Woodworking Talk banner

1 - 20 of 31 Posts

·
Super Moderator
Joined
·
3,344 Posts
Discussion Starter #1 (Edited)
as my "spare time" keeps getting extended, I will be undertaking my next
project of making some carving knives. (then I will learn how to carve).
I see on 99% of the YT videos, they are all about just "making" the knives
out of a saw blade with no heat treatment or tempering. there are no
followup videos of how well they hold up under different carving projects.
what do YOU do, if anything, to the blades before putting them in handles ??

knife handles 012.jpg

knife handles 007.JPG

Knife 2 015.jpg
I made this one last week - no heat treatment - just fabricated cold steel.

.

.
 

·
Super Moderator
Joined
·
4,855 Posts
That is a good looking knife. I have used several different things to make carving knives but mostly I have used an industrial hacksaw blade. The toothed edge is high carbon steel tempered to where it is almost too brittle for a small knife blade. I have snapped a blade already because it was too brittle. It will really hold an edge for a good while but just have to be careful not to pry even a little with it.
 

·
Village Idiot
Joined
·
4,977 Posts
You have summoned me

Strictly speaking, when youre making a knife from something prehardened like a sawzall blade as long as youre careful about heat when youre grinding out the blade, you dont have to do anything regarding heat treating. The steel is still as hard as it was in the saw blade form, which is hard enough to hold an edge. Technically. Far as im concerned though, reciprocating saw blades make for crappy knives for a couple reasons.

First off, most reciprocating saw blades arent just one kind of metal, theyre 2: the spine is made of something soft and springy, the teeth are made of somethimg much harder. Reason for this is if you made the entire blade out of the hard stuff it would break instead of flexing, which would reduce its lifespan, and if you made it out of the springy stuff the teeth wouldnt hold a good edge. When you grind a knife shape, youre usually left with just the springy stuff, which makes for a crappy edge. Now, you can still find blades that are monosteel, the same stuff throughout, but even then the steel is usually tempered to favor flexibility over hardness, to let the blades bend instead of breaking. A little bit of flex is good, too much flex makes for a crappy edge. Doesnt matter in a saw blade, matters a lot in a knife.

When it comes to heat treating a saw blade, to try to get the properties you want out of the steel, youre left with another problem; you dont know what kinda steel youre dealing with. Different steels need to be heat treated differently, and if you dont know what you have youre flying blind. You could be dealing with L6 steel, which you can just heat to cherry red, hold for a few minutes and quench in oil, but if thats actually D3 steel then quenching it will cause it to crack. Getting the best results from heat treatment requires knowing what youre dealing with, flying blind can get you something workable, but its a lot of extra work for a very unknown benefit.

Bottom line, if youre going to make a carving knife from a reciprocating saw blade or similar, theres no real need to try to heat treat it. The steel is already hard-ish and will make a decent knife. If you want to go through the trouble of heat treatment to make a great knife, it makes more sense to start with a known steel. Its surprisingly inexpensive in small amounts too, a piece big enough to make a carving knife from is only about $7 at a place like McMaster:
https://www.mcmaster.com/o1 tool steel/oversized-multipurpose-oil-hardening-o1-tool-steel-bars/

Grind your knife form, heat it up until it no longer sticks to a magnet, quench it in canola oil, toss it in the kitchen oven at 450f, polish, sharpen. Pretty easy to do honestly
 

·
Registered
Joined
·
155 Posts
Very interesting topic. I was told that old car leaf springs made good knives.
Iron and steel make a fascinating subject to explore. I recently found that Swedish "iron" used in the old days as it contained a natural correct % of carbon. Swedish steel swords were highly praised.
johnep
 

·
Super Moderator
Joined
·
3,344 Posts
Discussion Starter #5 (Edited)
thanks Jim !

Epic - I made some carving gouges back in the '80s out of material
I got from McMaster Carr. I still have a lot of it left but I have no clue
as to what type it is. After heat treating, I put them in the oven on the
"clean" cycle and they reached the nice straw color. but, 3 of them
snapped at the tang. so that was a learning cycle there.

as for palm sized chip style (whittlin) knives, all the blades are less than 2"
and I used the tooth side for the cutting edge, being careful not to overheat
during the sharpening process. I just didn't understand all the videos of
why they didn't heat treat the blades before putting in the handle.
I think I got it now - thanks !
(I love my new[to me] 14" Delta band saw. I've slowed it down enough to
accept a 1/2" metal cutting blade and it is awesome. I cut up a circular
saw blade awhile back with little effort. so I know I can cut all the recip
blades to shape very quickly without using the angle grinder.

Johnep - yes, the car springs made prior to WWII is the best tool steel.
but - unless you have a full on forge and 500 pound anvil and three
monkeys to swing the hammers, it is a grueling task.

I bought a WEN oscillating spindle sander just to shape the handles with.
it will be here Sunday. I like making things like this and will probably
give most of them away.
my geographical area is still growing for the Covid issues and I am taking
extra steps to stay out of public places. so in-home hobbies are at the forefront.
what's next ? I have plenty of mallets, LOL.

stay safe everyone !!

John

Edit:
here are the sheets of tool steel I bought back in the early '80s.
I will probably never use it all in my life time - especially the thick stuff.
(I guess I should at least clean them up and spray with some clear finish
in case a future generation wants to make something out of it).

tool steel 002.JPG

tool steel 003.JPG

.
 

·
where's my table saw?
Joined
·
27,893 Posts
Spark test for steels .....

thanks Jim !

Epic - I made some carving gouges back in the '80s out of material I got from McMaster Carr. I still have a lot of it left but I have no clue as to what type it is. After heat treating, I put them in the oven on the "clean" cycle and they reached the nice straw color. but, 3 of them snapped at the tang. so that was a learning cycle there.
.
.

(I love my new[to me] 14" Delta band saw. I've slowed it down enough to accept a 1/2" metal cutting blade and it is awesome. I cut up a circular saw blade awhile back with little effort. so I know I can cut all the recip blades to shape very quickly without using the angle grinder.
John
.

As far as knowing which material you have there is a spark test for determining how much carbon content is within the steel. It probably won't differentiate within the better knife making and hardenable steels:


This one will give you a better feel for the type of steel:


John, you said you "slowed yours down enough". What did you do specifically? A jackshaft, a gear reduction unit?



Slowing down a standard wood cutting bandsaw enough to permit metal cutting, that would require going from 3,000 FPM down to 300 FPM or even less, about a 10 to 1 reduction:

https://www.highlandwoodworking.com/woodworking-tips-1205may/askthestaff.html

For cutting steel:

https://www.sawblade.com/band-saw-blade-speed-and-feed-chart.cfm



I love all my bandsaws from the 18" MinMax woodcutting resaw to the 10" Craftsman hobbiest I got when my son was 10 years old. Then there are two metal cutting bandsaws, a 10" capacity vertical Roll In with a 4 step pulley reduction as well as a gear reduction and a very old Craftsman horiztonal type with a pulley and bevel gear reduction system. Drill press and lathe operations use the same cutting rates as bandsaws. Roughly 1,000 to 3,000 CFM in wood depending on the bits and type of wood or down to 300 CFM in steel depending on the type also:
https://www.pinterest.com/pin/586593920186165656/


I have learned a lot by doing things wrong and wondering why my bits heated up and dulled especially in stainless steel which is not only hard, but tough. Aluminum is kinda in between since you can use a woodcutting blade in your bandsaw at pretty much "normal" speed without any damage to the blade.

https://www.pinterest.com/pin/586593920186165656/




:vs_cool:
 
  • Like
Reactions: John Smith_inFL

·
Registered
Joined
·
1,293 Posts
John Smith, I made a Small hand plane using a Bi-Metal Sawzall blade, and it is a favorite. It holds an edge as well as any hand plane. It is a one of a kind and has a 1/2" cutting edge. I originally made it to smooth the bottom of dado's (those ridges). I found that it works extremely well for detail type chamfering and rounding and get can get into many tight inside corners. My original thought was to heat treat the steel but found I didn't have to. I ground the teeth off being careful not to heat the steel then shaped the blade with a single cut file using the draw file method to get the width. I used calipers to get it precise. The edge was done using a honing guide (as I would a chisel or a plane iron). I left the shape of the Sawzall blade to show what it was made from. I have made about 15 different hand planes and many scrapers and usually use O-1 steel (Starrett), going through all the steps to shape, heat treat and anneal by using a Bernzomatic torch.
 

Attachments

·
Village Idiot
Joined
·
4,977 Posts
John- Blades snapping at the tang is actually a pretty common problem, and it isnt always the fault of the heat treatment process. Tangs are an area where all the stresses seen by a blade tend to concentrate, youve got all the force that the blade portion sees being funneled through an area that sees a pretty dramatic reduction in size. If you have something like a sharp corner at the junction of blade and tang, you create a stress riser and nearly guarantee that the blade will snap there if it sees too much force. Proper geometry for the area is a lot more important than it seems at first glance.

Glad i could help clarify the need for heat treatment. Like i said, you can make a decent enough edge out of a sawzall blade without heat treating it, probably make for a better knife than a commercially available one to be honest. Just dont expect it to outpreform something made with a known steel thats been heat treated properly
 

·
where's my table saw?
Joined
·
27,893 Posts
Reusing sawzall blades ...

I was informed of the Milwaukee "The Torch" as the best sawzall blades for metal cutting, and sure enough they are!

https://www.amazon.com/Milwaukee-Torch-Sawzall-Blade-48-00-5782/dp/B000F713BS


I don't know about the rest of the blade body, but the teeth will cut faster and better than any other blades I've used. If you want to try some I'll figure out how to send you a few.... let me know via PM.
:smile2:
 

·
Super Moderator
Joined
·
3,344 Posts
Discussion Starter #11 (Edited)
Band Saw Speed Reduction (FPS)

John, you said you "slowed yours down enough". What did you do specifically?
A jackshaft, a gear reduction unit?
Slowing down a standard wood cutting bandsaw enough to permit metal cutting,
that would require going from 3,000 FPM down to 300 FPM or even less, about a
10 to 1 reduction:
:
I bought 4 inexpensive pulleys off of E-Bay and I had some on hand already.
then made about 3 or 4 trips to my local NAPA for V-Belts until I found the
right combination. (I returned the unused pulleys and belts to the seller).
fortunately, the person that I bought the saw from had already used it for cutting
metal in his automotive shop - but used really small pulleys, (IMO). too high FPM.
he fabricated a really nice motor-mount slide that is Jam Up and Jelly Tight !!!
so, with all my stars lined up just right I ended up with a 14" pulley on the saw shaft
and a 2" pulley on the motor and a 57" V-Belt. (of course belt length will be different
with each saw. I don't think many people have the adjustable mount like I have).
[I should take some photos of that too, it is really simple to make with minimum tools].
I looked at the speed reduction formula on the net and I think it was in the
3-400ish FPM realm.
(I could probably still go to a 15-16" pulley, but it is fine for me at the moment).
at the time, I was cutting up aluminum scrap to melt in a forge and wasn't
cutting steel, like I am doing now for my "new project" of making some knives.
CAUTION: IF YOU INSTALL THIS SETUP, EXTREME CAUTION SHOULD BE
EXERCISED TO ENSURE PETS AND INQUIRING KIDS FINGERS CAN NOT GET
INSIDE THE MOVING PARTS !!! This design is NOT OSHA approved !


Speed Reduction.JPG

here is a leather maker's "Head Knife" that I made a couple of weeks ago.
no need to describe the process - it is self explanatory.

skiving knife 013.JPG

skiving knife 016.JPG

skiving knife 034.JPG

.
 

·
where's my table saw?
Joined
·
27,893 Posts
A jack shaft would give you more speeds ....

By putting a second shaft between your motor pulley and machine pulley you can reduce the speed even further. I did that years ago on a Crappy Craftsman 12" saw, which was never meant to cut steel and did only a fair job on wood. I sold it eventually and upgraded considerably. Not knocking your workout at all, just throwing a suggestion in if you want a greater reduction ratio. If I recall 100 FPM is the best speed for some steels ...... ?
:vs_cool:


 

·
Super Moderator
Joined
·
3,344 Posts
Discussion Starter #14
Home - I "had" a Lenox DIEMASTER 2 Bi-Metal 16-TPI blade on it.
yesterday, I wasn't paying attention to what I was doing and
I cut a piece of 3/16"" mild steel plate and forgot to
change out the pulley from a 6" to the 14" and ruined the teeth
on the blade. aaarrrggghhhhhhh pretty frustrating.
today, I ordered two 3/8" and one 1/2" 18TPI blades. and will
pay more attention to the speed configuration in the future.
with the 14" pulley and the slow speed, the 16TPI blade had no
trouble cutting the table saw blade to make the leather cutting knife.
I will be constructing a guard soon for the pulley and belt before I
get caught up in it myself. (that is Job #2 on the list).

John

.
 

·
Super Moderator
Joined
·
3,344 Posts
Discussion Starter #15
update: this is what I started with. I bought the WEN Spindle Sander just
for this project and it works great. all the blades were heat treated and quenched
in Canola Oil before putting it in the handle.
I have to put the final sharpening off until I can get to Walmart for a box of bandaids.
handles are of assorted woods of unknown heritage and have 4 coats of Danish Oil.

knife handles 012.jpg

knife handles 007.jpg

knives.jpg

.
 

·
Registered
Joined
·
334 Posts
John, those look like very nice carving knives.

Thank you John, et al, for this very cool thread. I've thought about making some tool blades, and this thread answers a few of my questions, specifically about steel blank sourcing and identifying types.
 

·
Super Moderator
Joined
·
3,344 Posts
Discussion Starter #18 (Edited)
thanks guys !!
the first half dozen, I was impatient to get it done. I only flame hardened the blade
and glued it in the handle, withOUT buffing and sharpening the it.
now I get the blade fully finished, half sharp, and high buff on the buffer.
THEN glue the blade in. the excess epoxy can be sanded off cleanly and the excess
blade trimmed off. a run on the router with a 1/4" round over and finish shaping on
the spindle sander and some hand sanding - very relaxing once you get the hang of it.
if you make your own, don't rush it. have a box of bandaids nearby.
I just pulled a bunch of examples off the internet and sort of made the pattern from there.
most will probably never be used - I just enjoyed making them.
(Mr. Yamato has inspired me to get back into the carving hobby).
I love his mallets and will be making a couple of those too.

.
 

·
Registered
Joined
·
26,362 Posts
What do you think you would like to carve? I've been carving most of my life and have never used a carving knife. Occasionally when I need a knife I will use a utility or exacto knife but that is all. I do most everything with chisels.

I use a round mallet which I made out of ash turned on a lathe. Then to add some weight I drilled a 1 1/4" hole in the head of it and filled it with lead with a wood cap behind it.
 

·
Super Moderator
Joined
·
3,344 Posts
Discussion Starter #20
I am not a "carver" per se, I am just a piddler and collect tools.
a few of my projects are in my photos here.

.
 
  • Like
Reactions: BigJim
1 - 20 of 31 Posts
Top