I'm realizing now that my Gold Dollar P80 has a bad bevel angle due to an overly thick spine. So I want to thin the spine down, but I want to keep the sides even so my bevel angle is consistent on both sides of the edge. Is there a good method to ensure that I'm removing an even amount of material on both sides, or does it really matter too much as long as it's close?
Thining the Spine of a Gold Dollar
- Thread starter dabrock
- Start date
You can do all the thinning only on one side and the bevel angle will be the same. The bevel width will be different but not the angle
rbscebu
Girls call me Makaluod
How to:
- Measure the current blade and calculate the current bevel angle.
- Decide on the new bevel angle that you desire.
- Calculate the now required spine thickness to achieve your desired new bevel angle.
- Tape the edge.
- Lap the spine on your preferred hone using the same number of laps per side.
- Measure the spine thickness every so often while lapping.
- Stop lapping when you achieve the required new spine thickness.
- Remove the tape from the edge.
- Reset the blade's bevel and progress as normal.
- Thread starter
- #4
That's good to hear, I'm just trying to keep it even now by sight.
I ended up having to shave nearly a full millimeter off so I ended up using a belt sander because lapping on even a 60 grit paper was taking forever! I do have a bit of an even line now on the spine so I'm grabbing a 120 Shapton stone tomorrow from Lee Valley to even it up.
It's a lot lighter now lol.
Thanks for this. I had forgotten all of my trig, so I went looking. I'm not sure whether it's OK to link what I found, might be a competitive site, but the formula seems to be:
2 * arctan(x / (y*2))
Where x is the thickness of the razor at the top of the honing guide (aka its thickest point), and y is the vertical measurement from the top of the honing guide to the edge, except it's not the edge, it's a vertical plumb line down from the top of the honing guide to the surface on which the edge rests (that's conceptual, I didn't actually touch the edge to anything).
That yields radians, so multiply by 57.29578 to get degrees (for the included angle).
That led me to:
Titan HRC 70: 16.6 included angle, 8.3 bevel angle (that's probably a touch more acute than stock; I spent a small time with pressure on the honing guide)
Iwasaki kamisori: 13 included angle, 6.5 bevel angle
Which explains why the Titan angle felt too obtuse for my preferences.
In Excel terms, the inclusive angle in degrees is:
DEGREES(2*ATAN(X/(Y*2)))
rbscebu
Girls call me Makaluod
Most of my SR's are in the late 16's degrees for bevel angle with some a little over 17°. My new Revisor 6-0035 appears to be closer to 15° although I don't have the gear with me to accurately measure it.
Being use to me previouse SR's, it is going to take me a few shaves to get use to the Revisor's bevel angle. That is why I am going to spend this week shaving exclusively with the Revisor.
I think that a lot of a shaver's preferred bevel angle is determined by what he gets use too.
Being use to me previouse SR's, it is going to take me a few shaves to get use to the Revisor's bevel angle. That is why I am going to spend this week shaving exclusively with the Revisor.
I think that a lot of a shaver's preferred bevel angle is determined by what he gets use too.
- Thread starter
- #7
That's what I had put in my spreadsheet too. We never realized in high school how useful trig was lol.
- Thread starter
- #8
That's probably true. I can imagine a 15-degree angle feels harsher than a 17-degree angle and probably requires a different angle to the skin.
- Thread starter
- #9
I think the edge is now shave-ready so tomorrow I will test it. I was able to get a pretty quick stiction on my Impiria finisher so I was happy to see that since I understand that's supposed to be a good sign.
I don't know how often I'll be able to use the 120 stone I got today but it really did even up the spine pretty fast.
I don't know how often I'll be able to use the 120 stone I got today but it really did even up the spine pretty fast.
Different angle to the skin, maybe. It's an instinctive adjustment, so hard to say. Harsher, no. I have come to believe that harshness in SR shaving is a function of an edge that is either ragged at microscopic level, or simply not keen enough.
You don't need a 120 stone, until you need it badly.
- Thread starter
- #12
Certainly, those microscopic nicks and warps also cause DE blades to dull so I can see that.
Fortunately, there's a Lee Valley near my house!
- Thread starter
- #13
Well, finally figuring out the geometric issues. The spine wasn't just too thick but it also had a consistent thinning towards the toe so the heel wasn't getting sharp and it was difficult to hone enough to be shave-ready. I flattened one side and tomorrow I'll work on the side that's worse. I think I'll take a Dremel to it for a few seconds to take down the heel a bit faster because all of this honing is rather tiring lol.
At least I can finally see a light at the end of the tunnel and this razor really was a great teacher for honing, because it wasn't very well made.
At least I can finally see a light at the end of the tunnel and this razor really was a great teacher for honing, because it wasn't very well made.
Keeping the 'hone wear' band an even width on each side should keep the center of the razor centered.
It's true that taking all the material off of one side would result in the same bevel angle, but then the bevels would not be aligned with the grind of the hollows resulting in either a wider bevel on one side than the other, or a bevel pushed off center with asymmetrical hollows.
I once thinned a GD spine by using a bench grinder and repeatedly running the blade with a taped edge over a coarse stone to show me where the high spots were. When I got close, I finished the job on the stone. Now I would use my surface grinder attachment on my belt grinder.
It's true that taking all the material off of one side would result in the same bevel angle, but then the bevels would not be aligned with the grind of the hollows resulting in either a wider bevel on one side than the other, or a bevel pushed off center with asymmetrical hollows.
I once thinned a GD spine by using a bench grinder and repeatedly running the blade with a taped edge over a coarse stone to show me where the high spots were. When I got close, I finished the job on the stone. Now I would use my surface grinder attachment on my belt grinder.
- Thread starter
- #15
Sounds like a good idea, of course, I don't think I'll be buying GD after I'm done with the few I purchased, I just don't like them lol.
Yeah, I don't bother working on them anymore. If I'm going to do that much work on a razor I'd much rather start with my own blanks and heat treat.
Though, if you look at them as buying a heat treated blank they're a pretty good deal for people who don't have the means to get to that stage on their own.
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WHAT?!?!!?! LOL
I like my razors for different reasons, but my GD66 and GM666 definitely have a permanent spot in my case.
GD now unrecognizable to the layperson, GM only just made to shave. Still "original"
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- #18
I know some really like modifying them, I'm just not that ambitious lol.
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- #19
I finally slew this little bugbear that I had given up on for a little while. I decided to continue working on the 120 stone then worked a lot on the 1200 DMT to get the geometry corrected to the point that it would sharpen to an even edge. I originally put a Corti edge on it a couple of days ago, but the shave yesterday just wasn't what I wanted with a lot of issues cutting hair evenly. I put it back on the 12K and realized that I had a few trouble areas so went back to the 1200 DMT and worked backup, but decided to go the 16K and 30K Shapton Glass route instead of the Corti.
Today's shave was really smooth and sharp, even took a small nick as if the blade was telling me it's no slouch. I'm happy that I finally got this to the shave ready state I've been looking for, but now I wonder why people seem to think GD doesn't hold a sharp edge. It's clear that it's not as hard and won't last as long, but it certainly is holding the 30K edge well, and is as sharp as my professionally sharpened Dovos and TIs I recently purchased.
I'm not saying I'm going hole hog on GD, but I will certainly keep them in my rotation and use them to play with different finishers.
Today's shave was really smooth and sharp, even took a small nick as if the blade was telling me it's no slouch. I'm happy that I finally got this to the shave ready state I've been looking for, but now I wonder why people seem to think GD doesn't hold a sharp edge. It's clear that it's not as hard and won't last as long, but it certainly is holding the 30K edge well, and is as sharp as my professionally sharpened Dovos and TIs I recently purchased.
I'm not saying I'm going hole hog on GD, but I will certainly keep them in my rotation and use them to play with different finishers.
If you have the skill and patience, a well prepared Gold Dollar can hold it's own with razors costing many times more than what you paid for it. I have a few in rotation that has been through a diamond pasted balsa progression that equates to 200k grid. No problem, and because I strop it on the balsa after every shave, I never have an issue with edge retention.
