Freeborn vs Garniga insert

[Jeff Roltgen]

is the Freeborn insert the same as their brazed, run cope and stick face down?

Yes. And as Jared pointed out (and you probably figured out already), you can invert/swap feed directions and shaper rotation if face-up processing is desired.

jeff

[Phillip Mitchell]

Joe, can you explain this further? Do you need cnc positioning or dro's to exploit this type of tooling effectively? Is there something inherent in a straight knife planer that disqualifies it?

Not Joe, but I can imagine that the variation possible with setting straight knives in a cutterhead and the potential for less than a perfectly parallel knives to planer bed relationship introduces “error/variable thicknesses” into the S4S process and how those thickness variations can be amplified in error when flipping stock and not just working from a single reference face.

I have struggled with this a bit before in the past and noticed that planer knives were off parallel enough over 20” to cause an issue sometimes with referencing off both sides. Took me a minute to figure out what was going on the first time I noticed it.

[Warren Lake]

you can set up your machine better. Ive never bothered but do set up the cutting circle bang on. If I want better then its going to be adjusting the planer table up on one side. You can run your rail and style material on the same side of your machine for more consistent.

[Phillip Mitchell]

Warren, I am aware of that. The machine is currently setup very well / parallel. It was only the first time I reset the knives and used the OEM aluminum knife setting jig where I got the out of parallel results with the knives. I learned a few things from that...one of them being that I couldn’t trust that knife setting jig and it had likely been bent/damaged over the years. Didn’t feel like typing everything out at once, but should have clarified a bit.

I could be wrong, but I was just speculating on what Joe was mentioning based on my own results early on.

[Kevin Jenness]

Not Joe, but I can imagine that the variation possible with setting straight knives in a cutterhead and the potential for less than a perfectly parallel knives to planer bed relationship introduces “error/variable thicknesses” into the S4S process and how those thickness variations can be amplified in error when flipping stock and not just working from a single reference face.

I have struggled with this a bit before in the past and noticed that planer knives were off parallel enough over 20” to cause an issue sometimes with referencing off both sides. Took me a minute to figure out what was going on the first time I noticed it.

I see your point. I have a knife grinder on my planer and the side to side results are within a few thousandths, but I still prefer to register all joinery operations from one face for simplicity and to force any variations to the opposite face. When I start flipping pieces over my small brain can get confused, so I keep the witness marks visible. The practice is particularly helpful when I am forced to remake a part whose thickness may be off slightly from the rest. As Jeff points out, I will reverse the cutter rotation and orientation if necessary to achieve this.

I used to work with a SCMI S52 that had one of those aluminum setting gauges. The knives may have been parallel to the cutterhead but the table was not quite, and the central column did not lend itself to making it so. The onboard grinder was more nearly parallel to the bed so gradually the side to side results evened out until the knives were reset. The guy who maintained the machine just settled for using the jig and we had to deal with the results. It wasn't off by much but working off one face for stick, cope and mortising for spline tenons ensured consistent assemblies.

[Warren Lake]

I tried one gauge once and maybe I didnt get it, it wasnt even close. I have the SCM aluminum things and never tried them.

Dial I do .0005 accuracy and that cant be achieved without tapping, in other words im coaxing them to assimilate. Head is my reference, knife projection above is .050. This will changed as knives wear no matter what knife system you have. To put level of accuracy in context I emailed Tersa once and they quoted me .0004 accuracy if I remember correctly and id say likely they set the bar.

[Steve Rozmiarek]

Thought just crossed my mind, relating planer knives to insert shaper tooling, how accurate can you realistically expect the inserts to index? I can see an argument that a brazed cutter could theoretically have tighter tolerances.

[Jeff Roltgen]

how accurate can you realistically expect the inserts to index?

Uh-oh. Another can of worms has been opened...

You certainly are thinking right. Seems insert shaper heads would be much easier to mis-align, especially when compared to carbide inserts on a helical planer cutter head. We've all seen plenty of posts about getting those darn things cleaned and seated properly, yet still, the witness lines can remain...

Which brings us to the point I think most of us have also heard discussed - only one blade of the 2-4 on any given router bit or shaper cutter is making 100% full contact and creating the final profile. Others are there to assist, but as much for balance, just don't expect them all to be cutting precisely the same amount. One is doing 100%, the others are along for the ride, making a profile something like 98-99% of the one who protrudes the most. As an illustration, next time you run any spinning bit, especially a brazed carbide, take a close look at each individual knife when you're done. You'll likely see one cutter has a bit more pitch and dust build up than the others = it's the one making the absolute final shape, when you start measuring in the single digit thousandths. Not advocating sloppy knife seating, but that a certain level of looseness does exist no matter how much we fuss over setups, and that's okay. We can still enjoy excellent results.

Think of all the successes you've had using your existing tooling before we started sweating all these details.
Now realize, no matter which of the great cutters you choose here, I think most of us agree, it really is almost guaranteed to be even better!

jeff

[Phillip Mitchell]

I used to work with a SCMI S52 that had one of those aluminum setting gauges. The knives may have been parallel to the cutterhead but the table was not quite, and the central column did not lend itself to making it so. The onboard grinder was more nearly parallel to the bed so gradually the side to side results evened out until the knives were reset. The guy who maintained the machine just settled for using the jig and we had to deal with the results. It wasn't off by much but working off one face for stick, cope and mortising for spline tenons ensured consistent assemblies.

Yes...hits close to home. Not sure if you remember or not but I’ve had a slightly older SCM S50 for a few years now and it has the same “flaw” inherent in the design. I have managed to get the knives set parallel to the table but not by using the OEM aluminum jig; I do think that my jig has suffered some damaged and is no longer useful unless I want to try and flatten it.

I guess I am fortunate that I am getting parallel results currently with the bed of such a design - the large diameter central column that doesn’t really allow for 4 corner adjustment. The most recent method I have used for knife setting is a pair of Panhans magnetic knife setting gauges that I found used on eBay at some point.

https://www.scosarg.com/panhans-1533...setting-gauges

I have an onboard grinder on mine as well but it does not seem to have the precision of adjustment that I’d hoped...or, put another way, I have yet to find the sweet spot for progressively deeper passes when trying to lightly grind the knives for a quick touch up. Always seems to drop too much like there is some type of backlash in the lowering mechanism which is frustrating and not very repeatable.

My only “long term” irritation/desire with the planer is that I wish it had a Tersa head it in.

[Warren Lake]

some employees work harder than others. You will tell by who has the most pitch on them.

Good point Phillip on the center column not being the best. Likely it can be shimmed if out. Crucial stuff run in the middle. Ive never tested if the height lock makes a difference but I use it anyway. The other planer I have not fired up table is adjustable and rides on two posts instead of the one.

On the shaper on old heads i can adjust in and out of the knife. Then is the shaft true, what is the clearance in the head as it slides over the shaft and is the shaft 90 degrees to the table.

[Joe Calhoon]

Joe, can you explain this further? Do you need cnc positioning or dro's to exploit this type of tooling effectively? Is there something inherent in a straight knife planer that disqualifies it?

Kevin, no you don’t need CNC to run this set. Just a fussy set up flipping the pieces on a old school shaper, especially if you have to go back and fourth between the cuts. I have run it on my vintage T23. Just a lot more setup. On a shaper like this a easier setup would be separate cope and stick cutters that register the same for fence and shaft serttings.
The planer issue is if you have any thickness variation side to side this will also cause misalignment that will be magnified by the flipping. This can be dealt with also but just makes things harder.

I ran a straight knife SCM planer for 20 years and certainly got by but when we went to all Tersa heads on the planer, jointer and S4Smachine it was a huge difference in the precision and quality of our joinery. The nice thing is you can come back to repeat thickness and width without any fussing. I’m sure the same fo spiral head planing on quality machines. We used to run everything face down as many here mentioned. But now run everything face up with very little variation on either face. Wood is wood and I only try to achieve accuracy to within 0.1 or 0.2mm. Getting this accurate on your S4S just makes all following operations easier.

[Joe Calhoon]

Thought just crossed my mind, relating planer knives to insert shaper tooling, how accurate can you realistically expect the inserts to index? I can see an argument that a brazed cutter could theoretically have tighter tolerances.

Steve, never a problem registering my Tersa planer knives. It’s a pretty fool proof setup.
shaper inserts can certainly have alignment issues though and you just have to use a little care when changing or flipping knives. Manufacturers have patented holding and registering systems with some better than others but all I have used are workable. You can usually visually look at a insert cutter to see if a knife is off slightly. Narrow knives that register against one edge and and a hole can easily get twisted slightly. Usually shows up in the cut. It’s just a feel you get after a little time on inserts to make sure they are right.

Braised carbide probably is closer since ground on the head but the sharpness and tool geometry of the inserts makes for better cuts. I still use a lot of braised tooling. It all has its place.

[J.R. Rutter]

do you buy through a dealer or direct?

I bought direct. Unique sells their heads, too.

[brent stanley]

Thanks for this, it can be a can of worms indeed! Makes things like chip loading calculations hard or controversial.

The manufacturers use different approaches to securing the tips in the block, and most of the big name manufacturers are pretty good but none are really bomb proof, so care and even double checking on a setting stand might be a good idea if you're having problems with fit. That said, I haven't ever personally had to for the insert heads.

A friend and I were talking just a couple of days ago about how often we seem to get a two knife cut with our limiter heads and it was more than half the time which is surprising. Quality blocks and quality grinding make a big difference of course. We also compared a Z2 shear, to a Z4 dual shear to a spiral block in the same piece of wood at moderate feed rates and flipping the piece and the Z4 always performed better. New knives in all. If it was only taking a 1 knife cut, the other three wouldn't have made any difference but they seemed to so it seems to me it would be most accurate to say there will almost always be one knife doing the most work, but in a well tuned block, the other knives are helping and reduce the chip size associated with that one knife which can translate into cut quality. It was a fun little experiment.

Uh-oh. Another can of worms has been opened...

You certainly are thinking right. Seems insert shaper heads would be much easier to mis-align, especially when compared to carbide inserts on a helical planer cutter head. We've all seen plenty of posts about getting those darn things cleaned and seated properly, yet still, the witness lines can remain...

Which brings us to the point I think most of us have also heard discussed - only one blade of the 2-4 on any given router bit or shaper cutter is making 100% full contact and creating the final profile. Others are there to assist, but as much for balance, just don't expect them all to be cutting precisely the same amount. One is doing 100%, the others are along for the ride, making a profile something like 98-99% of the one who protrudes the most. As an illustration, next time you run any spinning bit, especially a brazed carbide, take a close look at each individual knife when you're done. You'll likely see one cutter has a bit more pitch and dust build up than the others = it's the one making the absolute final shape, when you start measuring in the single digit thousandths. Not advocating sloppy knife seating, but that a certain level of looseness does exist no matter how much we fuss over setups, and that's okay. We can still enjoy excellent results.

Think of all the successes you've had using your existing tooling before we started sweating all these details.
Now realize, no matter which of the great cutters you choose here, I think most of us agree, it really is almost guaranteed to be even better!

jeff

[Warren Lake]

Phillip have you ever used the knife grinder then put a dial on and gone side to side measuring off you head to the tip pf the knife to see what you get? not having a machine past with a knife grinder do have one waiting till I have the time.

I did look at the knife set up and knives are pretty sharp little use on them and little pitch but if an onboard grinder was used its useless. Im guessing the knives were sent out and had a pro grind then the knives put in by a moron. Its off the map 10 times worse than any set up ive ever seen machine. It came from a school and Id call it unusable as set up. You could not even set the stuff below the cutter head as the cutting circle is so far out of whack.

I was told the knife grinder was gone but after my usual Colombo persistence its sitting with the machine. Later told by a higher up there up the grinder wasnt in the ad. Told him your teacher told me it was gone. You would have found it then to scrap, a part of a machine with history. Nice respect you have for machinery, second how you respect our tax dollars.

Phillip if you do run the grinder sometime or someone else uses one tell me what type of tolerance you can expect. If it was really bang on it would be a good thing. I can set knives very accurate on my SCM stuff but there are a few reasons. On a wider planer and wider knives id think it gets harder. I can tap my knives under load to get them close to bang on. A thicker knife but mostly wider id think gets harder to do that.

Ive asked Tersa before and think I listed it here and the stated tolerances were very impressive.