Tuesday, September 8, 2015

Making a Rotary Burnisher

 

 


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.

making rotary burnishing tools burr

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

making rotary burnishing tools shaping

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

making rotary burnishing tools forming

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

making rotary burnishing tools sanding

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

I have a free tutorial Making Buff Sticks on my Jewelry Making Classpage.

making rotary burnishing tools flame

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

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

making rotary burnishing tools bending

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

making rotary burnishing tools heat

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

making rotary burnishing tools angles

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

making rotary burnishing tools close up

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

making rotary burnishing tools 1200 sanding

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

making rotary burnishing tools polished

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

making rotary burnishing tools shapes

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.

making rotary burnishing tools shapes flat

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.

making rotary burnishing tools shapes flame

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.

making rotary burnishing tools shapes flat sides

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

The I polish it on my polishing machine.

Now, as with the burnishers in Image No. 11 and this one and the one in Image No. 21, 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.

making rotary burnishing tools harden burr

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.

making rotary burnishing tools oil cooling

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

making rotary burnishing tools flat 1200

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.

making rotary burnishing tools finished

Finished, hardened and ready for use.

making rotary burnishing tools round edges

I made sure all the corners have soft curves.

making rotary burnishing tools pointed

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.

making rotary burnishing tools magnified point

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.

making rotary burnishing tools suppliers

This is a commercially made burnisher. They are costly.

I price them at $34 to $100.

They are big and clumsy.

I seldom use them.

making rotary-burnishing tools suppliers close up

A close up showing the smoothed out burnishing head.

making rotary burnishing tools before burnishing

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

I used the rotary burnisher in Image No. 11.

making rotary burnishing tools after burnishing

As can be seen, there is a substantial improvement.

This free burnishing tutorial is a part of my
Making Fused Jewelry Tutorial which is an in depth technique 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.

All premium Tutorials follow the exact same format as seen in this free PDF downloadable - Making of Rotary Burnishing Tools

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