delivered a better result, but I was happy with the quick fix.

Wilf

[ettingtonliam]

I had a MK2 LittleJohn for quite a few years, a while back, and it was a good machine. The spindle bore was 1 1/32", and I think the taper was 4MT. A taper reamer gently inserted into the taper bore, and rotated by hand will soon knock off the raised areas. There are several 4MT taper reamers on Ebay at the moment (Chinese, obv.) at between £30 and £40, which isn't too bad for quite a big lump of metal. Unfortunately, having used it for around 5 minutes, your friend will probably never need it again!

Any progress on Locomotion?

[Jo]

Got a hand scraper and some blue and a 4MT to use as a master taper?

Jo