Question: Graver Sharpening for Bulino

[dbrodhagen]

Hi all, I know how to sharpen the 80 degree graver for Bulino work, my question is with the 105 degree graver. First off, while watching Christian DeCamillis's he says that he perfers the 105 and I thought that I would also give it a try. He mentioned he gave the graver a 45 degree face, while the 80 degree is 55 degrees. Would the post still remain at 12 degrees and the angle at 50 degrees or would the angle be changed? Thanks in advance for your help.
Dave

 

[silverchip]

I believe that the face angle would not change much but the lift on the tool (or post)would remain the same.the only thing to change are the yaw angles =52 1/2 on each side of the bottom.
I lent my dvd to friend and can't confirm the facts just now,hope my bad memory doesn't get me in trouble here.

 

[dbrodhagen]

Silverchip, I think that you are right, it makes sense that 52 1/2 on each side would equal the 105 degrees, and it would seem that anything less than 12 degrees would be somewhat steep for the lift. If anyone else thinks differently let me know, these gravers are kind of expensive. Thanks, David

 

[Andrew Biggs]

52.5 on each side will give you a 75 degree graver.

The way to work it out is.................

180 degrees minus the angle that you want your graver to be. Then divide that by 2.

So for a 120 graver it would be............

180 - 120 = 60 divided by 2 = 30 degrees each side

A 110 graver would be............

180 - 110 = 70 divided by 2 = 35 each side

A 105 graver would be..........

180 - 105 = 75 divided by 2 = 37.5 degrees each side.

The face is only to ad strength to the tool. an 80 degree graver needs more strength to the tip so therefor a steeper face is required.

A wider tool like the 105 is already very strong and you may be able to use a 45 degree face........but it depends entirley on the metal that you are cutting on.

The lift to the tool provides clearance for your hand and to keep the tool off the work. Depending on the surface you may need a higher lift.

Higher/lower lift and face angles..........These are just variables that depend very much on the surface you are working on.

Cheers
Andrew

 

[dbrodhagen]

Andrew, all I can say is Wow, thanks for taking the time to explain the way an angle is determined. I have copied it for quick reference. The help that everyone gives in this forum is invaluable, I hope someday to be able to reciprocate.
Thanks,
David

 

[Andrew Biggs]

No worries, glad to help out.

Maths wasn't exactly my strong point at school but once you start getting your head around it....... it's a peice of cake.

Cheers
Andrew

 

[silverchip]

Thanks for the correction Andrew,my perception of that tool is based in backwoods geometry :big grin:.

 

[ETHELBERT]

yep, leave it to a signartist & you'll likely get a correct answer. Very well explained Andrew