Okay, I'm trying to shorten the learning curve here. I've spent a few hours getting the feel of my tools and decided that old sawblades are unusable...they are way too hard to cut and grind! The damn thing was chipping the teeth off a bimetal hacksaw blade, and they sting when hitting my arm! So I picked up some assorted barstock...and started with a section of 1095 (cause it's cheap!) Now the questions:

Is there a 'rule of thumb' on how thick the blade needs to be when it is XXX long? I have 1.5" wide, 1/8" thick 1095 barstock. I sketched out a full tang blade, and it ended up 11" long and just looks like it might need thicker metal to hold up.

Is a 4" handle enough? That would leave me 6-7" of blade, less if I get sloppy around the tip. My sketch showing a 5" handle looks better, but when I hold a cardboard cutout, the handle looks too big.

A handle should be 4-5" long [measure your hand]. Typically a 4-5" blade should have about a 1/8" thickness depending on use.For 6-7" I'd go for 5/32 - 3/16".

I love 5/32 for everything

I am now working some 3/16 and it is ok but it is to think for little knifes IMHO.

You should anneal the saw blades before working them.. I would tell you how but I would probably screw it up..

Blade thickness will depend on design and length.

With blade edge lengths of 3 1/4" or less I often use 1/8". For mid range blades, say 3 1/2" to 6" or so I most often use 3/16, and larger I use 1/4" with a distal taper.

Of course, for kitchen knives these thicknesses and lengths are not appropriate. 3/32" can be used for most blades up to 7 or so inches. Very long slicers usually have to be thicker simply because it is so hard to grind a very thin knife that long.

As to handle length, measure the width of your palm at the beginning of your fingers. Can range from 3" to 4 or more. The part of the handle that touches your hand underneath should be at least this long.

Then adjust the balance of the design (blade length, ricasso width, blade height, and handle length including the guard area).

It can help to make a wood model of the knife to see how it feels.

Balance is adjusted by the taper of the tang and the number of holes drilled under the scales. It should balance just in front of your hand ... in the guard area.

Take a look at the Engnath site to see his designs. His proportions were very good and his drawings roughly to scale.

Do you guys use a jig to get the edges of your blades square? I have the basic shaped roughed out and am trying to square/true up the spine and grip area. First the belt (80 grit Norton, the blue Norzon+ IIRC) on my grinder wants to bow out at the edges...so getting the back flat is proving hard, and then I can't get a good square back that I am happy with. Am I getting too worried too early?

First, saw blades are hardened and should not be cut with a band saw. Saw blades need to be cut with a torch. I grind freehand with no fixtures. Spend time practicing grinding steel that hasn't been heat treated. 0-1 is easy to grind and a good steel to start with to build experience in the subtleties of the grinding art. It's all in "feel" while grinding. I have a Bader 2 1/2 horse grinder I bought in 1981 that I've gotten to know well. Practice. I made lots of mistakes grinding when I started. That's how I learned.
Don

DMB - I was thinking aboput tring a stock-removal to make a spear head. I was thing about tring to make this from automotive leaf spring.

Your thoughts???

Boss,
A car spring will work just fine for a spear head. There will be a lot of work involved to get it looking like you want it. But, that same problem exists no matter what steel you use, hardened, or not. Don't know what kind of grinder you have, or have accesss to, but I'd take off the excess steel with a 60 grit belt, dipping frequently to keep the temper in the steel. When you get close to the final shape you want, go to 80 grit, then 120, 220, and 320. From there, I would work by hand for the final finishing due to the spear head shape. Work slowly and check your progress often as you can't put back on steel that you took off. And, you want to have it look good without removing too much steel, more than you want.
A spear head sounds like a neat project.
If you run into any questions, don't hesitate to ask.
Take care,
Don

Don - Thank you!...I thought that would be a good choice. I can get a few for free too.

I thought I'd have a local welding shop rough out my design, plasma cutter?? Then as you suggest, work from rough grit down to fine. I hope to be able to have a few blanks cut-up for the enevitable, "ooopps", that is boundto happen.

My goal is a 8-9" long by 3" wide elongated diamond with a 20" tang. I thought the sring steel would be a good choice due to it's ablity to flex. Also the thickness with give the spine of the head and tang strenght.

OCS (Old Chevy Spring) is most often something similar to 5160. If you start with a real car spring of about 1/4" thickness, it must be straightened to provide the initial working stock. To get it really straight it'll have to be heated to a temperature that will wipe out its existing heat treating.

Hammer it staight while it is hot. Best to take it just beyond the critical point (to non-magnetic), and then let it cool inside a good insulator like dry fresh ash or vermiculite. This annealed material will be easier to grind.

After shaping and rough grinding, you can heat treat it again by going just over the critical point, and quenching it in 75% ATF/25% 10 weight motor oil. Take it to just under the critical point and quench it again. Take it to a slightly cooler state and quench it again. This is called grain refining and will result in a much finer crystal structure in the material.

Then heat it above the critical point one more time and full quench it.

Do the fine finish and the heat it in the oven at 400 to 450F for 3 one hour passes. This will probably get you to about RC 55 or so ... which is hard, but not too brittle. With salt we like to go to NO harder than RC 55 for large items. For Spear points RC 50 is really OK.

Read Engnath's discussion of finishing.

The technique used for grinding very much depends on what kind of grinder you have. I taper tangs on a disk grinder, but do all of my other work on a 2x72" belt grinder. Both grinders have DC variable motors.

When I do the knife blanks, I use a rest on the grinder after carefully setting it so that I'll be making a square edge on the billet. I do not have a rest on the disk grinder.

The edge of the material making first contact with the disk will cut the fastest if everything else is equal. I control the pressure on the blade by the amount of twist that is applied. That is, I tend to put a little more pressure on the trailing edge of the material if I want a flat surface. You have to move the material across the abrasive surface as well, because the inner part of the abrasive is traveling slower than the outer edge.

There is some practice required here ... so don't be too surprised if it isn't all that satisfying the first time.

Good luck with the project.

I gave up on the sawblades and got a 3' piece of (supposedly) annealed 1095. Dang stuff will still knock off teeth from bi-metal hacksaw blades if you press down too hard! Hot bit's o' metal!

I got the basic shape done...but hand filing the nooks and crannies is probably going to have to be 'good enough' for now. Now to shape the handles and guard...

Do you start with 'pre fab' finger guards, or cut your own from brass barstock?

I still can't figure out why my belt is trying to curl away from the platen at the edges...??? It was new when I started this one blade!

You can certainly buy a pre-slotted guard and then fit it ... just takes a little file work.

I have a full sized milling machine with a very high quality DRO and therefore make my own. Often from Nickle Silver or Naval Bronze rather than brass.

Thought you were using a disk grinder. If that is the case, I have found that the reason disks pull away from the edges of the platten is that there is not sufficient glue under them. I clean the platten, spin it up slowly, and spray 3M contact cement on the platten. I then spray the back of the disk, wait until it's tacky, and plant it on the platten.

I use disks that are about an inch larger than the platten and them cut them when they are mounted.

If you are using a belt grinder, I suspect you may be overlapping the edges too much during use and thus stretching the edge of the belt. I use the tracking adjustment to put a specific amount of belt beyond the edge ... and repeat that adjustment ever time I switch sides of the belt. I also use a piece of scrap steel to breakup the edges of the belt just a bit when I change to a new one ... so I can feather the plunge. Otherwise, the edge of the belt will cut too rapidly.

quote:

Thought you were using a disk grinder

Gotta (relatively) cheap combo unit, 4x36 belt and 6" disk...really a woodworking unit, but it seems to be doing pretty well so far. I'm getting all of a half hour a night at it, but no problems thus far....with the grinder.

Now if I could get the feel of holding a consistant angle on the primary edge grind...and starting it at the same point every pass!

I need to drill my holes for pins too...any 'rules' for quantity/size/position? I've studied about a dozen similar knives on various websites, and some use 3, most use 2, and sizes appear to usually be 3/16-1/4". Spacing seems pretty well 'evenly spaced' for strength to my mechanical mind. They will be solid brass pins, cut from rods as required...and it is a fixed blade clip point, full tang, 4.5" handle, 11" overall length (so far...might get shortened).

I use 1/4 inch stainless tubing, cheap easy to come buy and looks decent. For a lot more money you can use the mosaic tubing which is 10x better looking..

If you are taking about pinning the guard, use at least two ... and leave plenty of room to the edge of the ricasso so that you are not creating a weak place for a crack to start.

For the handle, use whatever spacing looks balanced. I use two for most knives and three for larger ones ... up to a 1 1/2 hand hold.

You can use cutler's rivets, Loveless screws (stainless screw with brass or bronze ends, solid pin, or mosaic pins. I like mosaic pins but they are not inexpensive ($25 a foot) even if you make them.

The blade grinding comes with practice ... lots of practice. Sounds like things are coming right along. Keep at it.

OKay, guard is fitted...with a few tiny gaps...blade is shaped and smoothed to 320 grit finish...primary grind is resonably uniform (as good as it's gonna get)...handle is drilled with 2x1/4" holes for pins...and I guess that means it is time for heat treat...and NOW I'm getting nervous!

All I have is a buddy's oxy/act torch. Should I try and rig up an oven (pipe in a pile of cat litter for insulation type of rig) with it, or just hold it with long vise grips and try freehanding it? (1095 steel, started at .125" thick, down a bit now from smoothing/polishing)

Is a gallon of oil (atf+motor oil) enough, or should I collect some more? Pre-heat the oil?

CDH,

Remember to drill a hole for the lanyard loop. You'll want one in a knife that big.

We use F drills for pin and lanyard holes so that the pins and tube will actually go in ... and have just a little epoxy around them.

Drill 1/8" holes in the guard, through the blade, for pins to assure the guard is hard fixed to the blade. This is done even if the guard is to be soldered to the blade.

Heat treat is usually done one of three ways.

1) Heat the blade in some sort of furnace beyond the critical point ... until it is just non-magnetic. Then full quench the blade in ATF/Oil. You can warm the oil to 100 degrees or so to make sure you don't crack the blade. A gallon of oil is enough if the tank is 4-6" in diameter. Otherwise you'll need more to get enough depth. A gallon is not enough to do many blades before it is allowed to cool. The mix burns very nicely thank you ... and it burns like mad when it boils!

Do expect some smoke when you quench the blade ... and (be warned) the smoke is flammable!

Check Wayne Goddard's book "The $50 Knife Shop" for designs of small and cheap furnaces. I think your blade may be too big for them though.

Don Fogg's site has a design for a nice propane fired vertical forge.

Fogg's Site

See Ron Reil's site for atmospheric burners if you don't want to use a blower.
Ron Reil's Site .

Then heat the back of the blade with a torch until the straw line just crosses the edge. This is a skilled endeavor and takes some practice. You can redo it if you do not heat the blade too strongly the first time.

2) High tech means: Either an electric furnace or salt pots can also be used. We use salt pots. See our site for a workable design. Not worth doing for a first blade.

3) Have the knife heat treated by Texas Knifemaker's Supply. A first knife is a trophy as well as a user. If yours is actually going to look like a knife ... I'd do it this way!

Hope this is helping!

Gonna try and post a picture here...



I think it'll make a somewhat respectable first one...just gonna need a bunch of polishing! How much do you polish before heat treat?

Oh, TKS says on their web site that they only do air hardening steels...so no dice there. I'll need to go ahead and pin the guard too...good though on the lanyward hole, I hadn't considered it at all.

quote:

Hope this is helping!

YES!

Looks good Keep up the good work

Cheers,

André

CDH,

Great looking work for a first attemtpt!

You might consider acquiring a piece of 1x3" hardwood, mounting it in a vise, clamping the blade to it by the handle, and working the surface of the blade with appropriate grits of sand paper.

Send me an e-mail about the HT problem. I think we can help.

quote:

working the surface of the blade with appropriate grits of sand paper

I'm sorta at a standstill on the finishing. I have been working with 320 grit belt and trying to vary the angles to smooth things out, and just get a nice crosshatch pattern. It shows in the picture. Should I just pick a direction (perpendicular to the spine) and work it until all scratching is in that direction? Engnath's web site has me a bit confused on that part. I wasn't aiming for a mirror polish, just a uniform working finish.

How much hand finishing is appropriate before heat treat?

On hand finishing...clamp to the benchtop and work parallel to the floor, or clamp in the vise and work perpindicular to the floor? Flat on the tabletop seems like a more natural direction and easier to hold square...maybe even clamp the handle to the tabletop and have the blade sticking out over the edge for ease of access???

quote:

Send me an e-mail about the HT problem. I think we can help

Your email doesn't show up in your profile. Mine is cdhcmh@gmail.com.

Thanks!
-Clayton