Justifying A Major Tool Purchase

[brent stanley]

Maybe not...

Hi Julie, I've seen many different discussions about the power issue but the results are all over the map. It's my feeling that it's semantics because it doesn't ever make any difference that anyone would actually notice. I swapped out a 3-knife for a Byrd head and even if there is a difference in power demands (and I personally have never measured) it didn't actually make any difference in the practical, real world.....and that's what matters. Any discussion about affects on power is marketing wank in my opinion.

[Julie Moriarty]

Hi Julie, I've seen many different discussions about the power issue but the results are all over the map. It's my feeling that it's semantics because it doesn't ever make any difference that anyone would actually notice. I swapped out a 3-knife for a Byrd head and even if there is a difference in power demands (and I personally have never measured) it didn't actually make any difference in the practical, real world.....and that's what matters. Any discussion about affects on power is marketing wank in my opinion.

Hi Brent,

When I first heard about helical cutter heads, my first thought regarding power consumption is that it would consume less power than straight knife heads. In my mind's eye I saw tiny cutters contacting the wood, compared to a long straight knife, as the reason for reduced power consumption.

Stumpy states the tiny fraction of a second between knife cuts gives the motor a free moment of rest and a chance to increase RPM. But once that knife hits the wood again, wouldn't that put a much greater load on the motor than a single insert? That seems a reasonable assumption.

One could argue the RPM of the head creates a load on the motor similar to several inserts chopping away at the wood simultaneously but it would never equal the load created by a single knife, at least not on wider stock.

When I was having issues with the DW735, I considered installing the Byrd head because I reasoned it would be easier on the motor and thus the planer would perform better. But, IIRC, there were some here who said after installing a helical head they had to take lighter passes because the theory Stumpy presented was in fact true. On the other hand, somewhere in the cobwebs of my mind, I think I remember someone taking an amp-meter to their planer before and after installing a helical head and the helical head drew less amps.

Yet the concern I hear most often about cutter heads is the time it takes to change knives vs. inserts. So it seems power consumption ranks, at best, second when choosing what cutter head one prefers. But probably much lower than that. The load a cutter head puts on the planer motor is only an issue when your planer is struggling to do the job you need it to do.

[brent stanley]

Hi Brent,

When I first heard about helical cutter heads, my first thought regarding power consumption is that it would consume less power than straight knife heads. In my mind's eye I saw tiny cutters contacting the wood, compared to a long straight knife, as the reason for reduced power consumption.

Stumpy states the tiny fraction of a second between knife cuts gives the motor a free moment of rest and a chance to increase RPM. But once that knife hits the wood again, wouldn't that put a much greater load on the motor than a single insert? That seems a reasonable assumption.

One could argue the RPM of the head creates a load on the motor similar to several inserts chopping away at the wood simultaneously but it would never equal the load created by a single knife, at least not on wider stock.

When I was having issues with the DW735, I considered installing the Byrd head because I reasoned it would be easier on the motor and thus the planer would perform better. But, IIRC, there were some here who said after installing a helical head they had to take lighter passes because the theory Stumpy presented was in fact true. On the other hand, somewhere in the cobwebs of my mind, I think I remember someone taking an amp-meter to their planer before and after installing a helical head and the helical head drew less amps.

Yet the concern I hear most often about cutter heads is the time it takes to change knives vs. inserts. So it seems power consumption ranks, at best, second when choosing what cutter head one prefers. But probably much lower than that. The load a cutter head puts on the planer motor is only an issue when your planer is struggling to do the job you need it to do.

Exactly....I think it would only ever matter if your machine was on the brink of not being able to do the job with straight knives....in which case you have other issues because you are using a poorly designed machine.

[Darcy Warner]

I will take the Hermance heads over any other insert type.

[Julie Moriarty]

Since the doctor said the baby delivery is due tomorrow I've been working on the finishing touches in the nursery. Sweeping, clearing the way, getting rid of 'Lil D's crib. We want little baby Hammer to feel right at home. It's been a looooong pregnancy.

[Darcy Warner]

It takes more effort to push a board over an insert type head compared to the same machine with straight knives.

I have done it, always same results.

There is always a knife in the wood with an insert head. You can feel the extra resistance.

[brent stanley]

It takes more effort to push a board over an insert type head compared to the same machine with straight knives.

I have done it, always same results.

There is always a knife in the wood with an insert head. You can feel the extra resistance.

That's the common explanation for it....I have some additional thoughts, but Felder claims their cutterhead which also would have a tooth permanently engaged uses less power.

[Darcy Warner]

That's the common explanation for it....I have some additional thoughts, but Felder claims their cutterhead which also would have a tooth permanently engaged uses less power.

All I know is that there is more resistance. Next time I swap a head I will have to put a clamp meter on it before an after. As Oliver, Whitney, Newman, Northfield developed their insert heads, the hp went up on their machines. Talking to Jeff at NF had the same experience as I have had.

[brent stanley]

All I know is that there is more resistance. Next time I swap a head I will have to put a clamp meter on it before an after. As Oliver, Whitney, Newman, Northfield developed their insert heads, the hp went up on their machines. Talking to Jeff at NF had the same experience as I have had.

The side by side comparison (and before/after) with ammeters has been done and some have shown a greater current draw with the spiral or helical head but as I recall It's quite small and I can't say it added up to enough for me to give a crap with my 8" jointer. If you're hand feeding a 26" jointer at full capacity then the difference could add up to a lot. What I'm curious about is how Felder managed to build a helical insert head where the power use goes DOWN....

B

[Greg Parrish]

With my prior DW735, I would trip the 15amp breaker on the retractable 12 gauge extension cord reel if I used that for power. The straight blades never did but a wide, hard board with the shelix head would trip it and bog to a stop. Was a pain for sure.

[brent stanley]

With my prior DW735, I would trip the 15amp breaker on the retractable 12 gauge extension cord reel if I used that for power. The straight blades never did but a wide, hard board with the shelix head would trip it and bog to a stop. Was a pain for sure.

Regardless of the cut depth? Or only if you tried to take too much?

[Greg Parrish]

Regardless of the cut depth? Or only if you tried to take too much?

well, certainly with a deeper cut, but I’m implying that for similar cuts I would get more circuit trips from the shelix head than the straight blade. Not sure if it’s the energy difference required to scrape vs cut, or the microsecond gap between blades vs continuous cutting, or something else. Was just something I noticed. Was worth the hassle though to get better results in tougher, figured woods.

Most times I ran it on a 20amp circuit which helped limit issues though but even then the motor was limited compared to the floor machines. I was always worried about burning up the machine but I’m sure there are folks that beat these things to death in the field doing their work and gets years of service.

[Van Huskey]

What I'm curious about is how Felder managed to build a helical insert head where the power use goes DOWN....

B

I bet it is related to the low number of spirals they use. The Hammer heads only have two.

[brent stanley]

I bet it is related to the low number of spirals they use. The Hammer heads only have two.

Ahhh....right. I keep forgetting that.

B

[Jared Sankovich]

The power requirements of helical insert heads seem to parallel motorsports engineering (big bang firing order)