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View Full Version : OT - Mechanical Drawing Device Identification



BigBoy1
04-27-2015, 10:05 AM
I was going through my father's mechanical drawing stuff and came across this device. I think it was used to enlarge/reduce drawings. I'd like to know it exact name and brief description of how it works. Would anyone just happen to have a users manual for it? Appreciate any assistance. Thanks.

https://lh3.googleusercontent.com/c9YHfzeP_pakbVoFNKMmWmlwGKOnkWaqIbEGsbnnNA=w276-h207-p-no

https://lh3.googleusercontent.com/-w_1LNet_o3kknyoErJXvRTqCbOX1D-cwlmQ4Q48lg=w276-h207-p-no

https://lh3.googleusercontent.com/gA61Uc4W-eS-vZza1QDGnsfhBbZeyBgDBcwc791z5A=w276-h207-p-no

https://lh3.googleusercontent.com/YJvrie5yhS0RPEKB4_XE0fbVl4NgDEjAaED2t31Kow=w276-h207-p-no

Doozer
04-27-2015, 10:11 AM
Pantograph.

-D

JCHannum
04-27-2015, 10:15 AM
It is a drafting pantograph, used to copy, enlarge or reduce drawings. Google will turn up examples and instructions for use. They are still available on today's market.

mklotz
04-27-2015, 10:16 AM
It's called a pantograph. You clamp one joint to the table, trace the drawing to be copied with the stylus and the pencil point traces out the enlarged/reduced copy. The holes through which the arms are pivoted determine the scale.

I've never seen a manual for one. It's too simple a device to warrant a manual. Anyone with mechanical sense should be able to puzzle it out.

EddyCurr
04-27-2015, 10:44 AM
This link might prove helpful


https://www.youtube.com/watch?v=r0UZHFUM7ow

.

Paul Alciatore
04-27-2015, 11:24 AM
I can't read the numbers on the arms with your small photos, but they are probably the various ratios that it is able to do. You should use the same number on all four arms for it to work properly. One point is for tracing an existing drawing and the other one has a pencil or pen to draw the new one at a different scale. They should be reversible. The third one has a stud in it to help it to glide above the drawings instead of flopping on them and dragging. That stud should probably stay where it is. That's about it for instructions.

I have never used one, but I would think it may be best to use it to pick up center and end points on the drawing and use ruler and compass to do the actual drawing between them for the best appearance.

BigBoy1
04-29-2015, 11:15 AM
Appreciate the help. I couldn't think of Pantograph for the life of me.

boslab
04-29-2015, 12:02 PM
As you said, if you trace along a rule and square the result is better, also making a big one is handy with a plasma torch
There's another similar gadjet, a planimeter or compensating planimeter, handy for areas
Mark

MaxHeadRoom
04-29-2015, 12:31 PM
And to think now, AutoCad does it to a whole drawing at the click of a mouse!
Max.

The Artful Bodger
04-29-2015, 03:41 PM
The last time I saw one being used it was huge and something obviously cobbled up for the job, it was being used to place the outline of a transport company's logo on the side of their building. I dont think AutoCad could do that?

MaxHeadRoom
04-29-2015, 03:56 PM
Correct, but that is not a drawing, I would have thought that a projected image would also have worked for a building?
In AutoCad you generally always draw in full scale, so all actual dimension can be taken off very easily, if necessary.
Max.

Mike Burch
04-29-2015, 07:07 PM
About half a century ago, the shop I worked in had a pantograph engraver for making labels. Instead of a pencil it had a wee high-speed burr, and the follow pin moved in grooves in letters set up in a frame. Lifting the follow pin also lifted the burr.
The thing was used to engrave labels in that wierd plastic that has different coloured layers. Milling off the top layer allows the contrasting colour to show through. The resulting labels are quite neat.
I think these gadgets still exist. I've seen one used to achieve the same result using aluminium with coloured anodising.

AD5MB
04-29-2015, 07:42 PM
the old school equivalent of a pantograph for putting logos on large areas was the slide projector. drive a van into the shop, project a slide of the logo, mask, spray.

alanganes
04-29-2015, 07:51 PM
The thing was used to engrave labels in that wierd plastic that has different coloured layers. Milling off the top layer allows the contrasting colour to show through. The resulting labels are quite neat.
I think these gadgets still exist.

They do, but I'd guess that they are less common now that small cnc engravers are more available. So does that plastic material. It is still in use for some stuff, you still see it around on industrial control panels and the like. Some generically refer to it as "lamicoid" though that is a brand name I guess. Like this:

https://www.google.com/search?q=lamicoid&tbm=isch&tbo=u&source=univ&sa=X&ei=uG1BVaXjNsbQtQX9toCgCg&ved=0CDIQsAQ&biw=1252&bih=614#tbm=isch&q=lamacoid&spell=1

The Artful Bodger
04-29-2015, 08:07 PM
Correct, but that is not a drawing, I would have thought that a projected image would also have worked for a building?


....the old school equivalent of a pantograph for putting logos on large areas was the slide projector.

Be that as it may, in this case they chose to tape up a small drawing and were using a pantograph to transfer an enlarged version to the wall. If I ever see them doing it again I will be sure to tell them they are doing it all wrong.

Circlip
04-30-2015, 06:57 AM
Wickman "OPG" ( optical profile grinder ) used a reverse pantograph, Drawing was prepared at 25 x full size. "Paper" was metal foil sandwiched between top and bottom layers of high quality drawing paper ( Stability ) and finished drawing was clipped to a table on the machine under the stylus of a 25 : 1 reduction linkage coupled to an optical microscope looking on edge of a vertically reciprocating diamond bonded metal grinding wheel. At that time, 50 years ago, the wheel was 60. DAMHIFK. :o

Regards Ian.

boslab
04-30-2015, 07:25 AM
the old school equivalent of a pantograph for putting logos on large areas was the slide projector. drive a van into the shop, project a slide of the logo, mask, spray.
It an epidiascope, also was used to project the letraset catalog onto sheet Perspex for cutting out with fretsaw to make shop signs.
I remember catching a bloody big spider and putting it under the projector, we then called the girl from the office, who walked into the cutting and bevelling room, saw a giant spider on the wall and wet herself, cruel I know, the spider was unharmed btw!
Mark