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.