Tapers
 

I need a way to use 1/8" dia. straight shank cutters in a Gorton
pantograph engraver with a taper socket spindle. A ready made collet is
very expensive to buy new, so I was considering trying to make one from
drill rod. The problem is that oddball Gorton spindle taper. Is there
any simple, accurate way to set up to turn this without all the trial
and error? Is it even reasonable to attempt to do this without some
sort of precision grinding equipment? I'm not sure what the spindle
speeds are since the data plate with the information is missing and
they couldn't help at Gorton, other than to tell me the machine (a 3-F)
has not been made since the 1950's, but it takes almost a full minute
for it to come up to full speed and so I'm guessing it could be
somewhere around 15,000 rpm or more. Any advice appreciated.
Mike

I've made a few 'matching' tapers, but probably bigger scale
than what you need. A few thoughts follow:

Don't use drill rod if not absolutely necessary, hard to machine and
get a good finish.

The key to success is to be able to put the work piece back into
lathe accurately after making a trial fit.

Try to set up an old collet in such a way that you can use an accurate
indicator to align your compound rest to it's angle.

If possible, create the 1/8 bore first, then use a mandrel or between
centers to work on the taper. When sufficient length of taper is done,
test with Prussian blue to spindle of machine. Adjust compound if
required, and so on.

Good luck,
Ace


"KyMike" wrote in message
oups.com...
I need a way to use 1/8" dia. straight shank cutters in a Gorton
pantograph engraver with a taper socket spindle. A ready made collet is
very expensive to buy new, so I was considering trying to make one from
drill rod. The problem is that oddball Gorton spindle taper. Is there
any simple, accurate way to set up to turn this without all the trial
and error? Is it even reasonable to attempt to do this without some
sort of precision grinding equipment? I'm not sure what the spindle
speeds are since the data plate with the information is missing and
they couldn't help at Gorton, other than to tell me the machine (a 3-F)
has not been made since the 1950's, but it takes almost a full minute
for it to come up to full speed and so I'm guessing it could be
somewhere around 15,000 rpm or more. Any advice appreciated.
Mike

"KyMike" wrote in message
oups.com...
I need a way to use 1/8" dia. straight shank cutters in a Gorton
pantograph engraver with a taper socket spindle. A ready made collet is
very expensive to buy new, so I was considering trying to make one from
drill rod. The problem is that oddball Gorton spindle taper. Is there
any simple, accurate way to set up to turn this without all the trial
and error? Is it even reasonable to attempt to do this without some
sort of precision grinding equipment? I'm not sure what the spindle
speeds are since the data plate with the information is missing and
they couldn't help at Gorton, other than to tell me the machine (a 3-F)
has not been made since the 1950's, but it takes almost a full minute
for it to come up to full speed and so I'm guessing it could be
somewhere around 15,000 rpm or more. Any advice appreciated.
Mike

Making something you can spin at that speed requires a little thought. I'd
be inclined to make an adapter that takes a collet for a Dremel tool. You'd
want to make it of mild steel (not drill rod) or even brass. I've never had
very good luck using the compound. I prefer to offset the tailstock, put
the faceplate on the lathe, mount the work between centers and drive it with
a dog. The nice thing about this approach is that, once you have the
recipie down, you can repeat it by simply starting with pieces of stock that
are the same length. I made an alignment bar that is just about the maximum
lenght the lathe can hold out of 2 in. diameter aluminum with the last
couple inches on each end cut and polished to the same diameter. Then I can
put a dial indicator on the tool post and it makes setting the offset (and
returning the tailstock precisely to center) very easy. You simply
calculate the offset required to give you the taper you want, given the
length of your stock.

Jerry

I may have found a source for a used Gorton taper collet. I had the
idea that drill rod was supposed to give a better finish, but if I have
to go ahead and make an adapter I will use mild steel instead. Thanks
for the help everyone.
Mike

On 8 Jul 2005 14:51:56 -0700, "KyMike" wrote:

I need a way to use 1/8" dia. straight shank cutters in a Gorton
pantograph engraver with a taper socket spindle. A ready made collet is
very expensive to buy new, so I was considering trying to make one from
drill rod. The problem is that oddball Gorton spindle taper. Is there
any simple, accurate way to set up to turn this without all the trial
and error? Is it even reasonable to attempt to do this without some
sort of precision grinding equipment? I'm not sure what the spindle
speeds are since the data plate with the information is missing and
they couldn't help at Gorton, other than to tell me the machine (a 3-F)
has not been made since the 1950's, but it takes almost a full minute
for it to come up to full speed and so I'm guessing it could be
somewhere around 15,000 rpm or more. Any advice appreciated.
Mike


Gorton collets come up on Ebay with some regularlty, and cheaply
enough. Id not try making one personally for my 3-Z because of the
complexity.

Mine comes up to full speed in about 10 seconds. Shrug

Gunner

"Considering the events of recent years,
the world has a long way to go to regain
its credibility and reputation with the US."
unknown

On Sat, 09 Jul 2005 00:47:30 +0000, Jerry Foster wrote:

I made an alignment bar that is just about the maximum
lenght the lathe can hold out of 2 in. diameter aluminum with the last
couple inches on each end cut and polished to the same diameter. Then I can
put a dial indicator on the tool post and it makes setting the offset (and
returning the tailstock precisely to center) very easy. You simply
calculate the offset required to give you the taper you want, given the
length of your stock.


Robert "teenut" Bastow once described a similar method of realigning
one's tailstock using a much smaller device.

Here's a copy of his description:
http://yarchive.net/metal/tailstock_realignment.html

In another article he credited Tubal Cain for the method, but it is a
cheap and elegant way of doing it and I'm glad he mentioned it.