# Familiar with Pantograph?



## oskar (Dec 18, 2018)

Lots of info on the Internet about Pantographs but there is nowhere to explain how I can find my own ratio. I’m talking about a simple Pantograph which is made with 1”x2” lumber.

I want to use it to engrave with my Dremel some labels on plastic for my little shop and I know which legs on the Pantograph I have to drill my pins but I don’t know the distance.

So if my letter templates are 1/4” high and I want to engrave them having 1/2” high, as an example, how do I find the required pins location on the Pantograph?

I can do it by trial and error but it will be much better if I know the simple maths behind it


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## JimDawson (Dec 18, 2018)

Maybe this will help.  https://en.wikipedia.org/wiki/Pantograph


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## Dabbler (Dec 18, 2018)

I've tried to study the maths involved, and didn't get much traction.  Let me know what you find!

My pantograph only does reduction, so I can't look up the ratios for you.


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## oskar (Dec 18, 2018)

JimDawson said:


> Maybe this will help.  https://en.wikipedia.org/wiki/Pantograph



Thanks Jim, I have this and it does not tell you how to find your own ratios


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## Dabbler (Dec 18, 2018)

This won't 'exactly' answer your question, but this video might help:

joe Pieczynski's pantograph plans

He has a series on making your own pantograph on the mill. I forgot that if you are using a home made pantograph you can put the stylis/grinder in either location, so I'll look up the .5 reduction on my machine.


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## JimDawson (Dec 18, 2018)

oskar said:


> Thanks Jim, I have this and it does not tell you how to find your own ratios



True, but the picture does


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## Dabbler (Dec 18, 2018)

Jim is referring to this picture:

link


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## oskar (Dec 18, 2018)

Dabbler said:


> This won't 'exactly' answer your question, but this video might help:
> 
> joe Pieczynski's pantograph plans
> 
> He has a series on making your own pantograph on the mill. I forgot that if you are using a home made pantograph you can put the stylis/grinder in either location, so I'll look up the .5 reduction on my machine.



I will study this one, thanks


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## oskar (Dec 18, 2018)

JimDawson said:


> True, but the picture does



Got it Jim, thanks. So is the ratio of 6+6=12/6=2 and thats why its a 2x pantograph


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## Doug Macleod (Dec 18, 2018)

Your pantograph ratio is the distance stationary mount to stylus as the distance of the stylus to the pencil.  It is the hypotenuse of the triangle that determines to ratio.  The hypotenuse being the line from the pencil through the stylus to the stationary mount.


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## petertha (Dec 19, 2018)

Here are some links I've saved in the 'future projects' file. PDF plans are downloadable. 
http://imageevent.com/tomgriffin/pantograph
http://bbs.homeshopmachinist.net/threads/46469-Get-a-grip-with-a-3D-pantograph!?highlight=pantograph

Coincidentally I am looking at some Ebay spindle motors in the 600watt 12,000 rpm class with included power supply / variable speed control & ER integrated collet. Shallow, light engraving you could probably get away with less power.


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## oskar (Dec 19, 2018)

Doug Macleod said:


> Your pantograph ratio is the distance stationary mount to stylus as the distance of the stylus to the pencil.  It is the hypotenuse of the triangle that determines to ratio.  The hypotenuse being the line from the pencil through the stylus to the stationary mount.



Thanks Doug, that's what I was looking for


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## oskar (Dec 19, 2018)

petertha said:


> Here are some links I've saved in the 'future projects' file. PDF plans are downloadable.
> http://imageevent.com/tomgriffin/pantograph
> http://bbs.homeshopmachinist.net/threads/46469-Get-a-grip-with-a-3D-pantograph!?highlight=pantograph
> 
> Coincidentally I am looking at some Ebay spindle motors in the 600watt 12,000 rpm class with included power supply / variable speed control & ER integrated collet. Shallow, light engraving you could probably get away with less power.



Excellent links petertha, thanks

Good idea the 600W spindle with motor. I have a Dremel tool I got years ago from Canadian Tire as a set including many attachments. Among the attachments there is a flex shaft about 16” long which I never used but it will be quite handy for the pantograph because I can only attach the end of this shaft to the pantograph which is very small and light. For small engraving will be ideal but anything more complicated may not do the job.

I made a pantograph out of paper first to get the idea and next step is to do it in 1/16” pressboard. The final will be with 1”x2” lumber but the links you sent may change my mind and do it in aluminum. Much appreciated


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## petertha (Dec 19, 2018)

No problem. I've made some similar pantograph like contraptions for hotwire foam cutting many moons ago when I had less for machining resources. On those I used 1.25 x 1.25 square section aluminum tubing 0.125" w.t. The swivel joints were pressed in nylon or bronze bushings and ground shaft pins. Nice snug fits with smooth action & all pretty inexpensive stuff really. The stiffness comes from the frame cross section depth, it may not necessarily have to be solid bar. Now this was a pretty low load setup so supporting a motor & possible vibration brings up new considerations. Mocking things up with wood or whatever you can quickly flush out ideas & problems is a good thing IMO.

An interesting concept is adding rotational component - tables or platens between model & pattern. Its kind of 2.5D that can yield 3D-ish copying or scaling. The mechanism gets a bit more complicated because the stylus/cutter also has to be scaled & move according to the same scaling geometry mentioned above.


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## oskar (Dec 19, 2018)

petertha said:


> No problem. I've made some similar pantograph like contraptions for hotwire foam cutting many moons ago when I had less for machining resources. On those I used 1.25 x 1.25 square section aluminum tubing 0.125" w.t. The swivel joints were pressed in nylon or bronze bushings and ground shaft pins. Nice snug fits with smooth action & all pretty inexpensive stuff really. The stiffness comes from the frame cross section depth, it may not necessarily have to be solid bar. Now this was a pretty low load setup so supporting a motor & possible vibration brings up new considerations. Mocking things up with wood or whatever you can quickly flush out ideas & problems is a good thing IMO.
> 
> An interesting concept is adding rotational component - tables or platens between model & pattern. Its kind of 2.5D that can yield 3D-ish copying or scaling. The mechanism gets a bit more complicated because the stylus/cutter also has to be scaled & move according to the same scaling geometry mentioned above.



Thanks for the info petertha

I was searching for a simple inexpensive jig to make simple engraving for tags etc. and I came up a few days back with the pantograph. It looks very simple to make and I guess eventually I will come up with own version which will be good for my needs.

It will be a nice winter project and when I finish I will post it here


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## whitmore (Dec 19, 2018)

[QUOTE="petertha, post: 631328, member: 40364"... I am looking at some Ebay spindle motors in the 600watt 12,000 rpm class with included power supply / variable speed control & ER integrated collet. Shallow, light engraving you could probably get away with less power.[/QUOTE]

For engraving, of course, end play is important; how much is to be expected from those prebuilt spindles?   Can they
be shimmed?   Or, would you have to mount a depth stop onto the moving part?


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## petertha (Dec 19, 2018)

Great question(s). I haven't pulled the trigger yet so cant help. Here is something like I was looking at on Ebay. I'v eseen several generic looking ones with different combinations of power supply & motor specs. They say "_*spindle run out: about 0.01-0.03*_" which is mm, which is 0.0004 to 0.0012". I guess I'm suspicious of this claim. I don't see any reference to bearings or internal features. It comes from the land of official looking stamped inspection certificates that don't necessarily correspond to actual TIR. Looks like they sell them predominantly to the home CNC crowd as lower power spindle motors.

OTOH, I think you'd be hard pressed to build a pantograph assembly with all those pivots & joints & geometric spacing's & keep the collective tolerance under a thou. So my guess is that may well trump the motor TIR. All depends on what you are doing. Its not going to be a Deckel.

https://www.ebay.ca/itm/600W-ER16-D...h=item2ca31aff16:g:5KEAAOSw8gVX~de3:rk:4:pf:0


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## oskar (Dec 20, 2018)

petertha said:


> Here are some links I've saved in the 'future projects' file. PDF plans are downloadable.
> http://imageevent.com/tomgriffin/pantograph
> http://bbs.homeshopmachinist.net/threads/46469-Get-a-grip-with-a-3D-pantograph!?highlight=pantograph
> 
> Coincidentally I am looking at some Ebay spindle motors in the 600watt 12,000 rpm class with included power supply / variable speed control & ER integrated collet. Shallow, light engraving you could probably get away with less power.



Peter have you noticed the Pantograph described in this link?
https://www.hobby-machinist.com/threads/community-build-2-signup-for-pantograph.4989/

Do you see any pros / cons between the two?


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## petertha (Dec 20, 2018)

No, I hadn't seen that design. Good for you using the search button! The base & pillar & overall mechanism looks more like the classic engraving machines & the article kind of infers that's what the designer was leveraging off of. There is definitely more metalworking involved. Notice it has a self-constructed spindle with bearings & separate drive motor. That's likely to increase rpms over what typical motors could turn 30-odd years ago & control rpm. I would have to think the Chinese cnc motors with integral ER chucks could do this. Now whether the 12-13K rpm is what the cutters require I can't say, might have to check some engraver specs. The mechanism looks a bit more compact so possibly might hold tolerance better but also more limited in work space & ratios?

I guess when in doubt make the simpler and/or cheaper of the two. But the medallion that the fellow engraved for his pistol looks pretty good to my untrained eye. I guess the question is - what is the intended purpose? If its 'art' like fonts or graphics, nobody will know. If you are machined parts by replication of patterns & have to be within a thou, that's a different matter.


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## oskar (Dec 20, 2018)

If I go this way I just plan to use just the arms design which looks simpler and the rest will be my own design support / Dremel. I did an enlarged (x2) sample of the arms with 1/4” thick pressboard and the geometry works well (no cutting or anything else).

But the one from Tom Griffin is also a pretty good one and I also plan to make a sample to see the deference between the two.

There is also another interesting one by Joe Pieczynski. On the link click to download the 12 pages .PDF. My choice will be one of the 3

https://www.advancedinnovationsllc.com/plans


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## oskar (Dec 26, 2018)

I did a rough working pantograph sample based on the links from post 11 and I can’t figure out the ratios provided on the drawings. Perhaps someone can help me here to find out for example how the 1:10 ratio is provided?


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## oskar (Dec 28, 2018)

It turns out that I was not wrong calculating the 1:10 ratio because I learned the ratios shown on the drawings from post 11 are backwards!

So the 1:10 ratio is actually 2:1 (like I figured out) and the other ratios 1:2, 1:3, 1:4, 1:6 are actually 10:1, 6:1, 4:1, 3:1.


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