Drummond M Spindle bored out !?

[zx9]

My Drummond should have a 1MT taper in the spindle but some kind sole has bored it to exactly 3/4 of an inch. It is parallel and approximately two inch deep, there is a further ridge where the diameter decreases untill about 1/4" where it closes up to the original bore.
I guess I have two questions:

Why would anyone open the spindle up to 3/4 of an inch? I believe that it has been done with care as the bore is very cleanly turned, almost polished, it can not be accidental miss use of a boring bar.

And two what should I do about it, ignore it is not really an option because I wanted to be able to turn between centres.
Should I:
A. Try to find a better spindle - Hen's teeth comes to mind.
B. Make another spindle - possible there are drawings on Yahoo but I can not turn between centres remember. I could use the four jaw so it is do-able, if that is the option what steel to use, EN8 or 24?
C. Make a 3/4 x 2" plug to loctite into the old spindle and bore that out to 1MT or 2MT no reason why not go up a taper size. Again what steel to use?
D. Stick a chuck back on it, hide the lathe dogs at the back of a draw and forget there is a problem.

 

[Maker]

I'd turn a point on a steel bar in a chuck and use that as a centre, take a light skim of the surface every time you use it to make sure it's perfectly aligned.

That's what I do on my Chipmaster, I don't even know if the spindle has an internal taper.

 

[grim_d]

I'd turn a point on a steel bar in a chuck and use that as a centre, take a light skim of the surface every time you use it to make sure it's perfectly aligned.

I don't have the special hen's teeth bush to go in my awkward mt4.5/jarno taper on my Harrison so i just do the above. I have a centre that just gets marginally shorter each time I use it.

 

[zx9]

I'd turn a point on a steel bar in a chuck and use that as a centre, take a light skim of the surface every time you use it to make sure it's perfectly aligned.

That's what I do on my Chipmaster, I don't even know if the spindle has an internal taper.

I had not thought of that, very Keep It Simple Stupid, I like it.

 

[bigegg]

long term, can you make a disk with a point? - that bolts to the faceplate?

or a faceplate that screws to the spindle nose - again with a point?

like this: (plan view)


____________∆___________

 

[eLuSiVeMiTe]

I'd turn a point on a steel bar in a chuck and use that as a centre, take a light skim of the surface every time you use it to make sure it's perfectly aligned.

That's what I do on my Chipmaster, I don't even know if the spindle has an internal taper.

Pretty much what I do.
Can use a spindle collet and my catch plate at the same time though so gives me more room to play with.

 

[bigegg]

long term, can you make a disk with a point? - that bolts to the faceplate?

or a faceplate that screws to the spindle nose - again with a point?

like this: (plan view)


____________∆___________

been thinking about this.

if you make a faceplate with an m10?
thread in the center, you could screw in a bolt, and turn it to a centre.

it would then be replaceable.
you wouldn't need to turn down a huge amount of stock to make the point.

it *should* be re-seatable without having to re-cut.

 

[zx9]

been thinking about this.

if you make a faceplate with an m10?
thread in the center, you could screw in a bolt, and turn it to a centre.

it would then be replaceable.
you wouldn't need to turn down a huge amount of stock to make the point.

it *should* be re-seatable without having to re-cut.

I like both your ideas, thing is the centre would revolve at the same speed as the work so the centre would not need to be hardened unlike the tail stock centre.

 

[bigegg]

or cast(you could turn from a *huge* blank)
a T - shaped piece.
turn the shank to 3/4", and thread into the "head" to match the spindle.

you could then reverse it, put the shaft into the headstock. spin onto the spindle, and bore out go mt1?

you might lose some "between centres" length, depending on how thick the "head"/faceplate has to be to get the mt1

 

[bigegg]

I like both your ideas, thing is the centre would revolve at the same speed as the work so the centre would not need to be hardened unlike the tail stock centre.

doesnt the spindle/centre/faceplate *always* spin at the same speed as the work?

 

[rtbcomp]

^^ Yes, which is why it doesn't need to be hardened because there is no relative movement between centre and workpiece.

 

[bigegg]

^^ Yes, which is why it doesn't need to be hardened because there is no relative movement between centre and workpiece.

im confused...

i never said it had to be hardened?

in my defense, ive been awake for 36hrs, so am easily confuddled.

 

[Wallace]

I only found out recently my Raglan Little John has a Morse taper in the spindle as the spare machine came with a homemade drive plate on a morse taper! Embarrassing really as my Father bought the machine in the 70's! Any time I have needed to turn between centres I machine a centre as suggested above with a shoulder to sit against the chuck.

 

[zx9]

doesnt the spindle/centre/faceplate *always* spin at the same speed as the work?

Yes but not the centre in the tail stock (unless it is a live centre) as I said above.

im confused...

i never said it had to be hardened?

in my defense, ive been awake for 36hrs, so am easily confuddled.

No worries, I've had a bit of a tough day with directors of a museum knocking back on a project we were supposed to start at 8AM this morning, staff and materials all ready on site before the proverbial hit the fan. I've had a day of fire fighting whilst walking around 3 1/2 miles round the site, we managed to agree on part of the works and get hands on tools by 11 but the other room is on hold for a week or so, I am not even supposed to be PM on this one.

 

[Dieselman 63]

I'd turn a point on a steel bar in a chuck and use that as a centre, take a light skim of the surface every time you use it to make sure it's perfectly aligned.

That's what I do on my Chipmaster, I don't even know if the spindle has an internal taper.

If it’s the same as the Bantam, it’s got an MT4 taper in the headstock and MT3 in the tail

 

[Maker]

I had a look in the handbook after my first post and there is a reducing sleeve thing I'm missing. Lathes.co.uk says it's a No.4 taper but the big end of that is only 1.23" and the headstock bore is 1.3" so it can't be.

They say the "Mk 3 Bantam" (Harrison M250 to you and I ) had a 35mm bore and No.5 taper so it could be that. You're right about the tailstock though.

 

[Dieselman 63]

I had a look in the handbook after my first post and there is a reducing sleeve thing I'm missing. Lathes.co.uk says it's a No.4 taper but the big end of that is only 1.23" and the headstock bore is 1.3" so it can't be.

They say the "Mk 3 Bantam" (Harrison M250 to you and I ) had a 35mm bore and No.5 taper so it could be that. You're right about the tailstock though.

That site is good but not always correct. I will look in my original sales brochure when I get home (Sunday).

 

[Dieselman 63]

I had a look in the handbook after my first post and there is a reducing sleeve thing I'm missing. Lathes.co.uk says it's a No.4 taper but the big end of that is only 1.23" and the headstock bore is 1.3" so it can't be.

They say the "Mk 3 Bantam" (Harrison M250 to you and I ) had a 35mm bore and No.5 taper so it could be that. You're right about the tailstock though.

Bantam spindle nose mounting is 4MT, Chippie is 3MT but there is a bush to mount it. This is interesting as the Bantam spindle bore is 25.4mm, and the Chippie is 35mm. You’d think it would be the other way around...

This info is from the 1973 catalogue. Note that Lathes.co.uk shows the Bantam as weighing 343kg but the catalogue shows it as being 445kg for the 20” bed and an extra 30kg for the 30”. The Chipmaster weighs 508kg.

 

[Hood]

You sure what you are reading is not the taper in the bush itself? That is certainly the way the Student was listed, 3MT in spindle bush. I didn't think the taper in the spindle itself was a MT but I never measured so I suppose it may have been.


Edit
Screenshot from Student manual.

 

[Dieselman 63]

You sure what you are reading is not the taper in the bush itself? That is certainly the way the Student was listed, 3MT in spindle bush. I didn't think the taper in the spindle itself was a MT but I never measured so I suppose it may have been.


Edit
Screenshot from Student manual.

View attachment 150600

Taper in the bush for the Chipmaster yes, but the Bantam spindle is tapered to accept 4MT