SCMI s520 manual/Tersa blades?

[Nick Crivello]

I just picked up a 1999 era SCMI s520 planer with Tersa head. Anybody have an owners manual? Or where to get one? These machines don’t change much over time, so an older or newer one would likely be useful.

Any good Tersa resources out there? Anybody have one of these planers, any tips/tricks to be aware of? Thanks!

[Robert LaPlaca]

Resource for Tersa knives https://tersaknives.com/

[Larry Edgerton]

If you have any specific questions I have the manual to mine. Second Tersaknives.com. Carbide is the answer.

[Nick Crivello]

If you have any specific questions I have the manual to mine. Second Tersaknives.com. Carbide is the answer.

Thanks, I'm in the process of getting it cleaned up. Will ask as issues come up.

$600 for a set of carbide knives.

Edit: I just pulled the existing blades out. Three different blades were installed..

[Nick Crivello]

So the HSS/M42 blades are ~$80 set vs $600 for carbide. Can you guys comment on lifespan between the two for common hardwoods?

[Larry Edgerton]

I bought the machine new and they gave me ten pair of HSS. They did not last very long. I tried M42, better but not that much. At first I just bought 2 carbide and ran two m42 with them, no problem whatsoever. Eventually I bought 2 more carbide, and I still buy them two at a time. When I turn a set to the second side I order a new set. I am getting thousands of feet out of a set, and the cut from the carbide is better than the M42/HSS.

I put a piece of tape on the underside of the hood and keep track of when they are new, when they are shifted, and when they are turned. I took a machinists stamp set and numbered all the knife slots on the cutterhead, so it would be "Shifted 2-4", "Turned 1-3," "2-4 New" and so on. I always change the odds or the evens according to the schedule written in the tape. You will appreciate how fast you can shift/change knives. I always start a new set a bit to the right so that I can get a good shift to the left as is needed.

[Mel Fulks]

I like T-1 , carbide is good for some things but brittle and never as sharp as steel.

[Robert LaPlaca]

Nick, I am not a pro, just a very serious hobbyist. I have running M42 knives in my MM FS41E, the M42 last for about 200 Bd ft of lumber for me. As of late, I mostly process Mahogany, with a bit of Cherry, the finish left by the Tersa’s is beautiful..

[Jim Becker]

Nick, the carbides will last a lot longer, but even new, they are not going to provide the same quality of finish that the sharper M42 or HSS knives will. Believe it or not, the cheapest "Chrome" Tersa knives are outstanding for cut quality on softwoods like pine, although knots can obviously present a challenge. On my FS350, I run the knives in the green cardboard tubes and they perform well for me. If I was going to be processing a lot of gnarly stuff, "extreme" hardwoods or reclaimed material, I'd consider the carbide knives but am happy with how things have worked for me for many years now with non-carbide knives.

[Larry Edgerton]

I like T-1 , carbide is good for some things but brittle and never as sharp as steel.

Sorry Mel and Jim, but in the case of Tersa you are wrong. Insert carbide is not the same as braised carbide, total different composition as it does not need to be porous enough to hold braise. Have run both in the same machine for thousands of feet and you are passing on bad information. The Tersa carbide cut is superior and in the end is cheaper.

[Mel Fulks]

Sorry Mel and Jim, but in the case of Tersa you are wrong. Insert carbide is not the same as braised carbide, total different composition as it does not need to be porous enough to hold braise. Have run both in the same machine for thousands of feet and you are passing on bad information. The Tersa carbide cut is superior and in the end is cheaper.

Reminds me of : “HOGAN ! Why was I not notified about this ? !

[Larry Edgerton]

Reminds me of : “HOGAN ! Why was I not notified about this ? !

Mel, I have conservatively ran 100,000 Feet through this planer, and as I stated I started out with steel. I too was under the impression that the cut of carbide was not going to be as good. The catalyst for the switch to carbide was a truckload of Jatoba. Jatoba would just fold over the steel knives, you could actually hear the knives change in one board. I called and talked to the folks at Tersa and they explained the differences in inset carbide and braised and so I ordered a pair much as I hated paying that much. The pair, coupled with a set of dull steel knives planed that whole truckload with very little degradation. I have been using them ever since. I save the old ones, in fact will throw an old set in if the wood looks dirty for the first pass, and in over 20 years of commercial planing from rough I have use 14 knives not counting the 4 in the planer. I need to send them in to be sharpened and I will be set for the rest of my life.

This is a business, and I keep track of costs. Carbide Tersa's are cheaper and you may not believe it but the cut is better. I was worried about chipping but that has not been the case. I suspect it is because a Tersa head has almost no knife projection. The steel knive chipped/nicked much easier.

[Brian W Evans]

I am currently using carbide knives in my MM J/P. I have run several thousand feet of ash through and there has been no degradation in the cut quality, which is excellent. I have been surprised at how easy it is to sand to a finish-ready surface.

I do not have Larry's long perspective but my experience seems to confirm what he says.

[Jim Becker]

Sorry Mel and Jim, but in the case of Tersa you are wrong. Insert carbide is not the same as braised carbide, total different composition as it does not need to be porous enough to hold braise. Have run both in the same machine for thousands of feet and you are passing on bad information. The Tersa carbide cut is superior and in the end is cheaper.

You are the first person to my memory that says that the Tersa carbide has a superior cut...even the sellers don't say that. I'm not suggesting your experience is bogus; just that the statement doesn't jive with what's been said historically here and elsewhere. Perhaps I'll spring for a set at some point.

[Joe Calhoon]

I came to the same conclusion about Carbide Tersa Larry. It’s expensive but when you do the math with lineal footage it becomes obvious what the most economical route is. The other thing about carbide Tersa when it’s dull you still get a fairly good surface finish.
i run Tersa Carbide in the S4S machine and fully expect 10 to 15 thousand LF before turning the knives. I have also had good luck with coated HSS Tersa clones in the Kanafusa and Lietz brands.
I spent many years using straight knife conventional heads with T1 steel. No thanks for any more of that!

Same is true with well engineered insert carbide shaper cutter heads. If you have used these with the T10 sub micron inserts that will make a believer of you.