Re-cutting a 'High Speed Steel' bur. (19 photos)

 When your all important cutting bur is no longer doing what it's supposed to do, are you going to throw it away? The answer is a definite NO! 

 In this tutorial essay, I'll show you how to repair it in only a few minutes.

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 In this first photo are the only tools that are used to repair these "High Speed Steel" burs. I use only a 'Separating Disk' of a "Medium" grit. This wheel is 7/8" of an inch in diameter, why so little? I know that if it was any larger, I wouldn't have the opportunity in seeing what is needed to repair.

 You don't need to recut all of the teeth from the bur-shaft to the outer rim. Totally a waste of time!

 You should only recut (as shown in this photo) where the tooth cutting process is touching your precious metal.

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 Additional photos of HSS burs from my own personal inventory.

 This HSS bur is too small to repair, just one cut with your Separating Disk will damage the teeth beyond repair. PLEASE DON'T ATTEMPT IT.

 You can see up close all of the edges of the teeth are 'rounded' and not being able to cut into any metal. This bur is a good candidate for fixing.

 

 There is a limit on the size of burs to repair. I'd stay with the larger size, please!

 

 Large Round burs are made of softer "Carbide Steel" and not the HSS that we all use in cutting bearings in gold for Engagement rings.

 If I didn't 'mark' the edges of any bur, I wouldn't know which tooth I started on. This is my idea as they would all 'sort of blend together' in the cutting processes.

 

  This bur is on the verge of needing to be repaired. Every cutting tooth "MUST BE AS SHARP AS A RAZOR".

 

 In the background are smaller burs that are really 'dull and worn'. The decision to have these repaired is up to you..(I wouldn't do it, as they are damaged beyond repair). Plus the many teeth are too close together for the Separating disk.

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 In this photo is a bur that has the outside teeth damaged by continually touching hard metal. These teeth are now unable to cut the simplest metal namely, gold or silver. 

 In a close-up photo, you can now see just how the broken teeth are just unable to do any metal cutting.

  You can now observe where the rotating "Separating Disk" touched the HSS bur. Don't dig into the bur teeth, all you must do is to allow the disk to gently 'recut the bur' steel.

 The cutting should be at the upper and lower teeth, why here? That is only where the 'tooth cutting' is taking place.

 This photo shows at 200x magnification that these damaged and very badly broken teeth. They are  just useless bits of steel. "Accuracy in cutting", is important for your 'Engagement' rings.

These teeth must now be repaired, instead of discarding this expensive bur.

 Do not attempt to cut anywhere else than what you are seeing in this photo. The chances of re-cutting many times will slowly reduce the overall size of the bur. 

=> For your added information, I 'darken' the bur with an ink-pen as I need to know exactly which tooth I'm working on. 

 This 'set of burs' are in my tool inventory and you can see the large 'repaired bur' and the area where the teeth were repaired.

 Your selection of HSS burs can be very expensive, any repairing is always needed. A full set of HSS burs can run into many, many hundreds of dollars, I know this for a fact.

 I hope you learned much from this tutorial essay.

Gerry Lewy.