Heel drag issues

[jkaragias]

I am currently suffering from some serious heel drag issues. At first I thought it was operator error. I used a graver (120 square) a teacher had made for me which has a parallel heel (made from a Lindsay template I believe) which gave me no issues and I was able to perform decent cuts with no drag. I have a GRS D/A fixture and machine and have watched Sam's video on sharpening. I've tried to replicate what's shown in the video to the best of my ability. Some gravers I make with a GRS style heel (<.25mm) tend to give me issues with drag. I also am using about a 17 degree heel. I'm not entirely sure if I am still making the gravers incorrectly or if there is another trick to sharpening them that I am missing. It very well may be operator error but the fact that I can execute these cuts much better with the aforementioned graver confuses me a little. Any help is appreciated and for the record I am a novice so any additional input would be great
Thanks !

 

[JJ Roberts]

Your problem may be the parallel heel it has to be even on both side. J.J.

 

[BCan]

JJ's correct, and for my two-cents worth: don't forget about how much a little oil of wintergreen or other lube on the tip or your graver, helps.

 

[jkaragias]

Your problem may be the parallel heel it has to be even on both side. J.J.

I am currently using a traditional heel on them. the ones that seem to work a little bit better have a higher heel angle and are just done on a 1200 grit disc. When I make a heel with the ceramic lap (no power), I have trouble with the heel drag. Even though the heels are the same size as the ones I'm making with a 1200 grit disc.

 

[rweigel]

I recently discovered that too short a heel causes problems with heel drag. I agree this sounds paradoxical. The same graver geometry (face/heel/V angle) I have to hold over the workpiece at a lower angle to achieve a constant cutting depth when the heel is very short, and at a steeper angle when the heel is longer. So I got a handheld microscope with a graduated scale in the optical path to measure the heels while sharpening, and produced for the first time heels with the recommended width of about 0.25mm. To my eye, this looks about twice as wide compeared to what I used before. As the graver now has to be held steeper, it causes less heel drag in tight corners. I‘m currently practising flare cutting in mild steel, most of my actual engraving I do in Silver, where the issue never arrose. Probably the hardness of the metal to cut plays a role as well. My gravers are made from ultra fine grain carbidur, point breakages disappeared since I use 0.25mm heels. Face 55°, heel 17.5°, V angle 120°, V shape ground with 2.5° from the graver axis. I shaped one graver with 120° parallel to the axis, it cuts not different from the others.

Cheers

Ralf

 

[jkaragias]

I recently discovered that too short a heel causes problems with heel drag. I agree this sounds paradoxical. The same graver geometry (face/heel/V angle) I have to hold over the workpiece at a lower angle to achieve a constant cutting depth when the heel is very short, and at a steeper angle when the heel is longer. So I got a handheld microscope with a graduated scale in the optical path to measure the heels while sharpening, and produced for the first time heels with the recommended width of about 0.25mm. To my eye, this looks about twice as wide compeared to what I used before. As the graver now has to be held steeper, it causes less heel drag in tight corners. I‘m currently practising flare cutting in mild steel, most of my actual engraving I do in Silver, where the issue never arrose. Probably the hardness of the metal to cut plays a role as well. My gravers are made from ultra fine grain carbidur, point breakages disappeared since I use 0.25mm heels. Face 55°, heel 17.5°, V angle 120°, V shape ground with 2.5° from the graver axis. I shaped one graver with 120° parallel to the axis, it cuts not different from the others.

Cheers

Ralf

I did notice that the closer i got to .25mm, the easier it is for me to make these cuts. Ive had trouble with too long of a heel and too short of one as well. Does it matter if i make the heel with a 1200 wheel versus a ceramic lap? using the same method of course..? Also, just the actual angle of your heel effects the cutting angle correct? or does the length of the heel play a role in that too?
Sorry for all the questions im very new to this and i like getting an understanding of how all the angles work and why i would choose one over the other.
Thank you

 

[AllenClapp]

You said that you are using the traditional heel, which is a short triangle. Unless you have a long heel, the triangle is small and the heel does not go very far up the sides. If you cut deeper than the heel, you end up with an issue. I suggest that you change to a parallel heel, where the heel runs all the way up the sides and see if that doen't cure the problem.

 

[JJ Roberts]

I think maybe the other problem in the graver drag is the relief angle. J.J.

 

[ByrnBucks]

Good evening Jkaragias, I believe one of the first great hurtles is getting a consistently sharpened graver that works well for the individual. Im wondering if the DA fixture your using is throwing you for a loop as the options are almost endless. I hope I’m not overstepping posting this “If I am please forgive me” but I believe it may help.

Try using these angles to on a fresh blank and see how it works for you.
45* face = set your DA graver dial to 0* and 45* on fixture angle
120* shape = set Graver dial to 30* and 2.5 on fixture angle Then move to the opposite side and repeat 30* and 2.5, taking care to make these two as even as possible so your point is center.
15* parallel heel = set DA dial to 35* and fixture angle to 15* and just try one swipe on 1200 disk no power.

Don’t put so much worry into measuring the heel, start with one swipe and give it a test drive, experiment try two swipes, then three once you find the one that works good for you and then go with that no need to measure your heal time and time again.

Here’s a picture that may help clarify how your dial can be much less overwhelming.
Hope this helps and you have a wonderful day. BB

 

[DocsEngraving]

Don't disagree with the previous comments, though I can't say I've seen heel drag often with short-heel... more often than not, it's a long-heel issue. BUT - here's a possible pearl for you, which I learned from Rex Pederson: Keep your elbow UP! If your elbow gets too lazy/ too low - it can exacerbate a heel drag. Just something to try out. Either that will help you, or it won't.
Best of luck!
Doc

 

[AllenClapp]

There is another question open right now relating to parallel heels. I just posted info on making them for any face angle, vee angle, and heel angle in that thread, so take a look there.