Tersa Cutterhead for Delta & Powermatic Jointers & Planers?

[Al Currano]

Newbie on this site - first post. Great site.

I have a Powermatic Model 50 6" jointer, and will soon be the proud owner of a Delta DJ-20 (M/N 37-350) 8" jointer that I got a pretty good deal on used. Once I pick up the DJ-20 I'll be giving the Powermatic to my son, who is in the process of setting up his own workshop. I am also getting a nice Delta DC-380 15" planer from the same source.

I've read a lot of good things about the Tersa system, particularly how easy it is to change the knives, as well as the quality of the jointing & planing. But much googling and searching of this forum, I have not found a source for replacement cutterheads for my jointers or planer. I am getting the impression that the only way to get the Tersa cutterhead is to buy a jointer or planer that has one designed into it by the mfr. Is that the case, or are there sources for aftermarket Tersa cutterheads for Delta and Powermatic machines?

Thanks in advance for any insights y'all may have.

[David Kumm]

I think you can get Terminus but not Tersa for those machines. I'd put a Byrd on the planer and maybe ESTA on the jointer. I don't mind changing knives but the ESTA are a cheap alternative and i don't need a shelix on a jointer. Other like it though. The knives are hard to change on the 380 so that is the one I would spend $$ to change. Dave

[Al Currano]

I think you can get Terminus but not Tersa for those machines. I'd put a Byrd on the planer and maybe ESTA on the jointer. I don't mind changing knives but the ESTA are a cheap alternative and i don't need a shelix on a jointer. Other like it though. The knives are hard to change on the 380 so that is the one I would spend $$ to change. Dave
Dave - thanks for the quick reply.

However, the Byrd for the 15" planer is $795 from Holbren. That is approximately $200 more than I'm paying for the planer itself :eek: The Byrd for the 8" jointer is $445, which is "only" $200 less than I'm paying for the jointer :(

I can get knives sharpened for .50/inch, which is $12 for a set of 8" jointer knives, and $22.50 for a set of 15" planer knives. I can buy a brand new set of Schmidt T1 HSS 8" jointer knives for about 44 bucks and a set of the 15" planer knives for about $78. So I can go through 10 sets of replacement knives or a whole slew of sharpenings before I expend the same amount of cash as I would for the Byrd cutterhead. Only downside I can see is the time to replace the knives, which is one reason I was looking for the Tersa cutterhead, since it is supposed to take less than a minute to replace a set of 3 Tersa knives.

Doesn't seem like a good investment to me. Personally I'd rather spend my (limited) cash on building up my stock of quality hardwood for future projects.

And no, I don't do a lot of planing of highly figured wood or curly maple or the like, so for me that doesn't factor in at all.

[David Kumm]

Al. you are preaching to the choir as i'm a straight knife guy unless they are hard to change. A Tersa upgrade would cost more if available than the Byrd which is why I assumed you wanted out of the regular cutterhead. ESTA are a cheap alternative for the planer as that is the tougher of the two to change unless you reference the head and the head is parallel to the base. Dave

[Mike Heidrick]

What the math behind your tersa solution?

[Al Currano]

Hi Mike - I don't have a Tersa solution, since I hadn't found a source yet for the Tersa cutterhead. However, based on Dave's last reply, it sounds like the Tersa cutterhead will cost more than the Byrd, so obviously the math doesn't work out there either. Guess I'll look into ESTA; haven't done that yet. Or, just set the blades to the head after ensuring that the head is parallel to the table, which is what I have been doing up till now with my trusty, crusty ol' Belsaw 912 planer.

Al

[Mike Heidrick]

What is ESTA?

[David Kumm]

What is ESTA?

Disposablade system. The original Felder system was ESTA. Thin double sided blades in holders. You set the holders with the blades and then just swap the blades in the holders. Can reference off the jack screws or the cutterhead. The blades can be shifted a little sideways to help with nicks. I prefer the mass of regular knives on my large machines but they give a very fine finish- particularly on 12" and under machines with smaller diameter heads. You do have to make sure to not get crap in the slots but generally makes blade changing a 10-15 minute job at worst. Dave

[Peter Quinn]

We have terminus heads in several machines at work and on most of the molders for the final finish heads. They are available or can be made for pretty much anything, you might have to get some measurements to have one made as these things are generally built for industrial machines, and none of the machines you are considering are really in that category. So probably no off the shelf solution available. But generally, terminus head and "small fortune" are spoken in a single breath. The only hobby level machines yo see them on are the expensive European kind. They are great for speed of knife change where you are loosing money every minute your machines are not being fed wood, but for the home shop? Somewhere between really nice luxury and massive overkill IMO. Oh, and the knives are not what I would call cheap by the inch either. We have a 20" jointer with terminus head at work, the first 12" gets worn out first, but the boss gets to pay to replace the whole 20! Ouch for him, but its way quicker to change knives than it used to be, though now we ride them until they are dead and them some to keep the cost down. They are reversible and can be sharpened a few times, still not cheap.

On the byrd heads, they last about 20 times as long as HSS, so the 10X sharpening factor is only half way to the truth. No matter how you slice it, they are cheaper in the long run, but I understand the short run budget realities. As it turns out I have both a DJ-20 and a DC-380 in my home shop, and after years of use I converted them both to byrd heads. I don't miss the knife change routine even a little tiny bit, though I got pretty good at it. Its been over a year, working on 2 on the jointer, still on the first side of the original set of knives. Some teak, some BE maple, a but load of ribbon mahogany, jatoba, QSWO, plenty of hard stuff has gone over them. Still razor blades, no tear out. Best thing that ever happened to both machines IME.

Good luck with the new tools. I'd get them set up, get used to the straight knives a while, learn the set up with those, then look at the options for heads or insert holders like the ESTA system. I've enjoyed having both machines in my shop. Good little work horses.

[Jeff Duncan]

One thing that seems to get overlooked with the Tersa's is how you change the blades. They slide out sideways.....meaning if your machine was not designed with Tersa in mind, and the DJ20 was not, it won't work;)

So the question becomes why do you want to replace the head? If we know that maybe we can better steer you towards a solution. I for one think the insert heads are nice if not a bit over rated? If your only concern is changing knives you have to figure out how often you'll do it. My 16" jointer planing mostly domestic hardwoods goes over a year between sharpenings. I think it's actually close to 2 years now....though it's a bit overdue:eek: My 8" jointer gets less use and I have not changed the blades since I bought it several years ago. So if you have to change the blades once a year and it take about a half hour what are you really gaining with an insert head? If you have to change them once every 3 or 4 years? All comes down to what woods your planing and how much use it gets. With an insert head and occasional hobby use I seriously doubt you would ever need to replace the carbide cutters from wear.

good luck,
JeffD

[Stephen Cherry]

I used to think about going with a byrd head in my grizzler 12" Tiawanese jointer, but after I started sharpening in place with a stone in an old craftsman router, I haven't seriously considered it.

Takes just a few minutes, only adjustment after sharpening is outfeed table height.

[Al Currano]

When I posted this I was thinking primarily of the DC-380 planer, since I have heard it is somewhat more difficult to change the knives than many other planers. But at that point I hadn't checked the price. I almost fell off my chair when I found out it was almost $800 for a Byrd cutterhead. So that is not going to happen anytime soon. If I had $800 to burn I'd rather invest it in a higher-end used 18" or 20" planer than fork out more than I paid for the DC-380 just to upgrade the cutterhead.

As for the jointer, I'm used to changing knives on the Powermatic and it's not too bad. One reason I might do it is if I started nicking the blades a lot. We've recently been running some rough air-dried oak from a downed tree with some tough knots and a little bark on some of the edges through the PM 50 and have already nicked the blades at least once. In the long run it could pay to switch to the Byrd once I get the DJ-20 up and running, but for now I'll stick with the straight blades and see how it goes.