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Making Rotary Burnishing Tools

Making Your Own Rotary Burnishing Tools

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Making your own rotary burnishing tools

Rotary Burnishing Tools are used in various metalsmithing applications to smooth out and cover up porosity holes in metal.

These burnishing tools are used and form part of the Making Fused Jewelry Tutorial which is an in depth technical tutorial consisting of 47 pages and over 80 pictures, showing three different projects and various methods of setting stones in fused metal and fused component manufacture.

This free tutorial follows the same format as all my other free and premium tutorials. This gives you a good insight into the technical teaching methodology

Making burnishing tool from 3mm ball fraser

I start with an old 3 mm ball frazer for this one.

Shaping burnishing tool on grinder

I rough shape it on a bench grinder, just to get most of the teeth off.

smooth shaping out of burnishing tool

Once it is rough shaped it needs to be smoothed out a bit more.

polish burnishing tip with sandpaper

I sand the ball tip further with a 220 and 1200 grit buff stick whilst it is spinning in my hanging motor.

Heat up burnishing tool to bend

Once the ball is smoothed out to 1200 grit, I bend it to just under 90ยบ using my torch.

I use my steel block and then heat the tip cherry red.

Heat on burnishing tool

It looks hotter than it really is, and also it doesn't heat the steel block at all.

Bend burnishing tool with soft pressure

With soft pressure and as the tip heats up it bends slowly.

Best angle for burnishing tool

This is the angle that I have found to be the easiest to use.

Fix burnishers after heating

Looks terrible, but it's easy to fix up.

remove fire scale from burnisher

I use a 1200 grit sanding mandrel to remove the fire scale, which isn't very thick.

polish tip of burnishing tool

And then I use a normal polishing buff on my polishing motor to shine it up.

Four burnishing tools mostly used in workshop

These are the four different rotary burnishers that I use most often.

Generally spoken, burrs are made of high speed steel. These are heat hardened and then tempered for general use.

When the burr is shaped and bent, the temper is removed, effectively making the metal softer.

With the next shape I make I will also show how to restore the hardness to a burnisher.

Make burnishing tool with another shape

With this shape there is a little more work to do to obtain the desired shape.

First I rough shape it on the bench grinder.

Heat tip to shape burnisher

This time I first heat the front of the burr bright orange and then allow it to air cool.

This will bring the metal to a hardness that will allow it to be filed with a normal file.

Burnishing tool with flat sides and rounded corners

Then I file two flat sides on it and gently round all the corners with 220 and 1200 grit sand paper.

Then I polish it on my polishing machine.

Now, as with the round tip burnisher above and the three sided burnisher, they have to be re hardened.

For sure one could use them as they are, because the high speed steel is harder than gold or silver. So if they were to get marred, all that has to be done is to polish them up again.

Heat burnisher to bright yellow and cool in oil

But it is just better to make them hard again.

An egg cup filled with engine oil is all that is needed.

The burnisher is heated to bright yellow like in the picture.

It smokes when burnisher is quenched

Then it is quenched in the oil until it is cooled down.

Burnisher tip covered in scale

The tip is covered in scale when it comes out of the oil.

It is easily removed with your 1200 grit buff stick and then polished on the polishing motor..

Burnisher flat-sided polished shape ready for use

Finished, hardened and ready for use.

Burnishing tool with soft corners

I made sure all the corners have soft curves.

Three sided burnisher shape

This one was also made from a 6 mm ball frazer and ground into a three sided shape on the bench grinder.

Then it was also finished with buff sticks and polished on a polishing motor.

It is then hardened as well.

This shape is handy for getting in narrow spaces.

pointed shape of three sided burnisher

This is the basic shape, and you can imagine that were it spinning very fast, it would move the metal forward quite nicely.

By moving metal forward, I mean moving it forward to close any holes and pits that make up porosity.

Example of commercially available burnisher

This is a commercially made burnisher. They are costly and they are big and clumsy.

I seldom use them.

Close up of commercial burnisher

A close up showing the smoothed out burnishing head.

Jewelry before using burnisher

Here is a before and after comparison of some 14 kt gold with quite a lot of porosity .

I used the round tip rotary burnisher here.

Porisuty smoothed out with round tip burnisher

As can be seen, there is a substantial improvement.

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