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Making a Pneumatic Graver / Air Engraver


Wildfowler
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Hi OF,

The Damascus will be another project, and will certainly not be engraved, I'd let the pattern of the steel do all the work there...

Having never made it, I'd need to do a fair amount of research to get the pattern right for the shape of the action or side plates, it's not going to be any time soon unfortunately!

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  • 2 months later...

I spent some time yesterday finishing it off (the wood isn't very good but its all i have about at the moment, i'll replace it when i get some walnut for my gun stock)

attachicon.gifIMG_3362.JPG

attachicon.gifIMG_3364.JPG

And this is it testing the pedal (i'll make the actual pedal this week) and making the first few cuts. Seems to work ok?!?

I would like to know if you have any blue prints available

thank you

Richard

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Hello there...

I've been contacted by quite a few people now asking for a set of plans for this.

 

I designed and built the graver to prove the concept to myself and play with different materials to see what impact it made on the performance, whilst learning to engrave at the same time.

Whilst I do think the most well known pneumatic gravers are over priced, I don't wish to compromise someone's business or livelihood by selling or distributing a set of plans for an alternative product. The top manufacturers can charge a premium because they have invested in the development of their product. As I don't have any plans to develop my version at the moment, until I'm in a situation to do so, unfortunately the graver and the plans will remain in a drawer.

 

If anyone is truly intent on making one, the physics of how it works are really very simple. Spend half an hour with a piece of paper, a pencil (& a rubber,) and in my case a calculator! and get your grey matter working! It a simple case of pressure differentials, ratio of surface areas for pressure to act upon and the most simple form of self operating valve...

The best way to do it, is try it!

 

I know this may seem self righteous to some, but I really don't wish to devalue a fellow engineers product.

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Fantastic project, I've wanted to learn how to engrave for a while now, it's always something I've had in the back of my head, and I've also thought of making a pneumatic engraver, I think it's great you've just gone for it! Have you ground the gravers yourself too? What's your sharpening set up?

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Hello there...

I've been contacted by quite a few people now asking for a set of plans for this.

 

I designed and built the graver to prove the concept to myself and play with different materials to see what impact it made on the performance, whilst learning to engrave at the same time.

Whilst I do think the most well known pneumatic gravers are over priced, I don't wish to compromise someone's business or livelihood by selling or distributing a set of plans for an alternative product. The top manufacturers can charge a premium because they have invested in the development of their product. As I don't have any plans to develop my version at the moment, until I'm in a situation to do so, unfortunately the graver and the plans will remain in a drawer.

 

If anyone is truly intent on making one, the physics of how it works are really very simple. Spend half an hour with a piece of paper, a pencil (& a rubber,) and in my case a calculator! and get your grey matter working! It a simple case of pressure differentials, ratio of surface areas for pressure to act upon and the most simple form of self operating valve...

The best way to do it, is try it!

 

I know this may seem self righteous to some, but I really don't wish to devalue a fellow engineers product.

just wondering why you use a foot control and not a o ring in the piston ?

Edited by richardwest
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  • 6 years later...

i am astounded at the chunks of metal you can cut out with that...........you could never ever push that deep...and you would need a serious hammer (if you could controlit)  to cut smoothly at that depth.......

nice on ...i like that ..:good:

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  • 4 months later...

I am designing an air powered graver following a similar concept. I believe that your graver is a copy of the Lindsay Airgraver as the patent is on line and youtube has many submissions of the Airgraver design.

I am working on a variant design that doesn't use the constriction Ring.  My Piston is barbell shaped, the ends 3/8" dia. and a center section 1/4" diameter x 1/4" long. A cross hole is drilled thru the center section and mates with a hole drilled from the bottom to intersect with the cross hole. The tube housing vent holes are 1/4" from the Air in connector.

The barbell piston has more mass, thus it hits harder than the airgraver style piston. The piston is supported by two weak springs to locate the center section, centered at the Air In  fitting. 

My design runs strong but needs more work to greatly reduce air consumption. It isn't practical to have a compressor running continuously. So far, air usage is a factor of: air leaks around the piston; b, excessive overlap where the piston power stroke is complete but the air can continue to enter the graver.  

The piston forward motion is initiated by the air flowing into the small center diameter and exiting thru the holes into the rear of the piston. The air pressure not drives the piston forward to contact the Graver Mounting. As the piston goes forward, the side of the rear part of the piston  blocks off the incoming air. Now, the piston center is positioned over the air out vent holes. The air that was driving the piston forward is now exhausted. The piston strikes the end of the graver mounting and now bounces back to the original position to start the cycle over.

My initial design graver starts at 10# and screams at 60# air pressure with 40# pressure about right for work.

My plan is to run the air line from the compressor into a large water trap filter. From the filter run the air thru a bypass at 15# to keep the graver oscillating but not contacting the cutter. The main air line will pass thru a high pressure regulator at 40#, thru a Foot Petal air switch to the graver.

Fitting the Piston and cylinder: Drill out the cylinder thru the main housing tube. The surface will be rough. Reaning won't greatly improve the finish. Single point lathe boring will improve the finish, make the hole constant diameter, but it is still too rough. Make an expanding lap out of steel and solder copper sheeting over the steel core. Charge the copper with valve grinding compound and then push the lap back and forth to remove the roughness from boring.

With the ID smooth and consistent, turn the piston until it can be forcibly enter the tube ID. Use Wet/Dry sandpaper 220 grit and sand the piston until it will freely slide in the tube ID with almost zero clearance.  Now the piston is virtually air sealed against air leakage.

The bottom line (goal) is the graver should use very little air, yet have all the power that is needed to engrave the work piece. When get my design worked out I will gladly share it with anyone. I believe the Barbell shaped piston design doesn't copy any existing graver patent or any system currently marketed or shown on youtube. It basically is a takeoff of centuries old Steam Engine Valving Design.

Please comment on this posting. I just joined this forum.

 

 

 

 

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