LocostUSA.com

has anyone build a plasma copier,

like a pantograph or a double T

_________________
this story shall the good man teach his son,
and chrispin chrispian shall ne'er go by,
from this day to the end of the world.
but we in it shall be remembered.

I think in Ye Moderne Tymes, most folks take the CNC plunge instead of mechanical copying, but there's no reason I can think of that a pantograph wouldn't work just fine, and it's probably be a couple thousand bucks cheaper to make than DIY CNC.

Check out post #30 for an interesting concept for a metal-cutting pantograph:

http://www.tractorbynet.com/forums/buil ... ost3221111

_________________
Locost builder and adventurer, and founder (but no longer owner) of Kinetic Vehicles

Found this with a search...

https://www.youtube.com/watch?v=RcaiRfYGY-I

_________________
+442 - Miata

the problem with cnc machines is that they are so expensive to build,

when i need to make some parts i often make a cardboard pattern then trace it onto a piece of steel plate or aluminum, then cut it out.

if this works the way it should, i could do the tracing and cutting part in one hit.

and the cost would be a couple of hundred bucks at the most not a couple of thousand.

i think that setup may take a bit of getting used to but i'm sure it can be done.

_________________
this story shall the good man teach his son,
and chrispin chrispian shall ne'er go by,
from this day to the end of the world.
but we in it shall be remembered.

What's nice about pantographs is that you can increase the scale, and doubling the scale doubles the accuracy. If I want a 1" dia. hole with a tolerance of plus or minus 0.01" and my pantograph can trace a 2" circle with plus or minus 0.01", my 1" hole will be plus or minus 0.01" x 1/2 = 0.005"

Bo

Pics please?

_________________
Locost builder and adventurer, and founder (but no longer owner) of Kinetic Vehicles

No pics, just theory (my "theoretical" pantograph).

I always planned to build one and learned: The pieces have to be accurately drilled - clamp them together and match drill the holes. Doesn't matter what their spacing is so long as it's identical between the pieces. Joints have to be free of all play. I had planned to use countersunk screws with nylon washers between the pieces to snug them up for zero play but still free to move. Partially thread the pieces receiving the screws so there is no play in the screws.

bo

Forgot to mention:

For holes, I was going to put a turnbuckle on the tracing point to adjust the radius.

o.k. try this, make a "T" with the top bar pivoted in the middle where it attaches to the vertical.

now fix the bottom of the "T" to the bench.

fix a pencil on one end of the top bar.

fix a scribe to the other end of the top bar.

place a pattern under the scribe and follow the pattern.

you will see that the pencil has reproduced the pattern but in reverse.

now joint two "T's" together as in "TT" place the pencil on the left outer end of the top bar.

join the top bars of the "T's" together.

place the scribe on the right hand end of the top bar.

fix the bottoms of the "T's" to the bench.

now the pattern will be reproduced in the correct orientation.

if the scribe can be slid along its leg of the "T" towards the vertical, then the reproduction will get larger than the pattern, likewise if the pencil can be slid along the top arm towards the vertical, the reproduction will be smaller than the pattern.

with the bottom of both verticals attached to the bench it is much sturdier than a conventional pantograph.

if it doesnt matter if the reproduction is reversed or you need a left and right hand reporoduction then use one "T" for the opposite hand.

more to come

_________________
this story shall the good man teach his son,
and chrispin chrispian shall ne'er go by,
from this day to the end of the world.
but we in it shall be remembered.

Great idea John!

I'm scrapping my plans for a parallelogram pantograph for the "Model T".

I've seen carburetor swivel joints used in pantographs because they have zero play. That would work well in a T arrangement.

Bob