Terminus cutter heads?

[Chris Rosenberger]

Has anyone used the Terminus cutter heads in planers & jointers?
Are they good or bad?

Chris

[Joe Jensen]

Love the head. I'm now trying to decide between a Terminus or Byrd head for my 12" Powermatic Model 100 planer...joe

[Chris Rosenberger]

Thanks Joe. I just installed a Terminus head in a Powermatic 180 this evening. It looks very nice. I could not believe how easy it was to install the knives. They just snap right in. No adjusting at all. Tomorrow I will get the feed rolls adjusted & electric connected. Then I can see how well it will cut.

[Joe Jensen]

I'd like to know what I'm in for. I spent nearly a whole day dialing in all the measurements when the planer was new. But, I got everying +/- .0005 across the entire 12". Should be easier with the knives all in the same arc...joe

[Dev Emch]

I'd like to know what I'm in for. I spent nearly a whole day dialing in all the measurements when the planer was new. But, I got everying +/- .0005 across the entire 12". Should be easier with the knives all in the same arc...joe

O.K. Now you got me curious. Exactly how did you dial in a planer to maintain 5 tenths across 12 inches?

[Joe Jensen]

I have a very good dial indicator and fixtrue for planers. With my planer, I had to have the chipbreaker and pressure bar machined as they were not flat. Once that was done the bed rollers, chipbreaker, and pressure bar were not very difficult, maybe an hour. The knives on the other hand take me 3-4 hours to set. The the knives creep when you just touch the cutterhead. With the planer set this way it cuts wonderfully, but I end up waiting too long to change them. My process for milling wood is as follows:
1) Rough cut rough lumber to length and width
2) Surface one side on the jointer until flat
3) Use planer to surface other side and to plane to final thickness
4) Joint one edge
5) Cut to finished width and length

With the approach I get flat and straight wood, but it's tough on knives. I'm torn between a Terminus for the planer ( great finish, some tearout on figured woods, knives wear faster on rough wood), and a Byrd carbide spiral head. (great durability, but I'm uncertain of the quality of cut and flatness of the panel.

[Chris Rosenberger]

Joe,
It took me about an hour to level the table with the palner head & set the feed rolls & the pressure bar. The Terminus gives a good cut. Happy so far.

[Dev Emch]

I have a very good dial indicator and fixtrue for planers. With my planer, I had to have the chipbreaker and pressure bar machined as they were not flat. Once that was done the bed rollers, chipbreaker, and pressure bar were not very difficult, maybe an hour. The knives on the other hand take me 3-4 hours to set. The the knives creep when you just touch the cutterhead. With the planer set this way it cuts wonderfully, but I end up waiting too long to change them. My process for milling wood is as follows:
1) Rough cut rough lumber to length and width
2) Surface one side on the jointer until flat
3) Use planer to surface other side and to plane to final thickness
4) Joint one edge
5) Cut to finished width and length

With the approach I get flat and straight wood, but it's tough on knives. I'm torn between a Terminus for the planer ( great finish, some tearout on figured woods, knives wear faster on rough wood), and a Byrd carbide spiral head. (great durability, but I'm uncertain of the quality of cut and flatness of the panel.

Joe... just wanted to make sure you got your decimel point in the right place. A standard starrett micrometer does not measure tenths. I had to special order mine from starrett for machining work. A dial indicator that measures tenths is called a super micrometer. For example, starrett makes one and it costs about $2500 bucks! Many digital micrometers carry a fourth significant figure; however, these guys should have their ummm fingers slapped. The hardware cannot indicate tenths. If you can maintain 1 thousandths over the length of a single knife, your doing good.

The terminus head and the byrd head for that matter both cannot beat the precision of an inplace knife grinder. For the luxury of snapping blades into place, you loose accuracy. Likewise, you loose accuracy with having to set all those inserts on a byrd head. The byrd head does do an excellent job on highly figured wood however.

The reason you cannot beat a knife grinder is that the big boys like oliver and buss used a honing stone to hone the blades after they were set. First you set the blades to within about 2 thousanths of an inch. 0.002 in. Then take a quick pass on each knife using the grinder head. Here, the cutter head is pin index locked while the grinder rides the fixture bar. Then turn on the planer and select the honing stone in place of the grinder. Now take a pass to the far end of the head and back again using a moderate feed rate. The honing stone hones the tops of each knife to the same height within tenths.

In a pro level shop not using exotics like teak or koa, you may need to regrind your knives about two or three times per year. With exotics, you will need to re-grind about every three months. In a hobby shop using domestic hardwoods, you will need to regrind about once every two or three years max!

As your blades begin to dull, they begin to burr over. So just like a good chef with his honing stick, you need to touch up the knives every once in a while. Here, you just turn on the planer and drive the honing stone to the far end of the head and back again and park it. Its that easy.

A set of in place honed knives will produce a type of chip like no other machine! They resemble the chip you get off a super fine tuned lie nielsen or norris A-4 hand plane. The words gossomer and fluffy have been used to describe these. And the finish is correspondingly smooth.

[Joe Jensen]

Unfortunately there is no grinder available for my Powermatic Model 100. I've considered upgrades in the past, found a nice PM 18" with grinder fresh rebuild for only $1800. But, I use my 3 car garage as a shop, and to part one car. The way the shop is layed out, I have to move the planer. Not sure I can move a "real" 18-24" planer by myself.

Also, I've read that jointed knives cut faster, but they are duller, so they beat the wood. The ground portion of the knive is parallel to the table, so the back side of the ground portion of the knife rubs the wood as it passes. Thoughts or comments?...joe

[Kyle Kraft]

Dev,

I picked up an Interapid dial test indicator which reads out in .0001" (one ten thousandth) and has an .018" (eighteen thousandth) travel a few years ago new for approximately $130 from J&L. I use it for precision setups in the machine shop routinely. Strap that baby on a surface gauge and away you go!

Kyle in K'zoo

[Joe Jensen]

I'm an engineer and have spent a lot of time with precision instruments. I don't recall where I bought it, but it is marked in .0002 increments. I paid about $400 for the indicator and mount about 20 years ago. the pressure bar on the new Powermatic had a .030 hump in the middle, and the chipbreaker was miss machined so that the two swing arms were at different angles. They sent me two more that were miss machined the same way. I gave up and paid on my own to have the chipbreaker remachined to make it right. Lots of effort, but the planer is sweet.


I'm longing for a 48" precision straight edge, but I just can't rationalize $200 for one just to check my jointer and table saw setup.

[Chris Rosenberger]

Unfortunately there is no grinder available for my Powermatic Model 100. I've considered upgrades in the past, found a nice PM 18" with grinder fresh rebuild for only $1800. But, I use my 3 car garage as a shop, and to part one car. The way the shop is layed out, I have to move the planer. Not sure I can move a "real" 18-24" planer by myself.

Joe I do not have any trouble moving my 18" planer by myself. :) I had to screw stops to the floor to keep it from moving when I do not want it to. Chris

[Dev Emch]

I'm an engineer and have spent a lot of time with precision instruments. I don't recall where I bought it, but it is marked in .0002 increments. I paid about $400 for the indicator and mount about 20 years ago. the pressure bar on the new Powermatic had a .030 hump in the middle, and the chipbreaker was miss machined so that the two swing arms were at different angles. They sent me two more that were miss machined the same way. I gave up and paid on my own to have the chipbreaker remachined to make it right. Lots of effort, but the planer is sweet.


I'm longing for a 48" precision straight edge, but I just can't rationalize $200 for one just to check my jointer and table saw setup.
For $200 bucks you will be lucky has heck to find a 48 inch camel back which is no longer in calibration! In calibration, these are in the thousands. It all depends on what your doing. For most machinery, this is not needed. On the other hand, if your turning up and dialing in say an oliver 166, you will need a camel back. You will also need a super precision machinist level as well! For wedge beds or table saws, this level of accuracy is not needed but a camel back sure makes setting up jointers easy. I just cannt get over the fact that you can hold tenths on your cutlery!!!! I am super impressed but years years of cutting metal on brown and sharpe milling machines and hardinge super precision lathes has really jaded me.

[Joe Jensen]

Dev, I really do get to +/- .0005 and it's a royal pain in the ass. The first time I may have spent more than a day on the 3 knives. Not only does each screw move the blade on either side, but they also moved the other blades. Lots of trial and error to "learn" how the gib screws moved the blades. Over the years I've improved, but it still takes more than 4 hours. I've never measured where they are after weeks of use, might have to do that before I put the new cutterhead in.

Have you ever checked how planer the the knives in cutterheads like Terminus or Tersa are?

[tod evans]

Dev, I really do get to +/- .0005 and it's a royal pain in the ass. The first time I may have spent more than a day on the 3 knives. Not only does each screw move the blade on either side, but they also moved the other blades. Lots of trial and error to "learn" how the gib screws moved the blades. Over the years I've improved, but it still takes more than 4 hours. I've never measured where they are after weeks of use, might have to do that before I put the new cutterhead in.

Have you ever checked how planer the the knives in cutterheads like Terminus or Tersa are?

joe, i use tersa but have no tools to measure .0000 i can goto .000 and in that range tersa is spot on every time.....02 tod

[Joe Jensen]

Dev, I saw some .0002" per foot straight edges listed for between $175 and $400. Starret was one supplier. Didn't think I needed more than that to check the jointer and table saw tables. Also, they had flat edges, bevel edges, and knife edges. Why would I want anything but a flat edge?

Are rentals available?

[Dev Emch]

Dev, I really do get to +/- .0005 and it's a royal pain in the ass. The first time I may have spent more than a day on the 3 knives. Not only does each screw move the blade on either side, but they also moved the other blades. Lots of trial and error to "learn" how the gib screws moved the blades. Over the years I've improved, but it still takes more than 4 hours. I've never measured where they are after weeks of use, might have to do that before I put the new cutterhead in.

Have you ever checked how planer the the knives in cutterheads like Terminus or Tersa are?

I have a terminus shaper head that has a 40 mm bore and stands about 6 inches tall. See my SMC post on my shaper....

http://www.sawmillcreek.org/showthread.php?t=19608&highlight=belated+gloat

I am quite pleased with how this thing works and I have used it to edge joint. Works great. But I have a knife grinder on my oliver planer and that planer will smoke the terminus head. Carefully dialed in, a 3 HSS knife oliver 299 can put a glass smooth surface on walnut burl with virtually no and I do mean NO blow out.

A buddy of mine had a tersa head in a jointer and he replaced it with a knife grinder equiped Oliver model #12 patternmaker jointer. This is a honed head sporting I recall three knives. Same deal. You could not give him the tersa head! The only head that works better is the ITCH head which he has in his oliver 299 planer. The planer is about WWII vintage but the factory retroed the head sometime during the 1970s. He also has the in place grinder to grind the ITCH inserts.

[Joe Jensen]

I have the Powermatic Model 100. No room for something bigger right now. Any way to grind the knives in that machine? I assume that after grinding a back bevel, the pressure bar needs to be reset to the new height of the planer blades.

I recall a woodworking textbook that showed grinding a heel on the jointer knives with a wetstone and the cutterhead running. Looked suicidal to me.

[Chris Rosenberger]

Joe I watched a cabinetmaker do that several years ago. He also saw it in a book. It looked very dangerous & the jointer cut worse after than it did before he did it.

[Phil Maddox]

Dev,

Wouldn't the diameter of the grinding wheel change as it went from one side of the knife to the other? I know we are talking insignificant amounts here but when we get down to these tolerances, wouldn't this be a factor?

Phil

[Dev Emch]

Dev,

Wouldn't the diameter of the grinding wheel change as it went from one side of the knife to the other? I know we are talking insignificant amounts here but when we get down to these tolerances, wouldn't this be a factor?

Phil

In theory it does. All grinding wheels are fryable. This is one reason a metal planer is more accurate than a blanchard grinder and why super high end german machines are still planed today.

Some of that difference is averaged out when you run the honing stone. But its more accurate than any knife setting scheme and its the only way your going to get all three or four knives to finish cut. That is why super high speed moulders use a stone honed cutter block or super precision insert heads that have a constant cutting circle.

Realisticly its more important that all three or four knives are at the same height. If one side of the cutter head has knives 1 or 2 thou higher than the other end, your going to taper cut your lumber. But this taper is, in practical terms, meaningless. And should it present a problem later on, there is always the wetzler rack.:D More importantly is how the other knives are cutting with respect to one another and here the honing stone earns its cookies for the day!