Introduction and Forging a Razor from a File

Hello SRP members, I'm a frequent poster on IFI, this is my first post on this forum. I've been blacksmithing for fun & profit for a year now, recently started turning old files into small paring knives. I had a customer ask me for a straight razor so searching on IFI led me to Bruno who provided more information than I imagined and suggested I join this forum. Thank you Bruno! As it will be relevant to know my setup for any of the following questions here's some of the tools I have. An 11" brake drum forge that I use blacksmith coke in (could use homemade charcoal if needed) 190lb Peter Wright anvil, 4.5" postvise, 5" bench grinder and a 1x30 Harbor Freight belt grinder.

A summary of the process I've used for the 3 files to knives I've completed was this, forge to shape, anneal overnight in ashes, profile and then rough grind until it's about the thickness of a dime ~.053, & drill holes for scales. Next for heat treating I normalize 2x, then heat to non-magnetic and quench in used motor oil. Then I bake in the kitchen oven at 450' for 1 hour, cool and then temper again using either the stove or propane torch til the spine and point are purple or even blue, and cutting edge a straw or brown. Then a finish grind to 1000 grit. To this point that's work well, I can hammer the point of the knife into wood and twist it out without it breaking and they've held a good edge, at least from what I can tell.

Attachment 135164Attachment 135165

Here are pictures of my current project, I've been trying to follow what was done in this thread by Grant, aka Baldy. What I'd like is feedback on the above process, I plan on using either vegetable or canola oil for the quench as I know the old motor oil isn't what's recommended. I don't know what is a recommended temper for razors.

http://straightrazorpalace.com/custo...ile-razor.html

At the same time I'm grinding the razors I'm also working two small knives, that way I can switch to another as one starts to warmup. I am concerned about the finish grind on the razors after the heat treat and when they start getting thin.

I was thinking the razors would be a flat grind only as that is what I have experience with.

Attachment 135167Attachment 135170Attachment 135171Attachment 135169Attachment 135172

Thank you for your time.

Dan Cravens
Central Texas

Hey Dan, good to see you here :)

Recommended temper for razors is a light straw color. 60 to 61 HRC is the sweet spot.
The spine needs to be the same hardness, because both the spine and the edge make contact with the hone, and you don't want the spine wearing out faster than the edge.

You need to do part of the grinding after heat treatment, because you want the blade near the edge to be as thin as possible, so that the bevels are as narrow as possible. Narrow bevels make the razor much easier to hone, and look much better as well.

This also means that when you are grinding after HT, you need to use sharp belts, run them at low speed, and regularly dunk the razors in cold water to prevent them from overheating. If the temperature gets too high, the temper is ruined for use as a razor. As soon as you see blue appearing near the edge, the razor is a dud. And sadly, the thinner you get, the more quickly the temperature rises.

Hi Bruno, very glad to be here & thank you for all the help in the past!!!

From the pictures can you tell about how the bevels are so far? How can you measure the angle?

I know what you say is correct, as from the small paring knives the thinner the bevels the sharper the knife. I've been debating this, but your response confirms holding off on a final grind until I can build a 2x72. The 1x30 belt grinder I have doesn't have a speed option. I also think the results would be more consistent, not to mention probably more efficient. I guess another question would be holding off on HT and maybe doing a hollow grind when the 2x72 is finished. Was thinking an 8" contact wheel?

8 inch is a good place to start. At least a little hollow grind is good - back to what Bruno said about a narrow bevel. If you have a full flat grind, you have to hone the whole side of the razor, and that would take forever. Good luck on your project. There is a wealth of info on this site.

Angle is simple: you know the with of the blade and the thickness of the spine.
You'll want to 'scoop out' some metal before HT, because hollowing out a piece of full hardened steel will be a lot more time consuming.You have about the correct thickness at the edge left for heat treatment.

Also when hollowing out, especially after heat treatment, the diameter of the hollow should be a little bigger than the hollow of the wheel. You rock the blade from spine to edge on the wheel a bit, if you know what I mean. The reason is that that will greatly slow down the heat buildup. If you have a hollow with the same diameter as the wheel, the entire hollow will make contact and the heat buildup will be very fast. I admit I ruined a razor this way. I was regrinding an old wedge, kept the blade cool, but as soon as the hollows became the same, the blade almost instantly flashed blue near the edge.

Btw, if you are still interested in having me look at them after the post HT grinding stage, PM me for address details. I'm traveling the next couple of days so don't worry if I don't answer rightaway.

If it is any help I did a file/razor a few weeks ago. It was posted in the "gallery". Also Baldy has just posted his latest razor which also was from a file too. You have done a nice job with yours. Keep up the good work and please keep posting your work for all to admire and to imitate. I would have never had tried a file if it wasn't for the posts that I have found on SRP. I am sure you will find a lot of support and knowledge at SRP.
OOPS! WELCOME my friend!! We hope to see more from you.
Ray

For the proper angle use the ratio method of blade width divided by spine thickness. The ratio should not exceed 4:1 . An example is a blade width of 1" should have a spine thickness of 1/4" or greater. This will result in an angle that will minimize the width of the bevel and make it easier to hone and have a stronger bevel that is less prone to micro-chipping at the higher grits. The historical ratios are 3.5:1 up to 4:1.

Hope this helps :)

Thank you Ray. It took me awhile to navigate the forum, but I found the thread with your razor from a file build. Very nicely done, I really like the photo showing the phone book and how you kept the old file name & logo! I will update my progress, but from the feedback I've gotten I am going to hold off on these razors until I have been able to buy or build a 2x72. I found a Bader Pro for sale at a reasonable price. If it's still available in a couple of weeks I should be able to get it. If not I'll build my own, there's a lot of good information out there on doing so.

Thanks Randy for the explanation on calculating the angle and the recommended ratios, that is very helpful. Everyone has been a great help so far. I'll keep y'all updated and take lots of pictures along the way, including the grinder build.

If you haven't already found it, USA Knifemakers in Minnesota has a kit and many individual parts for a no-weld 2x72. Go for some kind of variable speed control, either multiple pulleys, or, best, a phase converter speed control. If you want more info on phase converters, PM me.

I've been on the USA Knifemakers site quite a bit today and also downloaded the free grinder plans from SRP to make a KMG 3-speed clone. I would prefer to weld an all steel frame together, but should I be concerned about possible heat distortion to the frame and jacking the alignment? For that reason is it preferable to do a no-weld design? I'd be using a Lincoln Tombstone 220 arc as I don't have a MIG or TIG going w/ cold rolled steel. Could peen the welds and keep moving to minimize distortion.

Sorry, I'm sure this is covered somewhere multiple times in the forum.

The main area to be concerned about distortion is in the tube that the bar with the wheels on it slides into. When you weld it, put the bar into it, and add paper spacers. This will take care of the heat shrinkage issue. You may have to use an hydraulic press to remove the bar after welding. The Guild of Metalsmiths built around 20 of them several years ago, and I was involved in the welding. They were also a KMG clone. I have a KMG, which we used to redesign several areas. Again, PM if you need help.

Well the belt grinder has been put temporarily on hold as my truck's radiator had to be re-cored so I'm trying to finish any outstanding requests to pay for that and other parts the truck needs. The buyer of the razor had originally given the okay for a wedge so I proceeded to HT'ing after putting a slight upturn in the tang or handle. For both the razor and the knife in the picture there was a very slight curve after the 1st hardening (the razor's curve I think was from forging earlier) So back to the forge, straightened, normalized and hardened again. 2nd time around both appear to my eyes as straight as can be. Then I put them in the kitchen oven at 400' for 1 hr and they each came out a nice light straw color.

Now normally for a knife at this point I'd let it cool and then do a differential temper using the stove. I'll do that for the knife, but I believe a 2nd tempering cycle at 400 for 1 hour is what's recommended correct? I'll give each a very light sanding before doing either in order to observe the colors.

Attachment 136250Attachment 136251

I love how the brand and name of the old file stayed intact. I'm definitely hooked and plan on making a set of these for myself and then learning how to shave with one.

Two tempering cycles sounds good. I would not do any differential heat treating on the razor, unless you are wanting a temper line. I would try 400 and see how it acts on the hones and how the edge acts when shaving. If the edge is chippy are really hard hone I would up the temper temp by 25 degrees and so on. It takes a little bit of experimenting to get the process optimized for your tools in your shop.

Charlie

Thank you Charlie for the feedback and steps testing & tempering. No, I'm definitely not doing a differential temper on the razor. Only for the knife that's in the picture.

Without honing stones or personal experience using a str8 razor, I've taken this as far as I can. The person who asked me to make it has 1000, 4000 and 8000 stones along with a 12,000 hone, and is experienced honing his own razors so I was going to get with him to see if it meets his approval. After he finishes his part I'll post updated pictures.

Best I can tell the grind is even and edge is straight. As I worked it by hand with 220 grit, I would occasionally sand it perpendicular to the paper until the edge was straight and then go back sanding the wedge. Eventually it got to the point where I no longer had to do that as it was remaining straight and the drag across a moistened finger nail felt consistent.

Attachment 137403
Attachment 137402
Attachment 137401
Attachment 137404

Did he ask you to make a wedge whape? From the pics, it doesn't look hollow ground the slightest.
Honing and maintaining is going to be a real chore.

Yes, early on he had asked for a wedge and said he would hone it by putting tape on the spine. I'd been planning on building a 2x72 grinder in order to do a hollow grind, but that's on hold temporarily as my truck needed the radiator re-cored. After that I asked him if he'd rather wait or proceed with the wedge, he said to go ahead.

Your friend will need a microtome honing guide to hone that blade. It is essentially a tube with a slot cut in it lengthwise. That is slid over the spine of the blade and acts as a honing guide.
Tape would take far to many layers to be practical.

Hope this helps, :)

I will try to post some pics in a day or two.

Generally speaking, even wedges are hollow ground a bit, just for the sake of being able to hone it.
For this razor, the hone needs something that can be locked over the spine to lift it from the stone, or it will be impossible to hone. And it needs to lock very snug and be immovable, because if the spine has just a bit of freedom, it will not be possible to create nice flat bevels.

This link shows my microtome, the handle for it, and the honing guide that came from the mfg.

King Kongs Razor - a set on Flickr

Thanks Randy for the link and information, it's very helpful.

It's been slow going but my 2x72 build is coming along. I figured out how to get it to track properly and got from a co-worker a gas strut when he replaced the ones on his hatchback to use for the tension and tracking. Next up will be to mount the motor which came from a treadmill.

Attachment 168026

Quote:

---

Originally Posted by dcraven

It's been slow going but my 2x72 build is coming along. I figured out how to get it to track properly and got from a co-worker a gas strut when he replaced the ones on his hatchback to use for the tension and tracking. Next up will be to mount the motor which came from a treadmill.

Attachment 168026

---

Thanks for posting this, it gets the wheels turning.

And this may not be the thread for this, but has anyone used a ShopSmith as a power source/base for a grinding station?

Safe Grinding...

I had a treadmill motor on mine, for awhile. Never could figure out what parts controlled the speed, so I just mounted the whole works. Looked weird, but worked like a champ until the motor died. Now I've got a 3hp 3 phase, and a phase converter.http://straightrazorpalace.com/images/attach/jpg.gif

I'm so glad I stumbled upon this post. I've been looking for a custom hand made pairing knife for my wife for her birthday in a few months. Do you have an online shop?

Thank you for your interest. I just sent you a personal message.

Skipnord, when you were running the treadmill motor what size hp motor was it and what did you use for a pulley? I tested mine out last night, it's tracking well but gets easily bogged down. I used the pulley that was on the motor for the treadmill and ground down a groove using a file. It didn't seem to matter whether it was running at half or full speed using a 120 grit belt. From the picture it's hard to read the specs, it's a 1.75 hp 110 VAC 1305 WATTS.

I'm wondering if putting a pulley on the motor would help as I just filed down the pulley that was on there for the treadmill which is very small, or if I should start looking for an alternate source for motors.

I should mention I'm using an 8" contact wheel and a 4" drive wheel with a 3" pulley.

Attachment 168552Attachment 168553

It sounds like the belt is slipping on the motor pulley.

Just my 2¢

Thanks Randy. I figured it out when watching the video below. I noticed when at 2:10 he changes from the large lower wheel to the small lower and vice versa on the higher ones, thus slowing down the speed. That was exactly how mine was running so I cut a groove in the flywheel and made some changes above so it would run setup this way. Once I did this it began hogging metal.

Attachment 168598

https://www.youtube.com/watch?v=9OcbUTK5i5g

Good video. It sounds like you agree with Randy that your pulley was slipping. I put a regular pulley on my motor - about the same size as the driven pulley - and controlled the speed with the treadmill speed control. If you are just running the motor at one speed - hopefully its max, a set of 3 or 4 step pulleys will work to control your grinding speed. as I recall, my motor was a 2hp. Yours might be a tad weak - I'm using a 3hp now. Good luck with your project!

Actually no it wasn't slipping, I could see the motor itself coming to a stop vs. the grinder wheels stopping. That was when I was using the small step that I had cut into where the treadmill belt used to attach. So instead I ground a groove into the flywheel and then adjusted everything to run that way.

I apologize for the bad pictures, if they were larger and clearer I think it would be apparent what I mean. I plan on doing the same as you did skipnord in using the treadmill controls so that I have variable speed.

As I recall, I put the V pulley on the other end of the motor. I think you would be better off with a real pulley, than trying to use the flywheel with a groove cut in it. JMO. If you put a pulley on the other end of the motor, you will have to reverse the motor rotation, but that is just a matter of reversing the leads on the motor. The biggest problem with using a treadmill motor is that they are not "sealed". and metal dust can get into the guts and short them out. That is what finally happened to mine. Putting a piece of nylon stocking, or some similar fine mess over the openings in the motor may prolong things. Again, good luck.

Thanks. I figure this is a stop gap until I can get an enclosed motor.

I really like your grinder & your file blades. One concern to me is your base might need a little more mass. You might think of putting another upright as close to the front of the grinder as you can. I found in years as a blacksmith, welder & machinist that having the base of a tool be it an anvil, vice or what ever as solid as you can get it will make your job easier & more precise. Looks like you are going to put wheels on it, will you really have a need to move it? if not I wouldn't put wheels on it unless you have a good way to mount it to your shop floor.
Hey, it's all good. Great looking work. I am wanting to get a forge set back up with a 100Lb. Little Giant power hammer to forge blades & pattern welded stock. I have carpal tunnel & cubital tunnel problems so a power hammer is about my only way to get back into forging.

Dave "Slawman" Huffman