Burs in the engraving.
- Thread starter Sandy
- Start date
fegarex
~ Elite 1000 Member ~
Sandy,
What kind of metal are you cutting? Things like nickel silver seem to do this. On steel it shouldn't be an issue however. I haven't really found a good way to eliminate it on soft metals other than polishing them off. Try adjusting the strokes per minute too.
What kind of metal are you cutting? Things like nickel silver seem to do this. On steel it shouldn't be an issue however. I haven't really found a good way to eliminate it on soft metals other than polishing them off. Try adjusting the strokes per minute too.
Hi Sandy,
What type of heel are you using?
What angle is the face and heel?
Is it just on tight turns?
And as Rex said, what metal?
What type of heel are you using?
What angle is the face and heel?
Is it just on tight turns?
And as Rex said, what metal?
It is one of the stainless steal key fobs from GRS. The face angle is 55 degrees with a 20 degree lift. The face is highly polished. I have also back releived the graver 2.5 degrees. I haven't polished the sides as much as the face.
Andrew Biggs
Moderator
Hi Sandy
I've come across 3 types of burr and this is my method of dealing with them.
1. The burr that occurs when you go around small scroll spines. Lift your elbow as you come around the bend. This raises the back of the graver and gives you a bit more clearance. Also angle/lean the graver to the outside of the cut slightly.
2. The burr that happens at the end of a cut..........drop the back of your graver and pop the chip out. Or dig the sucker out any way you can. Even knock it off with the side of the graver if nessasary
3. That tiny burr that can be seen on each side of the cut. It's very small and you can't even feel it, but when you ink your work it creates almost a double line. Well worn 600-800 grit backed up on a hard surface like a small stone or copper/brass will get rid of that. But only a couple of swipes as you don't want to round the cuts. If It's a shading cut I do the same but with well worn 1200-1500 grit. I normally use a bit of oil on the grit paper as well.
You may also be forcing the tool too fast through the work and not giving it enough time to cut properley. Try slowing down just a fraction.
I'd be really keen to see how other engravers deal with this as well.
Cheers
Andrew
I've come across 3 types of burr and this is my method of dealing with them.
1. The burr that occurs when you go around small scroll spines. Lift your elbow as you come around the bend. This raises the back of the graver and gives you a bit more clearance. Also angle/lean the graver to the outside of the cut slightly.
2. The burr that happens at the end of a cut..........drop the back of your graver and pop the chip out. Or dig the sucker out any way you can. Even knock it off with the side of the graver if nessasary
3. That tiny burr that can be seen on each side of the cut. It's very small and you can't even feel it, but when you ink your work it creates almost a double line. Well worn 600-800 grit backed up on a hard surface like a small stone or copper/brass will get rid of that. But only a couple of swipes as you don't want to round the cuts. If It's a shading cut I do the same but with well worn 1200-1500 grit. I normally use a bit of oil on the grit paper as well.
You may also be forcing the tool too fast through the work and not giving it enough time to cut properley. Try slowing down just a fraction.
I'd be really keen to see how other engravers deal with this as well.
Cheers
Andrew
fegarex
~ Elite 1000 Member ~
Sandy,
I'm at a loss to answer this one other than what Andrew mentioned.
I can say that sometimes those key fobs can be a bit "rubbery" and cause a little burr however. Sounds like the graver is fine. Sometimes it just happens. The only explanation I could have is that you are cocking the tool as it cuts if that makes any sense.
I'm at a loss to answer this one other than what Andrew mentioned.
I can say that sometimes those key fobs can be a bit "rubbery" and cause a little burr however. Sounds like the graver is fine. Sometimes it just happens. The only explanation I could have is that you are cocking the tool as it cuts if that makes any sense.
silverchip
~ Elite 1000 Member ~
While all of the above is good advice,it sounds like your heel is too long as well.don't forget to slightly polish the heel radii.I have found that these two things are critical in getting good results.
jerrywh
~ Elite 1000 Member ~
Might be the stainless steel or your heel could be too long or the graver might be dull. Try carbide if your not already doing it. Try that graver on regular steel. If it works OK then it is a good indication that it is the stainless.
Guys,
Thanks for all your help. I cut another one tonight and I was using an X7 graver highly polished face with a small universal heal. The bur is still there. I dont think that I am pushing to hard. If I can get a picture of the bur I will post it.
Thanks for all your help. I cut another one tonight and I was using an X7 graver highly polished face with a small universal heal. The bur is still there. I dont think that I am pushing to hard. If I can get a picture of the bur I will post it.
fegarex
~ Elite 1000 Member ~
Sandy,
Like Jerry said, try another type of metal to see if it is the stainless or not.
Are the burs in straight lines as well as curved?
Like Jerry said, try another type of metal to see if it is the stainless or not.
Are the burs in straight lines as well as curved?
fegarex
~ Elite 1000 Member ~
In any kind of metal?? Or just the stainless?
Christopher Malouf
~ Elite 1000 Member ~
Sandy,
Part of the problem with the burr on both sides of the cut is due to pushing (or displacing) the metal as you are cutting it.
An increased heel angle of 20 degrees will, in effect, increase the face angle with respect to the horizontal surface of the material being cut.
In essence, by holding the graver at a higher angle of 20 degrees as opposed to 15 degrees, it is like cutting with a steeper face.
You can either bring the face down to 50 degrees or bring the heel down to 15 degrees. By bringing the heel down, you are less likely to compromise the strength of the cutting tip. If breakage is an issue, you can also dub the tip.
That should reduce the amount of material that is raised on either side of the cut. Other than that, the only way to get rid of it altogether is to either sand back your work as Andrew suggests or make another pass to clean up the cut.
I suspect that those fobs are probably soft .... like annealed 410 stainless. As the graver cuts through soft and/or gooey metals (whether it is carbon steel, stainless or even gold), some material tends to get displaced . A good graver like the X7 or the Carbalt gives the best cuts especially when the face and heel is sharpened on the porcelain wheel and the face is angled appropriately for cutting rather than pushing/plowing.
Chris
Part of the problem with the burr on both sides of the cut is due to pushing (or displacing) the metal as you are cutting it.
An increased heel angle of 20 degrees will, in effect, increase the face angle with respect to the horizontal surface of the material being cut.
In essence, by holding the graver at a higher angle of 20 degrees as opposed to 15 degrees, it is like cutting with a steeper face.
You can either bring the face down to 50 degrees or bring the heel down to 15 degrees. By bringing the heel down, you are less likely to compromise the strength of the cutting tip. If breakage is an issue, you can also dub the tip.
That should reduce the amount of material that is raised on either side of the cut. Other than that, the only way to get rid of it altogether is to either sand back your work as Andrew suggests or make another pass to clean up the cut.
I suspect that those fobs are probably soft .... like annealed 410 stainless. As the graver cuts through soft and/or gooey metals (whether it is carbon steel, stainless or even gold), some material tends to get displaced . A good graver like the X7 or the Carbalt gives the best cuts especially when the face and heel is sharpened on the porcelain wheel and the face is angled appropriately for cutting rather than pushing/plowing.
Chris
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Rex, So far it is only in the key fobs.
Chris, I could be pushing on the graver but I don't think so. I keep an eye out for this. I'll give the 50 degree face a try and see what happens.
Kevin, I have been trying to get some pictures of the problem but so far I can get them to show the burs. The universal heal runs from tip to top on each side of the engraver.
Chris, I could be pushing on the graver but I don't think so. I keep an eye out for this. I'll give the 50 degree face a try and see what happens.
Kevin, I have been trying to get some pictures of the problem but so far I can get them to show the burs. The universal heal runs from tip to top on each side of the engraver.
fegarex
~ Elite 1000 Member ~
I think it is just the material.
The only other option might be to either really slow down the strokes per minute.
Or maybe even speed it up. Sometimes strange combinations work.
The only other option might be to either really slow down the strokes per minute.
Or maybe even speed it up. Sometimes strange combinations work.
Christopher Malouf
~ Elite 1000 Member ~
Hi Sandy,
I wasn't trying to imply that you were putting any unnecessary pushing force on the tool. It just happens and I notice that it is worse with steeper angle faces. Kinda like a snow plow. That little bit of raised metal on the sides of the cut bugs the crap out of me as well ... even though it is only really noticeable under the microscope. It's likely my tendency in trying to get all the material out of a deep cut in one pass. The second (and deeper) cut always cleans away those raised edges.
I do like it, however, when I use a flat to dig the trench for inlay. The tiny raised sides make it easier to scrape and lift away the excess gold before sanding or stoning.
Rex makes a great point about stroke speed too.
Have fun ... catch ya later, Chris
I wasn't trying to imply that you were putting any unnecessary pushing force on the tool. It just happens and I notice that it is worse with steeper angle faces. Kinda like a snow plow. That little bit of raised metal on the sides of the cut bugs the crap out of me as well ... even though it is only really noticeable under the microscope. It's likely my tendency in trying to get all the material out of a deep cut in one pass. The second (and deeper) cut always cleans away those raised edges.
I do like it, however, when I use a flat to dig the trench for inlay. The tiny raised sides make it easier to scrape and lift away the excess gold before sanding or stoning.
Rex makes a great point about stroke speed too.
Have fun ... catch ya later, Chris
Andrew Biggs
Moderator
Following on from what Chris has said about recutting the line to get rid of the burr........................sometimes it's just a matter of hand pushing it through the cut lightly and that will tidy up the cut a bit as well.
That "micro-burr" can be a real pain. When you ink the work it catches the ink and makes the cuts look wider. Generally I just hit it with really well worn grit paper with a bit of lubricant ..........spit works well
Cheers
Andrew
That "micro-burr" can be a real pain. When you ink the work it catches the ink and makes the cuts look wider. Generally I just hit it with really well worn grit paper with a bit of lubricant ..........spit works well
Cheers
Andrew
d.soileau
Member
ive noticed a burr when cutting too deep with a standard heel. i havent had much of that problem with a polished parallel heel.
that and i try not to cut so deep.
that and i try not to cut so deep.
Sandy,
I'm not sure what you mean by the "top edges".
If you mean a cut line with puckered edges to the cut, I would ask you if you are stropping the tool? If you are, there is one other reason for displaced metal rather than sheared metal. Again if you are stropping the tool, this sometimes creates a narrower leading edge to the belly facet, than the trailing edge. This creates a wedge effect and rather than cutting the metal, it pushes it up along the edges of the cut. Is that what you are talking about?
There is nothing wrong with stropping the tool, but you must be carful not to take more off of that crisp cutting edge than you do off of the trailing edge of the facet. It doesn't take much to get that wedging effect. By hand you would notice the difference by the amount of force that you would have to use to make a cut. With a power tool you would never notice it as the sensativity of the touch is not developed to detect it.
One other thing is, if you are cutting deeper than the length of the lift facets, you will drag the tool around the curve and the keel of the tool will tear up the outside edge of the cut. Leaning the tool toward the outside of the arc or curve will help this a bit.
Other than that, I don't know what to tell you without being able to see it.
What is the width of your point? 90, 120, or what? A narrow tool will also be rougher on the edges of your cut and should only be used for very shallow lines i.e. shading and/or hairlines. The 90 is a finnesse tool.
Ron S
I'm not sure what you mean by the "top edges".
If you mean a cut line with puckered edges to the cut, I would ask you if you are stropping the tool? If you are, there is one other reason for displaced metal rather than sheared metal. Again if you are stropping the tool, this sometimes creates a narrower leading edge to the belly facet, than the trailing edge. This creates a wedge effect and rather than cutting the metal, it pushes it up along the edges of the cut. Is that what you are talking about?
There is nothing wrong with stropping the tool, but you must be carful not to take more off of that crisp cutting edge than you do off of the trailing edge of the facet. It doesn't take much to get that wedging effect. By hand you would notice the difference by the amount of force that you would have to use to make a cut. With a power tool you would never notice it as the sensativity of the touch is not developed to detect it.
One other thing is, if you are cutting deeper than the length of the lift facets, you will drag the tool around the curve and the keel of the tool will tear up the outside edge of the cut. Leaning the tool toward the outside of the arc or curve will help this a bit.
Other than that, I don't know what to tell you without being able to see it.
What is the width of your point? 90, 120, or what? A narrow tool will also be rougher on the edges of your cut and should only be used for very shallow lines i.e. shading and/or hairlines. The 90 is a finnesse tool.
Ron S
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