some over-unders have that jeweling finish on the sides of the breech end of the barrel assembly. I recently had a Beretta where that was scuffed up and it would have looked better to have that dressed up. Some of the model 12's had the exposed side of the bolt dressed up that way.
I'm not sure how to do it but am thinking it might be done with a coarse ink or pencil eraser in a drill press and an x-y table. Just an idea. Any suggestions would be appreciated. Thanks! Gil
I've experimented with jeweling on some scrap metal. I used rubber, like an eraser, in a drill press, with some rubbing compound for an abrasive. The rubbing compound was 1500 grit and didn't work very well. I think a coarser grit would have been better.
A "softer" material of rod shape carries abrasive while turned/rotated against a "harder" polished surface. So, a "rubber" rod works well as the "softer" material, adrill press is good for powering the rotation, and oil base abrasives do well as the "scratcher" material. The scratch circles must be overlapped in both directions. An X-Y table will make for very even spacing of the "swirls." Too fine an abrasive and the scratches are too small to see, too course and they don't look good. The level of polish also plays a role.
Cratex abrasive rods work reasonably well. There is considerable range of grit so you can experiment with the polish, metal hardness, and grit.
DDA
Way back in the 60's, we did parts with an ink eraser in a drill press or a mill. The quality of erasers has probably changed since then.
What's this "eraser?" Is that like a backspace or delete key?
I guess you guys cannot use the word 'rubber'
Last time I used a piece of aluminium round bar as the applicator and 'chemico' valve grinding paste as the abrasive
Try using a piece of wooden dowel or turned to size nylon rod to carry the abrasive.
Personally, I prefer highly polished surfaces to jeweling.
I guess you guys cannot use the word 'rubber'
Last time I used a piece of aluminium round bar as the applicator and 'chemico' valve grinding paste as the abrasive
In these parts a rubber is a condom and I don't think a condom would work very well for jeweling.
Getting back to the topic I think an eraser would conform better to a round surface like a rifle bolt.
As Rocketman mentioned earlier, a rubber Cratex abrasive is a very simple and effective way to go. It isn't messy like using wood dowels or aluminum rods, etc., with oil based abrasives (Clover compound). You can see what you're doing much easier.
I've done it with a leather disc affixed to a dowel held in a drill press. An X-Y table is needed to get the precise overlapping.
Did the leather work gnomon? I've even thought of cutting out small disks of 400 wet/dry and use a cohesive to stick them to a dowel rod.
Too much work JRB.
If you haven't used a Cratex to do it, you're doing it the messy and hard way. They are easily cut with a knife or saw and dressed with a grinding wheel dressing stick quickly to shape or size.
One caveat. Depending on what kind of abraisive you use and if you are using a drill press, it is easy to over do it and make gouges where you just wanted those swirling patterns. At least, my drill press makes it somewhat hard to monitor the down pressure.
Brownell's sells or used to sell small round steel wire brushes with a stem to fit a drill or mill to jewel with. Worked best with a drill press with a fixture to hold the piece being jeweled.
The wire brushes provide a better finish on round surfaces. A piece of heat shrink tubing will prevent the brush from flaring to much and still allow the brush to conform to the shape.Cratex rods work well on flat surfaces.
Did the leather work gnomon? I've even thought of cutting out small disks of 400 wet/dry and use a cohesive to stick them to a dowel rod.
Works very well. I think this is the classic technique. The leather acts as a lap and holds the abrasive.
You'll need to do a few test runs so that each pattern is the same intensity but that is a relatively easy skill.
I've used abrasives and brushes, and prefer the brushes. It is very important to have some way to index the piece uniformly as the work progresses. Trying to eyeball is is a recipe for really ugly results.
Methods aside, engine turning that is done on parts that rub (e.g. the bolt in a M12 pump or the sides of the breech block on an O/U are predestined to show signs of wear or even obliteration. You can re-jewel, but it's going to happen all over again. I prefer to do it right the first time and then let tthe normal wear accumulate as a sign of a gun I enjoy using.