www.TK560.com

jegner · Posted: Mon Sep 24, 2007 10:16 am Post subject: Pantograph Machine

After reading about the CNC machine, what about a lower tech approach to duplicating parts? Back before computers took over the world, artist use a tool called a pantograph to make copies of master patterns, and these are actually pretty simple. Google shows up a few options:

http://www.wood-carver.com/ shows a commercially produced machine.

http://www.copycarver.com/ is a site where you can see a DIY version. Plans are for sale, not free.

http://www.mepd.net/forum/viewtopic.php?t=2651 is a project done with a knock off version of the copy-carver. http://www.doomlegends.com/deimwolf/mg34model.html#01-05-2007

And a video: http://video.google.com/videoplay?docid=-2413717528443348681&hl=en shows a propeller being duplicated.

drcrash

There are a lot of things that are often called "pantographs". Some of them are used for making 1:1 copies, and some for scaling things up and down.

Try doing web searches for "3D pantograph," "Collas Machine," and "Cheverton Machine."

A pantograph is a system of four levers that keeps three points in a line, and in the same ratio of distances from each other. Most pantographs are 2D, but they work in 3D if you have rigid levers, and pivots that keep them in a plane. Given a pantograph like that, you can put it on a universal joint and use it to scale 3D shapes up or down, or scale and invert them (from positive to negative. It all depends on which of the 3 points you use to attach the universal joint (at a fixed point) and which you use for the probe or the cutter.

The Sears Craftsman Deluxe Router pantograph is a limited 3D pantograph. In normal use, it's only good for relief carvings up to about an inch deep, and only lets you reduce things (to 40, 50, or 60 percent) but you can do some perverted things with it. (If you extend the u-joint mount, probe, and cutter a few inches out of the plane of the pantograph, and mount a lightweight low-kickback cutter on it, you can do a fair bit of stuff.)

A Collas machine is a different thing that uses a simple lever on a universal joint (I think), and a pair of synchronized turntables. (Using gears or sprockets and a chain or whatever.) You can move a probe attached at one point on a lever, moving it in and out or up and down to scan over a model, and a cutter at another point which will move proportionally. By itself, that would only give you an arc, but if you rotate the model and the copy (blank) you can do full 3D shapes in the round.

Most of Rodin's sculptures were scaled up/and or down from macquettes (terra cotta, I think) using a Collas machine.

A Cheverton machine is sorta like a Collas Machine, only instead of using a simple lever, you use a pantograph in combination with synchronized turntables. That lets you do not only full 3D in the round, but some fairly serious undercuts, because you can come at the work from different directions with the probe and cutter.

Cheverton machines were used to produce lots of sculptures in the 19th century.

Cheverton machines are way cool.

I think the ancient Greeks and Romans used simple pantograph "pointing machines" to guide the scaling of sculptures up and down. (With manual cutting.) Medieval artisans used them a lot, to make gargoyles for cathedrals and stuff like that.
_________________
Paul (a.k.a. Dr. Crash)

Tired of buying cheap plastic crap? Now you can make your own! www.VacuumFormerPlans.com

jegner · Posted: Mon Sep 24, 2007 1:56 pm Post subject:

The Cheverton-Hawkins 'reducing' machine might be a way to scale down armor molds for youth sizes. Cool stuff.

Fixed typo.

Jim

drcrash

I dunno if these are useful, but they're kind of interesting.

Here's some plans for a 1:1 duplicator for wood carvings:

and this thread from a slot car forum has some plans for a little 3D pantograph for scaling stuff:

http://www.slotforum.com/forums/blog/manitouguy/index.php?cat=56&st=5

Go down to the bottom of the page (page 2) and there's a posting with five links to page images of an old magazine article.
_________________
Paul (a.k.a. Dr. Crash)

Tired of buying cheap plastic crap? Now you can make your own! www.VacuumFormerPlans.com

drcrash · Posted: Tue Sep 25, 2007 12:34 pm Post subject:

fast_monte · Novice Joined: 17 Aug 2005 Posts: 40

Has anybody built a 3-D pantograph? I want to make a 1/10th scale R/C car body from a 1\24th die cast model.

jegner · Posted: Mon Feb 25, 2008 11:45 am Post subject:

Something I should try. I have most of the parts needed for this sort of thing... Except time.

fast_monte · Novice Joined: 17 Aug 2005 Posts: 40

By following this link provided by drcash
http://www.slotforum.com/forums/blog/manitouguy/index.php?cat=56&st=5 I found that the link needed to be updated so here it is
http://www.slotforum.com/forums/index.php?automodule=blog&blogid=47&showentry=481 Manitouguy has a bunch of great slot car stuff on his blog and it should be checked out. He desirves the credit for the following picures.

With that being said the article does not go into the math on how to adjust the scales. I want to scale up a model by a scale of 2.2667:1

Does anyone have an idea on how to do the math for a pantagraph configured in the manor shown above?