cutting down jointer knives question

[Warren Lake]

Have to cut some knives down for one jointer. Took one of the originals 20" and set this up. Second photo are the new knives. T1 18 Percent Tungsten and 24" long. I dont see doing this on my metal cutting bandsaw and have not cut jointer knives down before.

I have the cold cut off saw which I had to buy to make a stair case as it would not fit on my metal cutting bandsaw. In looking on the net seems most people run cold cut saws with carbide blades but they were cutting different steel than these knives. May or may not matter. New knives are 1.125 thick approx and 1 1/4" wide.

I have a fibre wheel and it will wear. The knife could be standing up but figure down is better as it will wear less of the side of the fibre wheel. As the bottom wears away then it will expose a fresh side surface.
Ill do a test cut on an old knife first. Am I on track to cut this way? Will I need cooling? figured cut a bit then use compressed air to cool. I think I have tons of non ferrous blades but not any ferrous but will check. Warps my mind seeing people cutting steel with carbide saw blades. Just used to the tool and die maker and car builders and all of them had metal cutting bandsaws.

Do you need to weigh the knives after and if so to what resolution? I have a kitchen scale and it goes down to a gram but not tenths. Sure i read in the past picky shaper guys balance to a tenth of a gram.

Old knife for set up , New knife to be cut

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[Andrew Hughes]

If those are the New t1 knives Amana sell check to see what they weigh. I just recently rejected 3 sets of t1 from Amana because unbalanced weight.
My size are 12 long 1.5 wide 1/8 thick. I try for no more then 3 grams difference.
What I’ve found is they are sending stock at different thickness.
I got no experience on how to cut them.

Good Luck

[Richard Coers]

The softer the abrasive wheel the better, it will wear away faster and constantly exposing fresh abrasive. https://www.youtube.com/watch?v=l9-gmHf_Amw
My brother was a millwright. They used the carbide tipped cold saws for cutting a light gauge railroad system for parts retrieval. Those saws have much lower rpm than abrasive chop saws.

[Warren Lake]

thanks the you tubes i watched most were for the 14" Fein saw and Fein Blade, they motored through steel like it was poplar. These knives are Kadur from Dimar. I was going to weigh the old ones so will do the new ones first as well. Seems bizare Andrew on those different weights all the same on knew knives and good you checked. Im sure I have thicker knives from the SCM jointer but will have to check.

[Andrew Hughes]

I fail to mention I did eventually find one set of 3 that were good one knife was 2 grams heavy. I can shorten the length to make that up. But not until they come back from the saw service guy. All three are horribly crowned.
Good t1 is rare now I guess your lucky to have found some I hope they work out perfectly.
Here what I got.:(

[Warren Lake]

thats crap to come that way. On the general they sharpened once and they were down .015 in the middle. I can still get perfect as you clamp the center then tap down the outside to straight but should not have to do that. I put another set in and sent them back and they re did them saying issues with their machine.

[Philipp Jaindl]

Not a Metalworker so dont quote me on it but from my limited knowledge Carbide chop saws arent meant for hardened Steel meaning it might dull the sawblade pretty fast or damage it not that it wont necessarily cut it. Again i may be wrong.
Personally i'd take it to your local metalworker or sharpening service and have them do it or failing that try with an Abrasive Chop Saw or maybe even angle grinder but go slow, use plenty of cooling and just try your hardest not to overheat them.

Regards Philipp

[Bill Dufour]

A abrasive dry chop saw will burn the temper near the cut and ruin the blade.
Bill D.

[Mel Fulks]

Everywhere I worked always used the aprox I/8th thick cut off wheels. I like for the steel knives to all come off the same
bar. With high quality steel knives if they are same length they all weigh the same. The cheap standard stuff will sometimes have 7 inch knives that are not the same weight at same length, sometimes one will be almost 3/16 longer.

[Mel Fulks]

Many years ago I was rebuked for cutting HHS steel too slowly with the fiber -grit cut off wheel. Most I've seen use the wheels with
some downward pressure. Especially with moulder knives longer than the actual moulding will be.

[Mike Kees]

A abrasive dry chop saw will burn the temper near the cut and ruin the blade.
Bill D.
I have the same exact knives and my sharpening service cut them with an abrasive wheel chop saw. It does not ruin the blade. There is a small blue mark where the blade is cut,maybe 1/16". Has no effect on the blade as a whole.

[Mike Kees]

I would stand the blades up on edge though. This will cut quicker and keep the cut cooler.

[Ronald Blue]

If they are truly T1 tool steel you won't hurt them by using the chop saw. Like Richard said a softer wheel is better. It may still want to glaze up if you aren't careful. When you start the cut keep it going to keep it breaking down.

[Warren Lake]

first two cut fine third cut and started to not cut well most of the way through. Im going in and out with compressed air and keeping it pretty cool. This fourth knife its like it stopped cutting decent on the third one. The fourth the fibre wheel goes in then shoots off the side. I had to stop at least its going off making the knife longer. I tried one of my hand air grinders but going to leave it till tomorrow. Face mask hogs up and and, now seeing this fibre wheel flex and skate away. I got the saw name brand to do that one job, memory said I wasnt impressed. I have a metal wheel, dont see numbers on them for hardness. Not impressed. I did a test cut first on the same steel and its hard and go slow. I went in and out so I could cool it the best compressed air in my left hand. Now thinking about it strikes me the last two I was using the air as I was cutting as well and likely blowing the wheel over. Still it seems like it loaded up or something. Wheel was 3/32. Are you supposed to use a cleaning and truing tool on them?

ILl have to hand cut it off then bring it to length some other way to match the others. Weighed them before and after and will check those measures. Ill try turning the knife over and cut from the other side and not use the compressed air when the wheel is into the metal.

[Ronald Blue]

Look at the wheel and see if it looks shiny. This sounds like a classic case of the wheel glazing. Do you have a dresser stick or wheel like you would use for dressing the wheel on a pedestal grinder? Maybe you could touch it up if so.

[Warren Lake]

did look at it wasnt loaded but did see some silver there. Its also round front edge now and worn on the sides a bit. I have two types of wheel dressers the wiggle metal discs that spin and a diamond dresser. I think the diamond one might make more sense than those wiggly wheels that spin same time. both of these work fine on my grinder wheels but never used them on a fibre wheel. NO question it changed and just started towards the end of the third knife. ILl try dressing then flip to the other side. I didt stand the stuff up felt it better to be flat but maybe wrong on that. I still felt the side of the wheel would wear and knives get longer as I went. Might have been a better choice.

[Ole Anderson]

Angle grinder with 1/16" thick steel abrasive cut off wheel. Blade stood on edge. But I have cut all sorts of stuff with my Kalamazoo 10" cut off saw with a 3 hp Baldor motor. Again go with the thinner 1/16" wheel, blade on edge.
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[Warren Lake]

in the hand die grinder I did use 1/16 all the time. I could have and likely should have used that and didnt put the time in I normally do reading and testing. I did the one test cut and it was fine, so were the first 3 then that third one had a bit more than a wander burr towards the end. All fine I still have something to work to and if I flip it I could clamp a block of wood on at length and use it as a guide and run the 1/16 wheel down cutting from the backside forward. So nothing lost. This steel cuts nothing like most of the other steels i work with then I use the metal cutting saw half the time as well. Looked at the photos fast and the first three knives all weighed 362 grams.

Put them on a straight edge before cut and they were ou, worst about .01t. They looked unused originall but can see they were in and used in one area only but not much wear seems odd why they would have come out. Its odd as they are sharp over lots of the knives and had cut nothing. Either way will go in for sharpening.


Yeah Ole did go back with the 1/16 wheel in a hand die grinder with wood as a guide. Turns out it also slipped the last knife in the jig. The 1/16" worked well and cut many times faster. Sure there was a better choice of 14" wheel to have started with but agree with you on the 1/16 cut off wheel. The other wheel was 3/32. It cut three and 3/4 knives then start to fail and it wasnt enough that I noticed any big change. On the fourth wheel it was failing fast and I was wondering but thinking im just going slow. The head protection stuff is not in order. Need safety glasses need reading glasses, face shield and light to see. Then the stuff starts fogging up. Last years all metal cut with with the metal bandsaw.


Does anyone get jointer or planer knives hollow ground? I seem to remember they were hollow ground way back then at some point everyone went to a straight grind, some with finer final finish than others. And for those who have checked what type of tolerance are we looking for on a 20" knife for straightness.

[Warren Lake]

Knives were cut and last one messed as it pulled in my jig. I used the edge sander to shorten three to match the one last one where things went sideways. All three weighed the same one was 10 grams less than the others. I measured them all and it was a bit thinner. I took the other three that were all the same weight and ground off two grams. In the end with the one cleaned up there is 9 Grams difference with three the exact same weight. Knives are 20"

Here are the gibs cleaned up with one locking nut missing, or its here but thats the same as missing. It went out to double check buying a few wrenches. The gibs all weighed exactly the same but one that was drilled out int he end??? if that wasnt done then it would weigh the same or very close so see if it can be filled with something.

The middle four knives are the ones I just cut the T1 ones. Ive talked to the distributor and will go visit him and show him a few things and ask before they get sent out. They were new but in a machine for some period of time, both ends still sharp and show the people who put them did not hone them first. The previous knives in it are the four at the front, you can see one of them came from different knife stock, heavier it was the thickest knife as well.

David said it may not make a differece to a large heavy head and that is a good point, this is not a shaper head with two knives where balance is critical.

There are some sort of specs for this stuff and id say as Mel said same length they should weigh the same. Also with some of those weights of the originals one that is thinner is heavier than some others so that says more. Then also for straightness as these knives are not straight either the back side or the edge surface, that would be down from some wear in use. so that makes me wonder about the back of the knife spec, id assume its plus or minus zero and that is important in the jig it sits in when they grind but dont know that part of the process.



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[Andrew Hughes]

I’m a believer in all the knives should be cut from the same bar stock. Different thickness can lead to other problems with springing the head.
I swear this crappy knives selection is new to me as my Older knives from Amana T1 made in Germany are exactly the same thickness and perfectly balanced. They are just getting short in width.
The m2 knives from American National knives are also perfectly balanced.
I often wonder if part of the reason many have trouble setting knives is because they are different thicknesses.
Good Luck Warren thanks for sharing your results.

[Warren Lake]

The middle ones should all be the same, one is not. The bottom four that is last owner so at that point it had a three set in it and one more supposed to match and didnt.

Ive never weighed or checked this stuff before. Knife thickness should make no difference other than weight. Its a gib with a bolt pushing it against the knife, it doesnt care about thickness. Setting is the same you are working to the tip of the knife, they should be the same but its not going to make a difference with setting them. I set them with a dial and am only measuring the tip above the head, how much projection then make the others the same.

[Mel Fulks]

My experience has been that T1 ,and other premium steels, that are cut to exactly the same length will weigh the same.
I guess you could save money and not buy a scale. With the low grade stuff knives cut from same bar to exactly the
same length can need an 1/8 th or more removed from a 7 inch knife to balance.

[Andrew Hughes]

My sharpening service has warned me about using knifes from different bar stock.I have no scientific way of measuring the difference a thicker knife makes.I do know that when the knives get to be the same size as the gibs they are finicky to set.
The Head is affected from the pressure at the top of the knives pockets.
Im guessing they see this problem more then me and I’ve just recently seen t1 knives from China that varied more then .010.
A heavy knife in my 3 knife head vibrates the whole jointer.
Good Luck