Bridgeport head question
 

Hi All,

I'm a long term lurker but first time poster and I have a question about
Bridgeport heads that I'm hoping someone might be able to help with.

In my home shop I have a Korean stepped pulley Bridgeport clone that was
made in the mid 80's and looks identical to an original Series I
Bridgeport. It's a great machine that was reconditioned a couple of
years ago, and so close in appearance to an original Bridgeport does it
appear to be that original Bridgeport parts were used to refurbish the
head without any problems.

A couple of months ago a friend gave me a variable speed Series II head
that came out of a large production factory where he works. It was
apparently an accessory for a large Bridgeport horizontal mill that was
being scrapped, and as far as I'm aware this variable speed head has
done very little over the years other than sitting around getting
incredibly dirty.

I'd like to replace the old stepped pulley head on my machine with the
Series II head, but the problem for me is the spindles. The Series II
head has a standard R8 taper while my clone has an ISO 30 taper and
changing to the Series II head will obviously mean none of my current
tooling will be suitable.

Of course, I could just bolt the Series II head on and buy some new
tooling, but I've collected quite a bit of ISO 30 stuff over the years
and replacing it all would be costly. I also wish to avoid adapters as
they can make life complicated.

What I was wondering is how interchangeable are the top and bottom
halves of Series I & II Bridgeport heads?

What I was thinking is that if I could transplant the variable speed top
half of the Series II head onto the bottom half of the old stepped
pulley head I'd kill a couple of birds with one stone in that I'd retain
the use of all my tooling and benefit from the new bearings that were
fitted to the old head not long ago and that have not done much since.

I appreciate that the old machine isn't a genuine Bridgeport and there
may be problems associated with that, but what I was hoping to find out
was that assuming for a moment that the old head was identical to a
Bridgeport stepped pulley head would such a swap be possible?

Any help would be greatly appreciated,

--
Regards,
Darren.

Bridgeport head question
 

You can sell your ISO 30 tooling and buy R8 tooling, you should come
about even without messing around ravaging those heads.

i

On 2012-03-26, Noddy wrote:
Hi All,

I'm a long term lurker but first time poster and I have a question about
Bridgeport heads that I'm hoping someone might be able to help with.

In my home shop I have a Korean stepped pulley Bridgeport clone that was
made in the mid 80's and looks identical to an original Series I
Bridgeport. It's a great machine that was reconditioned a couple of
years ago, and so close in appearance to an original Bridgeport does it
appear to be that original Bridgeport parts were used to refurbish the
head without any problems.

A couple of months ago a friend gave me a variable speed Series II head
that came out of a large production factory where he works. It was
apparently an accessory for a large Bridgeport horizontal mill that was
being scrapped, and as far as I'm aware this variable speed head has
done very little over the years other than sitting around getting
incredibly dirty.

I'd like to replace the old stepped pulley head on my machine with the
Series II head, but the problem for me is the spindles. The Series II
head has a standard R8 taper while my clone has an ISO 30 taper and
changing to the Series II head will obviously mean none of my current
tooling will be suitable.

Of course, I could just bolt the Series II head on and buy some new
tooling, but I've collected quite a bit of ISO 30 stuff over the years
and replacing it all would be costly. I also wish to avoid adapters as
they can make life complicated.

What I was wondering is how interchangeable are the top and bottom
halves of Series I & II Bridgeport heads?

What I was thinking is that if I could transplant the variable speed top
half of the Series II head onto the bottom half of the old stepped
pulley head I'd kill a couple of birds with one stone in that I'd retain
the use of all my tooling and benefit from the new bearings that were
fitted to the old head not long ago and that have not done much since.

I appreciate that the old machine isn't a genuine Bridgeport and there
may be problems associated with that, but what I was hoping to find out
was that assuming for a moment that the old head was identical to a
Bridgeport stepped pulley head would such a swap be possible?

Any help would be greatly appreciated,

Bridgeport head question
 

On 26/03/2012 10:13 PM, Ignoramus19246 wrote:

You can sell your ISO 30 tooling and buy R8 tooling, you should come
about even without messing around ravaging those heads.

Hi,

I did think of that, but down here in Australia R8 tooling is not all
that common and it's a 4-6 week wait with horrendous postage charges
from the US. We fare better buying from Asia, but it's still not very handy.

--
Regards,
Noddy.

Bridgeport head question
 

On Mon, 26 Mar 2012 21:39:52 +1100, Noddy wrote:

Hi All,

I'm a long term lurker but first time poster and I have a question about
Bridgeport heads that I'm hoping someone might be able to help with.

In my home shop I have a Korean stepped pulley Bridgeport clone that was
made in the mid 80's and looks identical to an original Series I
Bridgeport. It's a great machine that was reconditioned a couple of
years ago, and so close in appearance to an original Bridgeport does it
appear to be that original Bridgeport parts were used to refurbish the
head without any problems.

A couple of months ago a friend gave me a variable speed Series II head
that came out of a large production factory where he works. It was
apparently an accessory for a large Bridgeport horizontal mill that was
being scrapped, and as far as I'm aware this variable speed head has
done very little over the years other than sitting around getting
incredibly dirty.

I'd like to replace the old stepped pulley head on my machine with the
Series II head, but the problem for me is the spindles. The Series II
head has a standard R8 taper while my clone has an ISO 30 taper and
changing to the Series II head will obviously mean none of my current
tooling will be suitable.

Of course, I could just bolt the Series II head on and buy some new
tooling, but I've collected quite a bit of ISO 30 stuff over the years
and replacing it all would be costly. I also wish to avoid adapters as
they can make life complicated.

What I was wondering is how interchangeable are the top and bottom
halves of Series I & II Bridgeport heads?

What I was thinking is that if I could transplant the variable speed top
half of the Series II head onto the bottom half of the old stepped
pulley head I'd kill a couple of birds with one stone in that I'd retain
the use of all my tooling and benefit from the new bearings that were
fitted to the old head not long ago and that have not done much since.

I appreciate that the old machine isn't a genuine Bridgeport and there
may be problems associated with that, but what I was hoping to find out
was that assuming for a moment that the old head was identical to a
Bridgeport stepped pulley head would such a swap be possible?

Any help would be greatly appreciated,
As I recall the spindles are interchangeable. Maybe not always the
quill though. The quills, I have been told, were individually fit
into the heads. I don't know how true this is. But if your machine is
an exact copy of a Bridgeport then measure the O.D. of the quill and
see if it's the same as the Bridgeport quill. If they are the same
then using this link:
http://home.comcast.net/~tom.jelly/j...%20rebuild.htm
you should be able to swap quills pretty easily. If the quills do
differ substantially then swapping spindles will probably work.
Eric

Bridgeport head question
 

Have you considered swapping the entire head?
If the bolt hole pattern is the same you're part way there. You'd need
to pull your head to verify the mating dimensions. Likely the biggest
issue would be the worm wheel for side to side adjustment assuming the
series II has one.

Personally I'd suggest selling the head if that won't offend your
friend, and buy an inverter. Right now you mostly have to worry about
wearing out belts and bearings. If you think R8 tooling is scarce and
expensive, wait until you need parts for that head...


Jon

Bridgeport head question
 

Noddy wrote:



What I was wondering is how interchangeable are the top and bottom
halves of Series I & II Bridgeport heads?
Nope, won't work. The spindles are different. Due to the height
of the varispeed drive, the 2J spindle is longer, the splined part
sticks up higher to where the driving spline is. Then, the rest of the
spindle is a lot longer, so the longer drawbar is at the top of the head.
I'm not sure how many other critical differences there are, but this
is the big one.

Oh, this is not a series-I vs. series-II difference, this is 1J vs
2J. Most series-II machines have 3 or 4 Hp motors and are completely
scaled up from the 1J and 2J heads. Series-II heads (3J and 4J)
typically have NMTB 40 taper, never R-8.

Jon

Bridgeport head question
 

On Mon, 26 Mar 2012 15:19:10 -0500, Jon Elson
wrote:

Noddy wrote:



What I was wondering is how interchangeable are the top and bottom
halves of Series I & II Bridgeport heads?
Nope, won't work. The spindles are different. Due to the height
of the varispeed drive, the 2J spindle is longer, the splined part
sticks up higher to where the driving spline is. Then, the rest of the
spindle is a lot longer, so the longer drawbar is at the top of the head.
I'm not sure how many other critical differences there are, but this
is the big one.

The spindles are the same -- the difference is made up by a longer hex
on the drawbar. The length below the hex is the same for both the 1J
and 2J.

--
Ned Simmons

Bridgeport head question
 

On Mon, 26 Mar 2012 21:39:52 +1100, Noddy wrote:

Hi All,

I'm a long term lurker but first time poster and I have a question about
Bridgeport heads that I'm hoping someone might be able to help with.

In my home shop I have a Korean stepped pulley Bridgeport clone that was
made in the mid 80's and looks identical to an original Series I
Bridgeport. It's a great machine that was reconditioned a couple of
years ago, and so close in appearance to an original Bridgeport does it
appear to be that original Bridgeport parts were used to refurbish the
head without any problems.

A couple of months ago a friend gave me a variable speed Series II head
that came out of a large production factory where he works. It was
apparently an accessory for a large Bridgeport horizontal mill that was
being scrapped, and as far as I'm aware this variable speed head has
done very little over the years other than sitting around getting
incredibly dirty.

I'd like to replace the old stepped pulley head on my machine with the
Series II head, but the problem for me is the spindles. The Series II
head has a standard R8 taper while my clone has an ISO 30 taper and
changing to the Series II head will obviously mean none of my current
tooling will be suitable.

Of course, I could just bolt the Series II head on and buy some new
tooling, but I've collected quite a bit of ISO 30 stuff over the years
and replacing it all would be costly. I also wish to avoid adapters as
they can make life complicated.

What I was wondering is how interchangeable are the top and bottom
halves of Series I & II Bridgeport heads?

What I was thinking is that if I could transplant the variable speed top
half of the Series II head onto the bottom half of the old stepped
pulley head I'd kill a couple of birds with one stone in that I'd retain
the use of all my tooling and benefit from the new bearings that were
fitted to the old head not long ago and that have not done much since.

I appreciate that the old machine isn't a genuine Bridgeport and there
may be problems associated with that, but what I was hoping to find out
was that assuming for a moment that the old head was identical to a
Bridgeport stepped pulley head would such a swap be possible?

Any help would be greatly appreciated,

Listen to Gunner and Jon. get a VFD for your mill and have your
variable speed and taper 30. You won't like R8 after having Taper 30.
You're just asking for trouble trying to make one out of two.

Karl

Bridgeport head question
 

On 27/03/2012 1:55 AM, wrote:

As I recall the spindles are interchangeable. Maybe not always the
quill though. The quills, I have been told, were individually fit
into the heads. I don't know how true this is. But if your machine is
an exact copy of a Bridgeport then measure the O.D. of the quill and
see if it's the same as the Bridgeport quill. If they are the same
then using this link:
http://home.comcast.net/~tom.jelly/j...%20rebuild.htm
you should be able to swap quills pretty easily. If the quills do
differ substantially then swapping spindles will probably work.
Eric

Excellent. Many Thanks Eric, I'll give that a try.

--
Regards,
Noddy.

Bridgeport head question
 

On 27/03/2012 7:19 AM, Jon Elson wrote:

Nope, won't work. The spindles are different. Due to the height
of the varispeed drive, the 2J spindle is longer, the splined part
sticks up higher to where the driving spline is. Then, the rest of the
spindle is a lot longer, so the longer drawbar is at the top of the head.
I'm not sure how many other critical differences there are, but this
is the big one.

Bugger.

Oh, this is not a series-I vs. series-II difference, this is 1J vs
2J. Most series-II machines have 3 or 4 Hp motors and are completely
scaled up from the 1J and 2J heads. Series-II heads (3J and 4J)
typically have NMTB 40 taper, never R-8.

Thanks Jon. In my original ramblings I had my terminologies mixed up.
The vary speed head is in fact a 2J head, and my original is a J head
(or, at least, a very close copy of a J head).


--
Regards,
Noddy.

Bridgeport head question
 

On 27/03/2012 4:51 AM, Jon Anderson wrote:

Have you considered swapping the entire head?
If the bolt hole pattern is the same you're part way there. You'd need
to pull your head to verify the mating dimensions. Likely the biggest
issue would be the worm wheel for side to side adjustment assuming the
series II has one.

HI Jon. I'm going to try a straight swap today, as the lower halves of
the two heads look identical.

Personally I'd suggest selling the head if that won't offend your
friend, and buy an inverter. Right now you mostly have to worry about
wearing out belts and bearings. If you think R8 tooling is scarce and
expensive, wait until you need parts for that head...

That's also something to consider, thanks.

I've been more than happy with the machine's original J head, and the
only reason I'm playing around with this now is because it's (so far at
least) a zero cost option. Ideally, if I could somehow get the machine
swapped from a stepped pulley to variable speed drive without spending a
lot of money I'd be happy.


--
Regards,
Noddy.

Bridgeport head question
 

On 27/03/2012 8:35 AM, Karl Townsend wrote:

Listen to Gunner and Jon. get a VFD for your mill and have your
variable speed and taper 30. You won't like R8 after having Taper 30.
You're just asking for trouble trying to make one out of two.

Thanks Karl, I'm exploring that avenue as we speak.

It may be a smarter option for me to sell off the 2J head and use the
proceeds from that to fund a VFD fitout on the original head.



--
Regards,
Noddy.

Bridgeport head question
 

"Noddy" wrote in message
...
...Ideally, if I could somehow get the machine swapped from a
stepped pulley to variable speed drive without spending a lot of
money I'd be happy.
Regards,
Noddy.

Is there some simple way to mount the second head on the back end of
the ram?

jsw

Bridgeport head question
 

On 27/03/2012 10:06 AM, Jim Wilkins wrote:

Is there some simple way to mount the second head on the back end of
the ram?

I suppose I could, but I don't imagine it would be simple. I already
have a slotting head on the back anyway, and as I have no R8 tooling
mounting the head as it is wouldn't benefit me much.


--
Regards,
Noddy.

Bridgeport head question
 

On 27/03/2012 11:53 AM, Jon Anderson wrote:

Well... my shop CNC for some years was an older Millport converted. It's
a step pulley head, and I ran it with a VFD. I'm converting it back to
manual. Moving down under soon, and pondered which to keep, my J2 BP or
the Millport. I've put enough miles on the BP to replace the VS sheave
bushings twice. The Millport with VFD gives me a wider range of speeds,
and is quieter. All it needs is belts and bearings to freshen the head,
which I can source fairly readily. J2 VS parts, I'd probably have to
have shipped from the States.

You should be able to just do a straight up swap on the two heads. I
thought you had a Series II head, which is something of a monster by
comparison. But given you have a lot of QC tooling, sell the VS head,
buy a VFD, and you'll probably still have some money left over.

My apologies, but my Bridgeport terminology wasn't correct in my
original post. I've since discovered that the vary speed head is in fact
a series I 2J, and my original is a copy of the J head.

BTW, are you down under? I was corresponding with a Noddy in AU some
time back, but emails started bouncing and I lost contact.

Oh boy, what a small world :)

Jon, I am indeed that Noddy, and I'm sorry for losing contact with you.
We did a "tree change" about 18 months ago and moved from suburbia to a
couple of acres in a semi rural area about 50km West of Melbourne, and
in doing so I had to change internet service providers. Somehow in the
move I also managed to loose a lot of my contacts, and I'm still trying
to get them all back.

I'll send you my current email address if you're interested, as I'd be
delighted to continue where we left off.

--
Regards,
Noddy.

Bridgeport head question
 

On 3/26/2012 2:01 PM, Noddy wrote:

I've been more than happy with the machine's original J head, and the
only reason I'm playing around with this now is because it's (so far at
least) a zero cost option. Ideally, if I could somehow get the machine
swapped from a stepped pulley to variable speed drive without spending a
lot of money I'd be happy.

Well... my shop CNC for some years was an older Millport converted. It's
a step pulley head, and I ran it with a VFD. I'm converting it back to
manual. Moving down under soon, and pondered which to keep, my J2 BP or
the Millport. I've put enough miles on the BP to replace the VS sheave
bushings twice. The Millport with VFD gives me a wider range of speeds,
and is quieter. All it needs is belts and bearings to freshen the head,
which I can source fairly readily. J2 VS parts, I'd probably have to
have shipped from the States.

You should be able to just do a straight up swap on the two heads. I
thought you had a Series II head, which is something of a monster by
comparison. But given you have a lot of QC tooling, sell the VS head,
buy a VFD, and you'll probably still have some money left over.

BTW, are you down under? I was corresponding with a Noddy in AU some
time back, but emails started bouncing and I lost contact.


Jon

Bridgeport head question
 

On 27/03/2012 1:20 PM, Jon Anderson wrote:

Please do!

Done. If it doesn't go through okay then please let me know as I
sometimes have trouble with my emails.

Since my last email, I've scaled back my plans. Not going to
try and open a commercial shop there. It's just going to be for my
hobby, and maybe a little side work for the vintage car/machinery crowd.

Sounds cool, but just stay out of my town as that's where I'm heading
and I don't want any competition :)

Still hoping to make it there by the end of this year, but looking like
it's going to be early next year.

Next year would probably be better as our dollar will probably drop down
by then and your conversion won't take a hit.

Sadly the cost of living down here has been getting out of control
lately. Melbourne may have been recently voted the world's most liveable
city, but it's rapidly becoming the world's most expensive and I've been
giving serious thought to moving to New Zealand.

--
Regards,
Noddy.

Bridgeport head question
 

On 3/26/2012 4:18 PM, Noddy wrote:

I'll send you my current email address if you're interested, as I'd be
delighted to continue where we left off.

Please do! Since my last email, I've scaled back my plans. Not going to
try and open a commercial shop there. It's just going to be for my
hobby, and maybe a little side work for the vintage car/machinery crowd.
Still hoping to make it there by the end of this year, but looking like
it's going to be early next year.


Jon

Bridgeport head question
 

On Mon, 26 Mar 2012 16:35:45 -0500, Karl Townsend
wrote:

On Mon, 26 Mar 2012 21:39:52 +1100, Noddy wrote:

Hi All,

I'm a long term lurker but first time poster and I have a question about
Bridgeport heads that I'm hoping someone might be able to help with.

In my home shop I have a Korean stepped pulley Bridgeport clone that was
made in the mid 80's and looks identical to an original Series I
Bridgeport. It's a great machine that was reconditioned a couple of
years ago, and so close in appearance to an original Bridgeport does it
appear to be that original Bridgeport parts were used to refurbish the
head without any problems.

A couple of months ago a friend gave me a variable speed Series II head
that came out of a large production factory where he works. It was
apparently an accessory for a large Bridgeport horizontal mill that was
being scrapped, and as far as I'm aware this variable speed head has
done very little over the years other than sitting around getting
incredibly dirty.

I'd like to replace the old stepped pulley head on my machine with the
Series II head, but the problem for me is the spindles. The Series II
head has a standard R8 taper while my clone has an ISO 30 taper and
changing to the Series II head will obviously mean none of my current
tooling will be suitable.

Of course, I could just bolt the Series II head on and buy some new
tooling, but I've collected quite a bit of ISO 30 stuff over the years
and replacing it all would be costly. I also wish to avoid adapters as
they can make life complicated.

What I was wondering is how interchangeable are the top and bottom
halves of Series I & II Bridgeport heads?

What I was thinking is that if I could transplant the variable speed top
half of the Series II head onto the bottom half of the old stepped
pulley head I'd kill a couple of birds with one stone in that I'd retain
the use of all my tooling and benefit from the new bearings that were
fitted to the old head not long ago and that have not done much since.

I appreciate that the old machine isn't a genuine Bridgeport and there
may be problems associated with that, but what I was hoping to find out
was that assuming for a moment that the old head was identical to a
Bridgeport stepped pulley head would such a swap be possible?

Any help would be greatly appreciated,

Listen to Gunner and Jon. get a VFD for your mill and have your
variable speed and taper 30. You won't like R8 after having Taper 30.
You're just asking for trouble trying to make one out of two.

Karl

Ayup.

Gunner

--
Maxim 12: A soft answer turneth away wrath.
Once wrath is looking the other way, shoot it in the head.

Bridgeport head question
 

Ned Simmons wrote:

On Mon, 26 Mar 2012 15:19:10 -0500, Jon Elson
wrote:

Noddy wrote:



What I was wondering is how interchangeable are the top and bottom
halves of Series I & II Bridgeport heads?
Nope, won't work. The spindles are different. Due to the height
of the varispeed drive, the 2J spindle is longer, the splined part
sticks up higher to where the driving spline is. Then, the rest of the
spindle is a lot longer, so the longer drawbar is at the top of the head.
I'm not sure how many other critical differences there are, but this
is the big one.

The spindles are the same -- the difference is made up by a longer hex
on the drawbar. The length below the hex is the same for both the 1J
and 2J.

Wow, sorry to give out bad info, I think Ned is right!

Jon

Bridgeport head question
 

On 2012-03-26, Noddy wrote:
On 27/03/2012 4:51 AM, Jon Anderson wrote:

Have you considered swapping the entire head?
If the bolt hole pattern is the same you're part way there. You'd need
to pull your head to verify the mating dimensions. Likely the biggest
issue would be the worm wheel for side to side adjustment assuming the
series II has one.

HI Jon. I'm going to try a straight swap today, as the lower halves of
the two heads look identical.

Personally I'd suggest selling the head if that won't offend your
friend, and buy an inverter. Right now you mostly have to worry about
wearing out belts and bearings. If you think R8 tooling is scarce and
expensive, wait until you need parts for that head...

That's also something to consider, thanks.

I've been more than happy with the machine's original J head, and the
only reason I'm playing around with this now is because it's (so far at
least) a zero cost option. Ideally, if I could somehow get the machine
swapped from a stepped pulley to variable speed drive without spending a
lot of money I'd be happy.

One thing to check before you do this is the condition of the
parts of the variable speed pulleys to make sure that they don't need
replacement and thus will quickly lead to problems. The things to check
a

1) The Delrin sleeve inside the sliding pulley half, so it will
slide properly on the motor spindle (and on the quill spindle as
well).

2) The key which slides in a slot in the motor's spindle, and
a similar one in the quill's spindle. This is steel with a
skin of Delrin so it slides smoothly in the keyways. it bolts
into the moving half of the pulley, IIRC.

If the latter is worn out (worn to the steel) it will start
wearing the keyway so it will not allow things to slide smoothly
while varying the speed. And this one will require replacing
the spindle of the motor -- or the rotor with the spindle.
(I've had to do this with an old machine.)

Good Luck,
DoN.

--
Remove oil spill source from e-mail
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

Bridgeport head question
 

On 2012-03-27, Jon Anderson wrote:
On 3/26/2012 2:01 PM, Noddy wrote:

I've been more than happy with the machine's original J head, and the
only reason I'm playing around with this now is because it's (so far at
least) a zero cost option. Ideally, if I could somehow get the machine
swapped from a stepped pulley to variable speed drive without spending a
lot of money I'd be happy.

Well... my shop CNC for some years was an older Millport converted. It's
a step pulley head, and I ran it with a VFD. I'm converting it back to
manual. Moving down under soon, and pondered which to keep, my J2 BP or
the Millport. I've put enough miles on the BP to replace the VS sheave
bushings twice. The Millport with VFD gives me a wider range of speeds,
and is quieter. All it needs is belts and bearings to freshen the head,
which I can source fairly readily. J2 VS parts, I'd probably have to
have shipped from the States.

You should be able to just do a straight up swap on the two heads. I
thought you had a Series II head, which is something of a monster by
comparison. But given you have a lot of QC tooling, sell the VS head,
buy a VFD, and you'll probably still have some money left over.

Another reason for keeping the step pulley and using a VFD is
that your power bill will go down significantly. When Bridgeport went
from the manual to the variable speed in the J series heads, they had to
increase the horsepower to make up for that lost to friction in the
belts of the vari-speed pulley.

Good Luck,
DoN.

--
Remove oil spill source from e-mail
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

Bridgeport head question
 

On 29/03/2012 11:25 AM, DoN. Nichols wrote:

One thing to check before you do this is the condition of the
parts of the variable speed pulleys to make sure that they don't need
replacement and thus will quickly lead to problems. The things to check
a

1) The Delrin sleeve inside the sliding pulley half, so it will
slide properly on the motor spindle (and on the quill spindle as
well).

2) The key which slides in a slot in the motor's spindle, and
a similar one in the quill's spindle. This is steel with a
skin of Delrin so it slides smoothly in the keyways. it bolts
into the moving half of the pulley, IIRC.

If the latter is worn out (worn to the steel) it will start
wearing the keyway so it will not allow things to slide smoothly
while varying the speed. And this one will require replacing
the spindle of the motor -- or the rotor with the spindle.
(I've had to do this with an old machine.)

Good Luck,
DoN.

Thanks for that DoN.

I did a quick tear down of the vary speed head on Tuesday and
unfortunately it's in sad shape. My friend was told that it had done
little or no work, but it's quite obviously been worked to death with
very little maintenance and it needs to be fully rebuilt. Given that the
only reason for trying this swap was that it was hopefully going to be a
no (or very low) cost option I've now ruled out ever using the vary
speed head and will try to sell it and put the funds towards a VFD
conversion at some future point.

Oh well. Nothing ventured and all that hoo hah.....

Thanks to everyone for their help. It's been greatly appreciated.



--
Regards,
Noddy.