Homemade Engraving Machine

[Jeff2t]

If you have a lathe and a 3d printer you can make this ported piston power graver. The metal version works better, but the plastic one will be ok for getting into power graving until you can afford a professional set-up.
There's more stuff on my youtube channel that may be of use to the beginner.

 

[hdvoyager]

It has been a while since this design was made. From the operation diagram you have the information needed to make the graver. The graver needs the springs to maintain oscillations. My working model used a lot of air. The air usage problem was traced to problems with my 1952 vintage Logan lathe. namely, the ways ware worn to the point maintaining the necessary close tolerances can't be met. The lathe cuts a taper of .ooo5" per inch of travel.

The taper results in the bored tube as wall as the piston being slightly tapered. This is the source of the air leakage.

I have a 10" Logan vintage 1942 that uses 3C collets and does not have any wear problems. I plan on using this lathe to make the graver as soon as I get time.

Lessons learned:
Make a drawing of all the parts before cutting metal.

Make an accurate drawing of the piston's position for air in and air out, see theory of operation above. You can very the dimensions of the Barbell Piston to see how to make your piston and position the air in and pot ports. At no time can the air in and air out overlap!

The bore of the cylinder must be smooth and the sides parallel. Make the cylinder first and after the cylinder is finished, make the piston to fit. The piston must be free to oscillate in the cylinder but have an overall fit within 0.0005" or less to limit air usage. With the gap at 0.0005" or less, the air now becomes a lubricant as the air pressure will center the piston in the cylinder and prevent metal to metal contact.

You will need to play with the spring tension to get the piston to bounce or oscillate.

Tricks: The bore must be glass smooth. Drill and Ream makes an accurate diameter but the walls are still rough. The only way I have found to get the walls smooth is Boring at a very slow rate of feed. The cutting edge of the boring bit must be rounded, not pointed. Lapping compound may help with a brass lap. Make sure to remove all lapping compound. Use a rounded Small Hole Gage to make sure the sides are all the same diameter, full length.

Drill the air In/out holes and burnish any burr out. If the holes are drilled before the boring step, the result will be a slight grove will be cut on the circumference adjacent to the holes which is bad.

So far, to fit the piston, the piston should almost fit in the finished cylinder. Take 600 grit wet dry 3M sandpaper, wet, and polish the piston walls to a high shine to a point where the piston will enter the bore freely but there isn't any measurable side movement in the piston when pushed sideways.

To repeat, the key to getting operation is piston/cylinder fit and make sure that here isn't any air in to air out overlap.

 

[Winstonklein]

Save the challenge. Why would anyone bother with building an Air graver. any reputable hand piece on the market will do until your retirement. Get the skills instead and go chase the money. Life is too short.
My talk is addressed to any would be Engraver or stone setter. not a machinist . my 2 cents

 

[Jeff2t]

Save the challenge. Why would anyone bother with building an Air graver. any reputable hand piece on the market will do until your retirement. Get the skills instead and go chase the money. Life is too short.
My talk is addressed to any would be Engraver or stone setter. not a machinist . my 2 cents

In my case it was a combination of the challenge, lack of funds for the professional tools ( I made 4 air gravers for under $100) and occupying myself during lockdown, Some people watched Netflix, I got in the shed and did stuff.

 

[SlamDunK]

Pretty special learning on a tool you made yourself too. I did the same.

 

[hdvoyager]

If you are a good machinist and have the equipment necessary to do the job, building your engraving equipment is a source of great personal satisfaction. If you value your time, making your own engraver can possibly wind up being more expensive than buying an established companies equipment. In my case after making several gravers over a period of several months, I found that the old Logan 11" lathe was lacking in the necessary precision to build a great air powered graver. My gravers worked but my compressor worked over time to compensate for the air leakage in the graver.

My suggestion is to FIRST take a basic class in the art of engraving. There are classes offered in different parts of the USA. At the class, they will have all the necessary equipment. Then after the class has concluded you can make a well informed decision of what equipment you will need.

I do woodturning. I designed and built a Ball Turning System, Thread cutting tool for machining male and female threads two start threads, an Articulated Turning Head Hollowing system, and my latest project, is an Oval Chuck. I take great satisfaction in using these tools, including giving talks and demonstrations at wood turning clubs.

I also do Blacksmithing. I built my side Blast Forge and Super Sucker Hood. Pounding a piece of steel into a useful item is very satisfying.

As you see, making tooling is a challenge in its self. Then using the tools to make items of great beauty becomes a new challenge. Buying good tooling from commercial sources will greatly speed up your learning curve process for making the end item.

 

[Doctorslava]

There are several points regarding self made engraving setup I want to mention. I started my journey several years ago without much ambitions. I just wanted to engrave as a process and not as occupation. If you take engraving as a hobby - it is an expensive hobby and my budget did not allow paying several grands for an equipment. But I have enough machining skills and tools and I thought I can make the machine myself. And I did it spending around $150 on materials. Now after 2-3 years since I finished my machine and started using it I may give some advises to those who thinking about building their own. Forst of all what is your goal? If you want to make engraving your living source take the class either from GRS or just from a master engraver. You can build a machine that will reciprocate and will look like a real one, but without knowledge what exactly it should do you may be disappointed in handmade machine performance. Unfortunately I had nobody to ask that time and just learned slowly myself and iteration after iteration I improved my machine. And after several years of such a learning I understood that I am ready to invest in the high end engraving device more than a $1000 and now I am using a handle designed by engraver and built by engraver. And it is important. Regarding the compressor for a Waltman type device: not all compressors are capable of continuous work so I recommend a compressor with a carbon rings, not with a plastic or a rubber diaphragm. Heat treatment of the tube and the piston are important too as well as the mass of the piston. and of course you should be able to regulate a stroke and a power. I think it might help to other people to make a decision. Slava