I have a Harrison M250 lathe and I already have a set of collets for it that
use the spring loaded vanes that squeeze in as you tighten it in its special
chuck. These have the advantage of wide range of diameters for each collet,
but two disadvantages in that you have to have about 50mm length minimum to
grip ( you cant just grip a short shoulder - the rear of the vanes collaps
in ), and by the time you get them in their special chuck you're about 200mm
away from the nose of the spindle. So I want to get a set of 'tube collets'
for work that really needs them.

Apparently, there are 2 types for the Harrison. One uses a drawbar ( which
I'm used to in other lathes ) and the other uses a chuck. I think I'd
prefere the drawbar type, but they seem to sell a lot more of the chuck type
for some reason. If any of you have had experience with tube collets for the
M250 or similar that use a chuck or drawbar I'd love to hear about it. I
cant find any info on Harrison/Colchesters web site so I would appreciate
any tips or warnings you might have before I go and spend the money. They
ain't cheap.


Thanks,
Dean.

"Dean" wrote in message ...

Apparently, there are 2 types for the Harrison. One uses a drawbar ( which
I'm used to in other lathes ) and the other uses a chuck. I think I'd
prefere the drawbar type, but they seem to sell a lot more of the chuck type
for some reason. If any of you have had experience with tube collets for the
M250 or similar that use a chuck or drawbar I'd love to hear about it. I
cant find any info on Harrison/Colchesters web site so I would appreciate
any tips or warnings you might have before I go and spend the money. They
ain't cheap.

I think the answer may depend on your intended use. If you are
planning on production quantities rather than "one-off" work, the
answer may be different.
I love the Hardinge/ Sjogren collet chucks for "one-off" type work,
however I realize that they have limitations when it comes to
production work. For production work, the lever type draw bar setup
can't be beat. Also, the Hardinge/Sjogren type chuck can get difficult
to use when lots of coolant is being used (tightening the wheel gets
difficult.)
I like the ease of switching back and forth between a collet chuck and
a 3 or 4 jaw chuck or faceplate. Changing from a draw bar setup is
more involved, unless you have the collet taper built into the spindle
(like Hardinge).
The type of work I do involves frequent switching back and forth
between a collet setup and a chuck or faceplate. Again, your mileage
may vary depending on the nature of the work you do.

Regards,
Dave Ficken
Meridian Machinery
http://www.mermac.com

(Dave Ficken) wrote in message . com...
"Dean" wrote in message ...

Apparently, there are 2 types for the Harrison. One uses a drawbar ( which
I'm used to in other lathes ) and the other uses a chuck. I think I'd
prefere the drawbar type, but they seem to sell a lot more of the chuck type
for some reason. If any of you have had experience with tube collets for the
M250 or similar that use a chuck or drawbar I'd love to hear about it. I
cant find any info on Harrison/Colchesters web site so I would appreciate
any tips or warnings you might have before I go and spend the money. They
ain't cheap.

I think the answer may depend on your intended use. If you are
planning on production quantities rather than "one-off" work, the
answer may be different.
I love the Hardinge/ Sjogren collet chucks for "one-off" type work,
however I realize that they have limitations when it comes to
production work. For production work, the lever type draw bar setup
can't be beat. Also, the Hardinge/Sjogren type chuck can get difficult
to use when lots of coolant is being used (tightening the wheel gets
difficult.)
I like the ease of switching back and forth between a collet chuck and
a 3 or 4 jaw chuck or faceplate. Changing from a draw bar setup is
more involved, unless you have the collet taper built into the spindle
(like Hardinge).
The type of work I do involves frequent switching back and forth
between a collet setup and a chuck or faceplate. Again, your mileage
may vary depending on the nature of the work you do.

Regards,
Dave Ficken
Meridian Machinery
http://www.mermac.com

Dave's comment about the Hardinge/Sjogren is helpful, thanks, but
there is another angle. I figure most face-mount collet chucks are
bought by people who simply want to use a collet style e.g. 5C that
won't fit in their spindle. Your M250 accommodates a 5C so you
actually do have a choice. I have never used the face-mount style but
what with the overhang it creates more opportunities for inaccuracy.
In general the drawbar and 5C/5MT adapter don't get in the way unless
you need to feed a long piece of 1"+ stock through the spindle.

For production work, the lever type draw bar setup can't be beat. Also, the
Hardinge/Sjogren type chuck can get difficult to use when lots of coolant is
being used (tightening the wheel gets difficult.)


For production, the rear closer is the way to go, which is more-or-less
standard on the HLV-H as the spindle has a 5C taper.

Sjogren transferred manufacturing of his circa 1929 chuck to Hardinge, where it
became the Hardinge-Sjogren.

For the past decade, give or take, the Sjogren chuck has been made by ATS
Workholding, and all support is from them.

The Sjogren is perhaps the best add-on chuck, and with inside/ouside threaded
collets you can do repeat work, using an adjustable stop.