Etcher/marker

[ajoeiam]

Hi Gordon, Guys,

Some more pictures of the inside of my ActoGrap pen.

snip

I've started to draw this up with accurate dimensions which I will post later.

Following!!!!!!!!!!!!!

 

[cds4byu]

After spending a bunch of time looking at these tools, I wondered about making an electronically controlled version rather than an electromechanically controlled one.

Commercial products I found ranged from 500W to 2500W. This is a lot more than the 25W you have found in hour system.

25W is really easy to do with a MOSFET. 500W at 5 V is just a bit harder.

How important is the vibration of the tip? If the current were interrupted, could it work without the tip vibrating?

Carl

 

[RM-MN]

How important is the vibration of the tip? If the current were interrupted, could it work without the tip vibrating?

Making and breaking the contact is spark eroding. Without the tip being moved from the contact it is called welding.

 

[BaronJ]

That does not look like it justifies the $500 price the present day ActoGraph unit sell for. MSC sells one for $498 but they also list a spare ground cable for $61 and that is nothing but a piece of wire with an alligator clip. It looks like it should be fairly easy to make one.

It looks like there are contact points on the end of the coil. I assume that means it acts as kind of a buzzer/vibrator in operation.

Thank you for your efforts. Looks like I may have another to do project. I am looking forward to a more detailed drawing.

Gordon

Hi Gordon, Guys,

No there are no contact points in the needle head assembly ! The needle point is the contactor. It vibrates at the supply frequency, which in the UK is 50 Hz.

Anyway I've finished the drawing and added dimensions and notes. So it should be easy to build one, along with the pictures to help orientating the parts. I've called out all the threads as metric but I am almost certain that they are BA. 6 BA fits the brass strip to needle fastening and I would guess that the needle pinch screw is 8 BA, as is the screw that secures the head part in the plastic handle.

If anybody has any question, please feel free to ask me !

 

[BaronJ]

After spending a bunch of time looking at these tools, I wondered about making an electronically controlled version rather than an electromechanically controlled one.

Commercial products I found ranged from 500W to 2500W. This is a lot more than the 25W you have found in hour system.

25W is really easy to do with a MOSFET. 500W at 5 V is just a bit harder.

How important is the vibration of the tip? If the current were interrupted, could it work without the tip vibrating?

Carl

I suspect that the ability to generate a variable frequency supply, say from 50 to 200 or so Hz could be an advantage.

 

[Gordon]

Thank you. That is much appreciated. It now goes to the "to do" pile.

 

[petertha]

I have one of these Dremel's & it does the job. You can very the stroke. I'm not doing art, just ID-ing metal parts.

https://www.amazon.ca/Dremel-290-01-Stroke-Engraver-Template/dp/B0000302YN

 

[Gordon]

I have one of these Dremel's & it does the job. You can very the stroke. I'm not doing art, just ID-ing metal parts.

https://www.amazon.ca/Dremel-290-01-Stroke-Engraver-Template/dp/B0000302YN

Does it work on hardened tools like drills and reamers?

 

[petertha]

I actually haven't tried but I'm going to guess very light depth. I can certainly give it a go vs & take a closeup pic for you? I'm not sure which tip I have, according to website they offer a diamond too.
https://us.dremel.com/en_US/products/-/show-product/tools/290-engraver-kit
FWIW I've used a diamond ball tip, maybe 1mm diameter & 100 grit in a conventional rotary Dremel at high rpm which did mark on a hardened socket wrench tool. But it's kind of difficult to control, likes to skate around a bit probably because rotary motion. Even with engraver which is axial motion I usually trace over a fine tip felt line to keep me orientated.

 

[jack620]

I'm not one to sell tools (my kids can have that pleasure when I'm gone), but I've read that engraved tools attract lower sale prices. Some say up to 50% lower. So probably not a good idea to engrave expensive tools. Perhaps engraving the size doesn't devalue the tool as much as engraving your name. I engraved my name onto a Stanley plane once and immediately regretted it.

 

[ruzzie]

A article on builbing a Electromagnetic Etching Pen was published in Model Engineer Vol 171 No3952 September 1993

 

[HennieL]

Does anyone have a good way to mark tooling. I am talking about marking the size on small cutting tools like reamers etc. Things like the vibrating engravers will not mark hardened tools and a rotary engraver does not work well on small diameter tools like 1/8". Electrostatic engravers are too expensive for limited use.

Gordon,
You could consider the chemical etching technique that most knife makers use to etch their logos on to their knives (both hardened carbon and stainless steel). Just Google "photo resist etching"...
Here's an image of my knife-maker's logo:

And here's what it looks like on a knife:

and a wider view (on a different knife...)

This process involves the spraying on of a chemical "etch resist", the exposure of a "photo positive" (old film type positive made by either exposing an old-time film, or much easier just printing it on a transparent film using a photo copier), and then etching the metal with an acid or other etching chemical - I use ferric chloride. The very fine lines forming the fingers of this Bushman rock painting are perhaps 0.5mm thick (I suspect even thinner, but have never measured them), and as can be seen in the first photo they etch quite well, so making very fine markings will only be limited by the accuracy and clarity of the photo positive, with the photo-copying process giving not quite as good results. For less critical use (e.g. numbering of tools), one can eliminate the photo positive process, and just write on the clear film with a sharpie marker, or print a "negative" image on a laser printer with the number being left blank, and the surrounding area filled with black to create the number.

Hennie

 

[awake]

Gordon,
You could consider the chemical etching technique that most knife makers use to etch their logos on to their knives (both hardened carbon and stainless steel). Just Google "photo resist etching"...
Here's an image of my knife-maker's logo:

View attachment 126360
And here's what it looks like on a knife:
View attachment 126361

and a wider view (on a different knife...)
View attachment 126362

This process involves the spraying on of a chemical "etch resist", the exposure of a "photo positive" (old film type positive made by either exposing an old-time film, or much easier just printing it on a transparent film using a photo copier), and then etching the metal with an acid or other etching chemical - I use ferric chloride. The very fine lines forming the fingers of this Bushman rock painting are perhaps 0.5mm thick (I suspect even thinner, but have never measured them), and as can be seen in the first photo they etch quite well, so making very fine markings will only be limited by the accuracy and clarity of the photo positive, with the photo-copying process giving not quite as good results. For less critical use (e.g. numbering of tools), one can eliminate the photo positive process, and just write on the clear film with a sharpie marker, or print a "negative" image on a laser printer with the number being left blank, and the surrounding area filled with black to create the number.

Hennie

Beautiful work!

 

[HennieL]

Beautiful work!

Thanks. Unfortunately my photographic skills are not on par with my knife making

 

[awake]

Thanks. Unfortunately my photographic skills are not on par with my knife making

I don't know about that - the photo looked good to me!