I volunteered to fix a bunch of older Vemco drafting machines (elbow type)
for the local high school. A frequent fault is that the graduated base
plate can no longer be clamped by the "Protractor Brake". Said brake is
simply a thin piece of aluminum with a shoulder that pinches (clamps) down
on the protractor. It is approximately the size of a nickel and about as
thick. I successfully filed 0.007 inches of one side, however, it is a
difficult task freehand and removes a lot of skin from the fingertips.
If it weren't aluminum, I would simply place it on my magnetic chuck.

One thought I had was to carve a recess into a block of wood and use that as
a work stop. An advancement would be to drill a hole into said block of
wood and use either my vacuum pump or mighty-vac to hold the part down.
Could also make in impression in a chunk of clay, but SWMBO says it would
take at least 24 hours to fire in her huge kiln.

Other ideas appreciated.

Ivan Vegvary

Ivan Vegvary wrote:

I volunteered to fix a bunch of older Vemco drafting machines (elbow type)
for the local high school. A frequent fault is that the graduated base
plate can no longer be clamped by the "Protractor Brake". Said brake is
simply a thin piece of aluminum with a shoulder that pinches (clamps) down
on the protractor. It is approximately the size of a nickel and about as
thick. I successfully filed 0.007 inches of one side, however, it is a
difficult task freehand and removes a lot of skin from the fingertips.
If it weren't aluminum, I would simply place it on my magnetic chuck.

One thought I had was to carve a recess into a block of wood and use that as
a work stop. An advancement would be to drill a hole into said block of
wood and use either my vacuum pump or mighty-vac to hold the part down.
Could also make in impression in a chunk of clay, but SWMBO says it would
take at least 24 hours to fire in her huge kiln.

Other ideas appreciated.

Ivan Vegvary

See my clamping suggestion from a day or two ago for Bob's cut out
coins.

super glue to steel. surface grind, heat part with propane torch to remove.

Karl

In article ,
"Ivan Vegvary" wrote:

Could also make in impression in a chunk of clay, but SWMBO says it would
take at least 24 hours to fire in her huge kiln.

And after it was fired, the part wouldn't fit - clay shrinks when fired.

Thin (not thick and foamy) double-stick tape might do perfectly well, if
the parts are clean and flat. The superglue already suggested would also
work. If the part is prone to creep during filing despite the tape, a
couple of stops to catch the edge of the plate might be all the help it
needs.

Hot glue is yet another option. Fixturing alloy would be another.

--
Cats, coffee, chocolate...vices to live by

"Ecnerwal" wrote in message
...
In article ,
"Ivan Vegvary" wrote:

Could also make in impression in a chunk of clay, but SWMBO says it would
take at least 24 hours to fire in her huge kiln.

And after it was fired, the part wouldn't fit - clay shrinks when fired.

Thin (not thick and foamy) double-stick tape might do perfectly well, if
the parts are clean and flat. The superglue already suggested would also
work. If the part is prone to creep during filing despite the tape, a
couple of stops to catch the edge of the plate might be all the help it
needs.

Hot glue is yet another option. Fixturing alloy would be another.

I've got a bunch of Indium/Bismuth that would be perfect - it shrinks
..0002"/" after an hour and the eutectic temp. is 136F.
The trouble is that it's $80.00/lb but I might make a send out a half pound
as a courtesy. I think that would be enough and it's reusable.

JC

"Ivan Vegvary" wrote in message
...
I volunteered to fix a bunch of older Vemco drafting machines (elbow type)
for the local high school. A frequent fault is that the graduated base
plate can no longer be clamped by the "Protractor Brake". Said brake is
simply a thin piece of aluminum with a shoulder that pinches (clamps) down
on the protractor. It is approximately the size of a nickel and about as
thick. I successfully filed 0.007 inches of one side, however, it is a
difficult task freehand and removes a lot of skin from the fingertips.
If it weren't aluminum, I would simply place it on my magnetic chuck.

I have engraved pocker chips by milling a socket for them in block of wood,
and then clamping the edges down while I worked on the middle.


One thought I had was to carve a recess into a block of wood and use that
as a work stop. An advancement would be to drill a hole into said block
of wood and use either my vacuum pump or mighty-vac to hold the part down.
Could also make in impression in a chunk of clay, but SWMBO says it would
take at least 24 hours to fire in her huge kiln.

Other ideas appreciated.

Ivan Vegvary

On Mar 12, 2:34*pm, "Ivan Vegvary" wrote:
...Said brake is
simply a thin piece of aluminum with a shoulder that pinches (clamps) down
on the protractor. *It is approximately the size of a nickel and about as
thick. *...

How about making aluminum soft jaws for your milling vise with a
shallow horizontal vee notch in the top edges, or a few dowel pin
holes?

"Ivan Vegvary" wrote in message
...
I volunteered to fix a bunch of older Vemco drafting machines (elbow type)
for the local high school. A frequent fault is that the graduated base
plate can no longer be clamped by the "Protractor Brake". Said brake is
simply a thin piece of aluminum with a shoulder that pinches (clamps) down
on the protractor. It is approximately the size of a nickel and about as
thick. I successfully filed 0.007 inches of one side, however, it is a
difficult task freehand and removes a lot of skin from the fingertips.
If it weren't aluminum, I would simply place it on my magnetic chuck.

One thought I had was to carve a recess into a block of wood and use that
as a work stop. An advancement would be to drill a hole into said block
of wood and use either my vacuum pump or mighty-vac to hold the part down.
Could also make in impression in a chunk of clay, but SWMBO says it would
take at least 24 hours to fire in her huge kiln.

Other ideas appreciated.

Ivan Vegvary

Paste wax an area on your mill table, and one of the subject parts with a
good heavy duty paste wax. Mold release wax is premium, as sold by fiber
glass venders.

Lay the part down on the side you wish to machine.

Lag the part up with body filler, or tooling plastic. Modeling clay can be
used if necessary to stop the plastic from getting under the part in areas
that would trap and lodge the part in the cured plastic mold.

Upon hardening, gently clamp the mold as is, and machine the back flat with
well used tool. Body filler and tooling plastics are most often very
abrasive.

Flip it over, clamp it down, and machine the part.

Pop out the part, replace with another, and repeat.

Ivan Vegvary wrote:
I volunteered to fix a bunch of older Vemco drafting machines (elbow
type) for the local high school. A frequent fault is that the graduated
base plate can no longer be clamped by the "Protractor Brake". Said
brake is simply a thin piece of aluminum with a shoulder that pinches
(clamps) down on the protractor. It is approximately the size of a
nickel and about as thick. I successfully filed 0.007 inches of one
side, however, it is a difficult task freehand and removes a lot of skin
from the fingertips.
If it weren't aluminum, I would simply place it on my magnetic chuck.

One thought I had was to carve a recess into a block of wood and use
that as a work stop. An advancement would be to drill a hole into said
block of wood and use either my vacuum pump or mighty-vac to hold the
part down.
Could also make in impression in a chunk of clay, but SWMBO says it
would take at least 24 hours to fire in her huge kiln.

Other ideas appreciated.

Ivan Vegvary
Mount it on a wooden dop with sealing wax then either clamp that or work
freehand with a decent handle. Heat to release. Might need a few brass
panel pins with their heads just lower than the surface of the part
round the edge to resist lateral forces, but it's gotta be easier than
carving a pocket and wax will clean off easier at a lower temperature
than superglue. I've lapped dozens of copper seal washers I annealed
for reuse that way last time I rebuilt a diesel.

--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk
[at]=@, [dash]=- & [dot]=. *Warning* HTML & 32K emails -- NUL:

Machine a pocket in a 5C emergency collet to hold the part and face off the
part in your lathe.

"Ivan Vegvary" wrote in message
...
I volunteered to fix a bunch of older Vemco drafting machines (elbow type)
for the local high school. A frequent fault is that the graduated base
plate can no longer be clamped by the "Protractor Brake". Said brake is
simply a thin piece of aluminum with a shoulder that pinches (clamps) down
on the protractor. It is approximately the size of a nickel and about as
thick. I successfully filed 0.007 inches of one side, however, it is a
difficult task freehand and removes a lot of skin from the fingertips.
If it weren't aluminum, I would simply place it on my magnetic chuck.

One thought I had was to carve a recess into a block of wood and use that
as
a work stop. An advancement would be to drill a hole into said block of
wood and use either my vacuum pump or mighty-vac to hold the part down.
Could also make in impression in a chunk of clay, but SWMBO says it would
take at least 24 hours to fire in her huge kiln.

Other ideas appreciated.

Ivan Vegvary

on 3/12/2009, Ecnerwal supposed :
In article ,
"Ivan Vegvary" wrote:

Could also make in impression in a chunk of clay, but SWMBO says it would
take at least 24 hours to fire in her huge kiln.

And after it was fired, the part wouldn't fit - clay shrinks when fired.

Thin (not thick and foamy) double-stick tape might do perfectly well, if
the parts are clean and flat. The superglue already suggested would also
work. If the part is prone to creep during filing despite the tape, a
couple of stops to catch the edge of the plate might be all the help it
needs.

Hot glue is yet another option. Fixturing alloy would be another.

Agreed.
I've had good luck with double sided sticky and light cuts.

Wayne D.

Thanks everybody!!

I decided to try the thin double sided tape idea first. (BTW the part is
not round so some of the replies would not work). Milled a thin slot across
a 1" x 0.1" piece of aluminum. Slot depth approximately 0.025" deep.
Simply enough to give me a shoulder against which the part will abut while I
push the file. Used thin scotch brand double sided tape. Worked like a
charm. Merely sliding the file across 4-5 times, I removed almost 0.010
material. Was shooting for 0.007±. Very fast. Takes longer to find the
end of the scotch tape than to complete the project.
It surprised me that I could even file backwards, whereby only the tape was
holding the part i.e. no shoulder for the part to rest against.

Thanks!!!!!!!!

Ivan Vegvary

On Thu, 12 Mar 2009 12:32:46 -0700, "John R. Carroll"
wrote:


"Ecnerwal" wrote in message
...
In article ,
"Ivan Vegvary" wrote:

Could also make in impression in a chunk of clay, but SWMBO says it would
take at least 24 hours to fire in her huge kiln.

And after it was fired, the part wouldn't fit - clay shrinks when fired.

Thin (not thick and foamy) double-stick tape might do perfectly well, if
the parts are clean and flat. The superglue already suggested would also
work. If the part is prone to creep during filing despite the tape, a
couple of stops to catch the edge of the plate might be all the help it
needs.

Hot glue is yet another option. Fixturing alloy would be another.

I've got a bunch of Indium/Bismuth that would be perfect - it shrinks
.0002"/" after an hour and the eutectic temp. is 136F.
The trouble is that it's $80.00/lb but I might make a send out a half pound
as a courtesy. I think that would be enough and it's reusable.

JC

That's a very nice courtesy!

On Thu, 12 Mar 2009 18:34:35 GMT, "Ivan Vegvary"
wrote:

I volunteered to fix a bunch of older Vemco drafting machines (elbow type)
for the local high school. A frequent fault is that the graduated base
plate can no longer be clamped by the "Protractor Brake". Said brake is
simply a thin piece of aluminum with a shoulder that pinches (clamps) down
on the protractor. It is approximately the size of a nickel and about as
thick. I successfully filed 0.007 inches of one side, however, it is a
difficult task freehand and removes a lot of skin from the fingertips.
If it weren't aluminum, I would simply place it on my magnetic chuck.

One thought I had was to carve a recess into a block of wood and use that as
a work stop. An advancement would be to drill a hole into said block of
wood and use either my vacuum pump or mighty-vac to hold the part down.
Could also make in impression in a chunk of clay, but SWMBO says it would
take at least 24 hours to fire in her huge kiln.

Other ideas appreciated.

Ivan Vegvary

Lapidaries grind and polish rocks freehand. They use dop wax.
http://www.gravescompany.com/adhesive.htm

Hey Ivan,

Glad it worked out for you. Me??? I had no idea what to do!!!
BUUUTTT.... I do hope to catch at least one of the NAMES SEMINARS in
mid April which would seem to be of interest to you and many of us:

Noon Saturday...
Jerry Kieffer "SILVER SOLDERING & FABRICATING SMALL PARTS"

and at 4PM..
Ron Grimes "WORKING WITH SMALL CASTINGS AND PARTS".

Take care.

Brian Lawson,
Bothwell, Ontario.
XXXXXXXXXXXXXXXX

....On Fri, 13 Mar 2009 05:19:18 GMT, "Ivan Vegvary"
wrote:

Thanks everybody!!

I decided to try the thin double sided tape idea first. (BTW the part is
not round so some of the replies would not work). Milled a thin slot across
a 1" x 0.1" piece of aluminum. Slot depth approximately 0.025" deep.
Simply enough to give me a shoulder against which the part will abut while I
push the file. Used thin scotch brand double sided tape. Worked like a
charm. Merely sliding the file across 4-5 times, I removed almost 0.010
material. Was shooting for 0.007±. Very fast. Takes longer to find the
end of the scotch tape than to complete the project.
It surprised me that I could even file backwards, whereby only the tape was
holding the part i.e. no shoulder for the part to rest against.

Thanks!!!!!!!!

Ivan Vegvary

"Don Foreman" wrote in message
...
On Thu, 12 Mar 2009 18:34:35 GMT, "Ivan Vegvary"
wrote:

I volunteered to fix a bunch of older Vemco drafting machines (elbow type)
for the local high school. A frequent fault is that the graduated base
plate can no longer be clamped by the "Protractor Brake". Said brake is
simply a thin piece of aluminum with a shoulder that pinches (clamps) down
on the protractor. It is approximately the size of a nickel and about as
thick. I successfully filed 0.007 inches of one side, however, it is a
difficult task freehand and removes a lot of skin from the fingertips.
If it weren't aluminum, I would simply place it on my magnetic chuck.

One thought I had was to carve a recess into a block of wood and use that
as
a work stop. An advancement would be to drill a hole into said block of
wood and use either my vacuum pump or mighty-vac to hold the part down.
Could also make in impression in a chunk of clay, but SWMBO says it would
take at least 24 hours to fire in her huge kiln.

Other ideas appreciated.

Ivan Vegvary

Lapidaries grind and polish rocks freehand. They use dop wax.
http://www.gravescompany.com/adhesive.htm

friend of mine polishes facets on glass chunks (up to about 50lbs apiece) by
embedding them in a puddle of paraffin, using a vibrolap, then gently
heating them up to get the paraffin off.