Share your tips, hollow grinding straight razor?

M

matthewhoffman

Joined
Nov 19, 2016
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Hello all,

I'm hoping some of the razor makers might chime in. I'm in the early stages of filling a junk bucket with wrecked straight razors. I'd love to get some general advice on how the experienced makers approach their free-hand hollow grinding.

More specifically: I'm using 3/16 52100 ... the blades are about midway between 6/8-7/8 in width ...and I'm using an 8-inch wheel and finishing with gator belts (220-600 grits). I'm having a heck of a time walking the grind down toward the spine without chewing up the edge (particularly the middle part of the blade) in the process.

Maybe I'm just in the expensive part of the learning curve. But if anyone can save me some steel (and thumb skin), I'd love all the insights I can get.

- matthew
 
Are you using the workrest? Maybe try laying the blade on its spine on the workrest and using a finger to push the bevel into the wheel? I havnt yet done hollow grind but have seen others do this trick. some making straight razors..
 
I haven't tried the work-rest approach yet. I prefer working freehand when I can, but maybe that's not ideal for a beginner. I've been watching videos showing freehand (from Lewis Razors). Boy, he makes it look easy!
 
People say that HG is the easiest. My first experience was difficult as it kept "grabbing" and not grinding smoothly.
In the end I found free hand easiest and coarser grits are easier. I still need to be careful to get it to stay smooth with the highest grits.
I would get the entire grind done first at the lowest grit (36 or 60) before moving up.
I too have an 8" wheel, but I would say that it is much too large for a razor. Those are usually tight radius wheels such as 3" or smaller.
 
I'll be curious what folks have to say about the 8-inch wheel. From my reading, it should be good for a 1/4 hollow on a 6/8 blade--but maybe I've got that wrong. I do have a 4-inch wheel that I could take for a whirl.
 
I found the same issue grinding wharncliffe blades with the middle getting removed faster than the sides. I've found clearly marking my scribe lines and going slowly, being cautious to keep even pressure against the whole blade helped me. I hope it helps you too
 
Use the work rest. I don’t know why people limit/hobble themselves. Like it’s some weird kind of bragging rights to make something with limited tools. “I made my knife with nothing but a stone wheel powered by my feet!” We use 2x72 grinders, heat treat ovens, and every other technological advancement, but when it comes to grinding a blade there’s a weird ego thing wrapped up with grinding “free hand.” People need to really get over it and just use the method that allows them to consistently, and efficiently turn out quality work. Whether that happens to be with a Tool rest, jig, or free hand, doesn’t matter. What matters is the end result.

I like to rest the spine of a knife on the Tool rest and tilt the blade into the wheel where I want it to be ground. Then I just pull it across the belt while pushing it into the belt with my other hand.
 
Here’s a video of Travis Wuertz doing a hollow grind. I think this technique would be ideal for razors.

 
I've done quite a few of these. I always use the work rest. The shape and size of a razor make it easy to grind, the thinness of the grind makes it difficult. There are different types of hollow grinds, 1/4 hollow, 1/2 hollow, 3/4 hollow and full hollow. It depends on how much of the flattish area is from the edge to the spine. A full hollow looks like a "T" shape in cross section. Smaller wheels and blending towards the edge is required to do a full hollow. Using a 6 inch wheel will produce a 1/4 hollow grind. It's important to scribe the center line and grind to that. The edge needs to measure .005 after finishing. Multiple devin razors.jpg

Hoss

*edit
Some makers will hone before finishing the grind to reveal areas that are uneven. I find this particularly helpful.
 
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Hoss, your razors are an inspiration! Stunning work. Much thanks for the insights. Looks like it's time to practice on the work rest, and with a 6-inch wheel. Look forward to giving it a try.
 
I have split 2 inch wide belts in half and had them track on one side of the wheel or the other. I found that width of belt easier to use for razors with the initial coarse grit belts.
 
For a Wharnie like on a straight razor I would make it easy and use a jig like a dd work rest and grinding jig
 
Your tool rest is part of your Grinder. Utilize your tools!! Don't listen to those who knock it! There are no bonus prizes because you freehanded a blade. Keep us updated.
 
I know it's been a while since anyone posted.
The reason people will find the middle of the blade is ground down faster is because it tends to spend more time against the belt, as well as flexes. If you think about how we pull the blade across the belt, you'll realize that the heel of the blade (closest to the handle) is "pulled" past and off the belt first, leaving the middle and toe of the blade still in contact and still being ground away. So then, why isn't the toe of the blade the most ground down? Because straight razors are usually about 3 inches long. Most of us start grinding with the heel on the belt, pull across and bring the heel off the belt, while now the toe is starting to come on the belt and be ground. All the while though, the middle blade is in contact the whole time.
It takes a lot of experience to get this down. I recommend trying to not pull the blade across the whole way. Instead, start with the heel and middle blade on the belt for 1 or 2 seconds, keeping it still. Then lift straight off. Now, whatever part of the blade at the toe that wasn't in contact, put just that in contact. Do this as you approach Apex. In my opinion, you shouldn't "finish" your blade on the belt. Once you reach Apex go to your stones. Just my method. It won't work for everyone. That's why there are so many ways to do this--none of them are perfect in all hands! So find your best way. And share it. You'll for sure be helping others to be better.
 
i do mostly 7/8 and 8/8 razors and use 10 5 and 2 inch wheels depending on how hollow they need to be. i free hand but no shame in using a rest work heel and to more then you think thy need (th emiddle of the blade tends to be where you burn through) i liek to mock sharpen to find the places that the edge and spine hit on theb stone then grind again to make the hone marks even
 
I've only made two straight razors so I'm not an expert in any means but I used a workrest while grinding both of them and have gotten pretty good results.
 
D DevinT Hoss, I'm inspired to try making some straight razors out of 1/4" W2.
Is it crazy to think about profiling it last? It seems that it might be easier to grind using the work rest if I'm still dealing with a rectangle especially the handle.
Also, I imagine grinding to a scribed line, edge up. With a 2-1/2" wheel, would you also do the blending edge up?
Thanks!
 
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