Graver drift problems

[DaveatWeirs]

I've had this weird effect happen the past few days where, as I'm cutting, my graver drifts slightly side to side. It's kind of like a car losing grip driving uphill in snow, the graver is still cutting and moving forward but shifting sideways off the cutting line.
So far it has happened to me when engraving a silver dish and just now on the steel case of a bulova so I don't think it has to do with the hardness of the metal. I'm using a Lindsay Airgraver with carbolt inserts if that counts for anything.

Anyone else come across this?

 

[tdelewis]

First check the heel to see if it is even on both sides and parallel to the edge of the face. Keep the piece flat and don't let it tip to one side while cutting and looking through the scope. I myself have tipped the work piece over while looking through the scope, and not realized what I have done. I have learned to guard against it by looking at the work regularly without the scope.

 

[Sam]

If sharpening is accurate and symmetrical, then there's nothing I'm aware of that would cause a graver to drift. I'm assuming it's pilot error.

 

[allan621]

Sam's right. If the tool is properly sharpened and you are on the line cutting it can't drift off.

Just make sure your tool is properly sharpened. If you have a scope check the point. Even if you put the point into a fingernail and it catches check the point anyway. If there is a tiny aberration in point it may cause the point to lose the line and veer off slightly.

Sometimes if you are going slightly deeper than you should you end up trying to cut through a small mass of metal instead of cutting on the line. This may cause your tool to slightly veer and trying to correct this and go back to the correct spot can be a real problem.

If you are using any air powered tool is to make sure you are not turning the block faster than the tool is cutting. If you are cutting any kind of hollowware its kind of easy to not realize when the piece is at an angle. Like anything else, if this is new to you it takes a little to get used to.

So if everything is looking like it should then make sure the point is on the line and then focus only on cutting the line. If you are thinking of anything else and you attention is not focused on the line then the tool gets to decide which direction to go in; which is usually not the best idea.
Allan

 

[JJ Roberts]

When I started engraving with H&C the ongolett was my go to graver an I had a drift problem when engraving borders it was the heel the heel needs to be even on both sides. J.J.

 

[monk]

make sure the retaining set screws are properly tightened. if not, that could possibly contribute to the drift. check the heels under the scope. as others said, that's likely the cause.

 

[DaveatWeirs]

Thanks so much for all the advice everyone.
After checking everything that everyone had said I was still having the same effect occasionally on the watchcase, only tiny tiny shifts to the left or right as I cut until I was cutting a capital E (about 2.5mm tall). The line at the top pulled upwards away from the middle (relative to how you look at it on a screen), the line at the bottom pulled down and then when I was cutting the middle line it almost stopped dead and I had to ramp up the power to cut it.
I think there's, for want of a better word, 'grains' of variable hardness in the metal that's pushing the graver to the sides. I wouldn't surprise me with the dish if it was work hardened in weird ways as it was antique and fairly battered plus I was doing big ol' deep cuts but the variability in a watchcase surprised me. I haven't cut that brand before so I don't know if it's common with them but it was really weird either way

 

[FANCYGUN]

this might sound stupid but... check to make sue your graver is properly set into the holder. If it's not centered and that could also be the cause of your drifting. Make sure it is going straight out

 

[mtlctr]

Far be it from me but…..I’ve found an uneven heal only veers of one way right or left depending on which way the heel is off. Good luck.
Kent

 

[papart1]

they're tricky little skudders

 

[rweigel]

Happened to me when the graver‘s point (120° carbide) lost an all so tiny chip on one side. Visible only under the microscope. Even the tumb nail test still worked. After sharpening it cut straight again.

Cheers

Ralf

 

[mtlctr]

they're tricky little skudders

Like a sailboat with a bent skeg

 

[monk]

not an attempt at being rude, but your problem could simply be graver control. how much time have you spent doing simple practice plates ?

 

[allan621]

Thanks so much for all the advice everyone.
After checking everything that everyone had said I was still having the same effect occasionally on the watchcase, only tiny tiny shifts to the left or right as I cut until I was cutting a capital E (about 2.5mm tall). The line at the top pulled upwards away from the middle (relative to how you look at it on a screen), the line at the bottom pulled down and then when I was cutting the middle line it almost stopped dead and I had to ramp up the power to cut it.
I think there's, for want of a better word, 'grains' of variable hardness in the metal that's pushing the graver to the sides. I wouldn't surprise me with the dish if it was work hardened in weird ways as it was antique and fairly battered plus I was doing big ol' deep cuts but the variability in a watchcase surprised me. I haven't cut that brand before so I don't know if it's common with them but it was really weird either way

Grains of variable hardness it could be. We think of metal as a uniform solid but it actually has a granular structure. A grain is a lattice of atoms.

The grains align themselves into a larger crystalline structure. The grains are separated by a grain boundary which is like a wall between rooms. What make a metal strong is the grains uniformly aligned. When the grains are misaligned the metal is weak. The dislocation of the grain boundaries is what causes metal to give way and break.

Its like you have a graver that works well for weeks and then needs resharpening after every cut for a few cuts and then goes back to maintain sharpness for another long while. What happens is that you come to a place in the grain structure where the grains are misaligned creating a weak spot .

All this means is that the watch case metal you are trying to cut is probably a piece of s**t that someone manufactured as cheap as possible using whatever metal composition was the cheapest. In addition it probably has actual spaces in the metal called porosity. In that case its like trying to drive straight on a road filled with potholes.

If you are having trouble on the watch case take out a piece of copper and use the same tool on it without resharpening it. If it cuts well its the watch case. If it doesn't resharpen your tool and cut the copper first. If it cuts well on the copper but you have the same problem on the watch case, its the watch case. If neither cuts well... well its you. But I'm betting on the watch case.

My brain is getting tired.

Allan

 

[mtlctr]

Don’t trust atoms, they make up everything.