Electrical Pencil Arcograph

[Klaus]

Hello everybody,

I try to built this.


http://www.vintageprojects.com/general-workshop/etching-pen-plans.pdf



What means 20 ga. for the spring bronce i think it´s the thickness ? Also how is the diameter of the 16 D Nail?

Klaus

 

[Cogsy]

The 20 ga. is 20 gauge brass (0.032 inches / 0.80mm thick). The nail is 0.165 inch / 4.2mm diameter and 3.5 inches / 89mm long.

I have trouble with all the 'old school' designations as well, why isn't the whole world metric .

The pencil looks cool, might have to have a go at one myself one day.

 

[Klaus]

Hi Cogsy,
thanks for the quick reply. Now it starts to get winter = workshop time! Lets start!

Regards Klaus

 

[modeng2000]

This marking pen really works but there seems to be a knack to be able write smoothly.
I have made one that is very similar. I used a thin tungsten rod as used with some welders for the stylus.

John

 

[Swifty]

Had a couple of shop bought ones over the years, and they all had tungsten nibs. They just ran off a small transformer, occasionally the nib would weld itself onto the piece being marked, then it started to glow red hot.

Paul.

 

[Gedeon Spilett]

Two days ago, I was doing some repairs on electric Hornby locos (yes tinplate toys I confess) , the sparks produced by the transfomer (20V AC, 20W) easily labeled the surface of most of the pieces of metal I touched.
I did a quick test, and in fact, it was not at all easy to obtain a continuous and regular line, not to mention really write.

 

[BaronJ]

Hello everybody,

I try to built this.


http://www.vintageprojects.com/general-workshop/etching-pen-plans.pdf



What means 20 ga. for the spring bronce i think it´s the thickness ? Also how is the diameter of the 16 D Nail?

Klaus

Hi guys,
I note that there are no dimensions given for the length of the coil !

I have an original etch pen from 60 years ago that runs from a transformer that supplies about 6 volts. The coil in mine is about a half inch in diameter and around 3.5 inches long. The tip looks like an old fashioned gramophone needle. It works surprisingly well, even today despite its age.

If wanted I can take a photograph or two.

 

[deverett]

Hi guys,
... If wanted I can take a photograph or two.

Photos are always welcome. As they say: a picture is worth 1000 words.

Dave
The Emerald Isle

 

[BaronJ]

Photos are always welcome. As they say: a picture is worth 1000 words.

Dave
The Emerald Isle

No Problem !
Watch this space...

 

[modeng2000]

Watching

 

[Shopguy]

Hi guys,
This a picture of an electric arc pen that I made as a shop project in grade 10 50 years ago. The principle is the same as the one being talked about. Requires a steady hand to use. The coil is about 8 cm long and wound rather loosely around a nail of similar length. The steel guide that the tip of the copper wire passes through is insulated from the electrical conduit body. It works well on 6 volts AC or DC. Also in that class we made our own step down transformer. Unfortunately I don't still have it.

 

[BaronJ]

No Problem !
Watch this space...

As promised.

The top of the black Bakelite handle is just over 5/8" diameter and the stylus is 1/2" long. Its held in place by the 10BA cheesehead screw.

I got the transformer voltage wrong its 5 volts. It was the 6 volt battery bit I remembered. However it does seem to work better from the transformer which produces AC. The output is not rectified.

The coil inside is not wound on a former and is a quite heavy gauge wire. I would guess 20swg and seems to be in several layers. The top part screws into the Bakelite handle and the coil is attached by a small screw into the flat surface inside.

Baron.

 

[modeng2000]

Thanks Shopguy and Baron, as these seen fairly straight forward to make I wonder if many of them are in use today.

John

 

[BaronJ]

Thanks Shopguy and Baron, as these seen fairly straight forward to make I wonder if many of them are in use today.

John

I wouldn't think so ! Mine is only in such good condition because its spent the vast majority of its life in a box in a storeroom.

A Dremal with a diamond burr does the same job and its more likely to be on hand when needed.

 

[deverett]

Many thanks for the description and pics. Anyone who wants to make one should be able to do so from your description and the originally linked article.

Dave
The Emerald Isle