Engine Turning Surfacing Technique (Jewelling)

[br928]

The machining of overlapping circles or rings to create a decorative finish usually on metals.

I found some old posts on this subject not nothing recently.

Has anyone perfected this technique using the bot? I have ordered the engine turning kits from eastwood but I dont want to dress the rods every so many spins. As the rod wears down there is no way to automatically compensate to keep the pressure constant.

I am having some luck with a piece of ScotchBrite pad attached to the end of a dowell rod. I am getting a pattern but not a deep one. It's almost polishing the surface. Which is not a bad effect as it is. I might try adding some valve grinding compound to the oil and see if this will make the swirls deeper.

Does anyone know of a spring loaded attachment for a drill that would keep constant pressure on the surface independant of the Z position?
Has anyone made such an attachment?

This technique is very cool looking and a perfect application for the bot.



5196

[Brady Watson]

Try using an 1/8" shank SS cup brush @ 1/2" dia and some valve grinding compound. Worked well for me. The Craytex stuff is good for manual machines, unless you program in to compensate for wear.

-B

[drodda]

I used the Roloc scotch brite pads as they come in different grits and they are quick to change with a twist of the pad. the mandrel stays in the machine.

A couple of us were getting together on this to make a self learning program that would self compensate for the wear on the pad, However life and money making projects have clouded our ambition and we have not gotten around to it. We had produced two mandrels and were getting ready to test them. I think you could make a spring loaded mandrel pretty easy however the problem that I had with the scotch brite is it would load up with aluminum after about 100 swirls. For a small size piece this worked great.

This is one project that is near the top of my to-do list.

-D

[Brady Watson]

The Roloc discs do work well...but they are awfully big! Dave - have you found them in smaller sizes than 1.5 or 2" D?

-B

[br928]

Can you cut the Roloc discs down to the backing material diameter? What is that diameter? If a spring loaded mandrel can be made to keep the pressure constant then the problem is solved. By using tapping fluid (oil) on the surface of the aluminum the loading of the pad has not been an issue.

[Gary Campbell]

Stan...
Years ago I put that pattern on some tool steel using a drill press, a dowel and valve grinding compound. I put a straight edge on the drillpress table and then used strips of wood to make the overlap offsets, front to rear and side to side. The Bot would sure make that part easier.

I think you could do the same using either the pads or dowel in the SB drill, turn the air pressure down, and it would be self adjusting.
Gary

[drodda]

Yes you can cut the pads down to the size of the plastic backer piece. this makes them 1" and they woorked well at this size for what I was doing.
I only had a PC router so I could not slow the speed down enough to save the pad from getting filled with aluminum. I was working on a gear reduction to slow the router down to 2000 to 3000 rpm but once again I got sidetracked on trying to pay the house payment.

Keep me posted as the house seems to be paid up through the end of the year and I would love to get back on this project, Right after I build my new teardrop camper. Thanks to whomever it was that posted that thread in the project section, just what I need is a teardrop with a salt bath relaxation pool in it. The more I read the larger the to-do list gets.

-D

[br928]

Gary,

I am using a standard drill in my second Z so I can't use air pressure to control the surface pressure. Those that do have the air drill, that might work great.

Dave,

I started using my router but it just turns too fast. A drill motor is working better

These are some brackets machined on the ShopBot from 1/4" and 1/2" aluminum. This is a new CNC plasma table I am building.

The picture doesn't do it justice. I think I will get more comments about the surface finish that the CNC machine itself!



5197

[br928]

Here is a picture before it is assembled.


5198

[drodda]

Stan,

What size are your circles in the pictures? It is hard to determine the scale of these parts. I am thinking that I need an old non electronic router to test this on with a variable speed controller. This can't be used on the PC router though.

This looks good. I also bought the kit from eastwood but never found a use for it with the bot.

[br928]

Dave,

The plates are approx. 4" x 7" with 0.8" circles. I made 10 plates each with a different pattern.

Just find an old drill and strap it to you Z axis. Keep it simple!

I still think a spring loaded arbor is the answer. Surely some Botter out there has made one!

[Gary Campbell]

Stan...
I have a spring loaded clutch I bought from McFeely's. If you can find an arbor that has a 1/4" hex shaft.... $20 solution.
Gary

[smiller6912]

Here are some links to jeweling tools from BROWNELLS. I use these in my gunsmithing business and they work great.
http://www.brownells.com/aspx/NS/store/ProductDetail.aspx?p=606&title=ENGINE%20TURNING%20 BRUSH%20SET
http://www.brownells.com/aspx/NS/store/ProductDetail.aspx?p=607&title=E/T%20BRUSH%20HOLDER
http://www.brownells.com/aspx/NS/store/ProductDetail.aspx?p=609&title=ENGINE%20TURNING%20 KIT

[gene]

3M sells the rolock conditioning pads and accessories as well as metal polishing / dressing wheels

[drodda]

I was experimenting with a wire brush encapsulated in rubber. All was going well till I forgot to add the decimal in the Z plunge. The Bit tried to force the brush through the table and proceeded to melt the rubber and trash the brush before I could get to the stop button. Left a large burn mark under the metal on the spoil board also.

The idea was to have the rubber keep the brush from spreading out with the rpm and turning.

The actual look was more like a shiny polished swirl rather than the scratched swirl I got with the roloc pads.

[myxpykalix]

Dave,
You know the shopbot is funny like that...it will do exactly what you tell it to do, even if its wrong! Too bad we can't build in some failsafes that pop up and say "Are you sure you want to do that"? I guess if it could think for us it would be alot more expensive huh?
Don't worry dave you are in good company!