Looking for advice on spiral cutterhead.

[Gustav Gabor]

After tuning up my 12" jointer (old Taiwanese CKM model, but quite well made) the time has come to replace the 3 knife cutterhead (98mm) with a spiral insert head.
I just don't want to have to set and adjust jointer or planer knives ever again! I'm done with that.... too old and lazy, I guess....

I've come across a company called Sheartak, who like Byrd offers spiral cutterheads with the same 30 degree shear angle. Cutterhead looks identical to the Byrd.
Sheartak is made in China, however the prices are 30% cheaper than Byrd.
So far the few reviews I've seen are very positive. (on the "bay")

The Sheartak standard insert measures 15 x 15 x 2.5 x 150mm radius, whereas the Byrd is 15 x 15 x 2.5 but with a 100mm radius.
Perhaps the Sheartak would have slightly less "grooving" than Byrd inserts?

I'm also thinking of replacing the 4 knife cutterhead (120mm) in my Griggio 24" planer, but that's pretty big money, especially with Byrd.

My dilemma is that Sheartak offers the 12" CKM cutterhead with either 6 rows and 80 inserts, or 8 rows and 96 inserts (same as the Byrd)
Their Griggio PSA630 cutterhead is available in a 6 row with 162 inserts, or 9 row with 234 inserts. (would have to be custom made through Byrd, or Hermance)

Of course, the more inserts, the more money....

All that, just to ask the simple question(s) ..........

Is it better to have more cutting inserts? Would the cut quality be at all noticeably better?
Any downsides to having more inserts? (Besides the obvious initial cost, and the time and money involved in replacing more inserts at some point in the future.)

I installed a Byrd cutterhead in my little 13" Delta lunch box planer 3 years ago, and it works really well, but does leave very minor grooving/tracks on the surface. Nothing that can't be taken
care of easily with a few passes of any decent sander. So much better on figured wood though!

Mike from Sheartak sent me this pic of a rather large cutterhead they made..... 2100mm (about 82 5/8") cutting length..... huuuge!!
It is a spiral cutterhead, but this one doesn't have the shear angle, like what I'm after.

[joe milana]

An insert with a straight edge cant be set at a shear angle unless it is ground in place. Then you have an insert with a radius edge. That's why the byrd inserts are radiused.

[Gustav Gabor]

I think you may have missed where I mentioned that the Sheartak does in fact have a radius on the edge. It's a 150mm radius vs the 100mm on the Byrd.

An insert with a straight edge cant be set at a shear angle unless it is ground in place. Then you have an insert with a radius edge. That's why the byrd inserts are radiused.

[Derek Cohen]

Gustav, assuming that you will use a thicknesser/planer after the jointer, there is not much point in seeking an ultra fine finish on the jointer. I'd get the head with the fewer inserts. Carbide inserts last a long time, and a shear cut leaves a very decent finish.

Regards from Perth

Derek

[joe milana]

Correct, I misread. Fewer rows of cutters will give less feed pressure. Not necessarily a good thing unless the machine is underpowered. Perched tooth cutterheads have depth and feed rate limitations for safety reasons. The larger radius cutter might look good on paper, but a side by side comparison would be necessary. The smaller radius allows a bit more machining tolerance without leaving visible irregularities in the wood. Again, mostly in theory. You'll likely be happy with the upgrade.

[David Kumm]

Although I'd keep the knives on the jointer, I'd prefer the large diameter, less inserts for a spiral head for a jointer. I feel better about less distance between the head and the lips of the tables. Planer with a big motor favors the additional inserts and the perched vs inset design is irrelevant. Dave

[Gustav Gabor]

Thank you for the replies! All very solid advice and reasoning.

For the jointer, the only reason I might be after a better finish would be for edge joints that would get glued directly after coming off the machine.

By the way, this 12" jointer only has a 3hp motor, so not a lot of power to spare.

I wonder if having more inserts would make the grooving effect less noticeable. In that little lunch box planer with only about 40 inserts over 13", the grooves can be seen if held up to a light, although I'm sure they're less than .001 in depth. Then again, would having an extra 16 inserts on the cutterhead make that much of a difference?? Decisions, decisions.......

Come to think of it, I've never tried to see if the planed edge off the Byrd cutterhead in that small planer would be good enough for an invisible edge joint. So far, I've only used it to thickness stock, not for edge jointing.
Perhaps it's time to try it and find out.....

[Justin Godar]

Did you try the Sheartak head? I'm considering buying one and I'd like to hear a first hand review.

I'd use it for making edge joints and I haven't always been impressed with spiral cutterheads because the grooving can cause visible glue lines and (possibly) bad joints. I'm hoping that the larger edge radius and higher number of cutters would reduce grooving too.

[Gustav Gabor]

Well, I ended up buying the 80 insert Sheartak cutter head after all, and coincidentally just installed it yesterday on my 34 year old Taiwanese CKM jointer.

Well, mostly installed, as I have to have a custom washer made to complete the install to retain the pulley.

This particular cutter head is a "generic" 12" model that's made for many different Taiwanese and Chinese jointers, including the 12" Powermatic, which tend to be much newer than my old beast.
While all the important dimensions are the same, my old 3 knife cutter head had a different bearing retaining system than the new one. The old one had both ends of the shaft externally threaded to accept a locking castle nut type of retainer, whereas the new cutter head has the shafts drilled and internally threaded to accept left hand threaded metric bolts.

I believe this would be a direct fit for newer jointers though.....

I did a lot of homework and asked for dimensional drawings before I bought it to make sure I can make it work.

The quality of the Sheartak cutter head is excellent. Most definitely on par with Byrd. (I have a Byrd cutter head in my small planer)

I installed new SKF bearings (took 2 bearings per side), and it fit perfectly into the jointer.

As to the cut quality, I will have to wait until I get that washer back from my machinist friend to find out, but at this point I'm very optimistic.
So far, I'm very happy with it. The fact that I saved nearly 50% over a similar Byrd unit .....

The new Sheartak cutter head:



The old 3 knife cutter head:



The gaping hole where the cutter head belongs:

[Vlad Mandelbloom]

Well, I ended up buying the 80 insert Sheartak cutter head after all, and coincidentally just installed it yesterday on my 34 year old Taiwanese CKM jointer.

Well, mostly installed, as I have to have a custom washer made to complete the install to retain the pulley.

This particular cutter head is a "generic" 12" model that's made for many different Taiwanese and Chinese jointers, including the 12" Powermatic, which tend to be much newer than my old beast.
While all the important dimensions are the same, my old 3 knife cutter head had a different bearing retaining system than the new one. The old one had both ends of the shaft externally threaded to accept a locking castle nut type of retainer, whereas the new cutter head has the shafts drilled and internally threaded to accept left hand threaded metric bolts.

I believe this would be a direct fit for newer jointers though.....

I did a lot of homework and asked for dimensional drawings before I bought it to make sure I can make it work.

The quality of the Sheartak cutter head is excellent. Most definitely on par with Byrd. (I have a Byrd cutter head in my small planer)

I installed new SKF bearings (took 2 bearings per side), and it fit perfectly into the jointer.

As to the cut quality, I will have to wait until I get that washer back from my machinist friend to find out, but at this point I'm very optimistic.
So far, I'm very happy with it. The fact that I saved nearly 50% over a similar Byrd unit .....

Hi Gustav, what's the verdict here?

I'm looking to purchase a cutter head for my 20" planer. Byrd's head has 100 inserts at a cost of about $1,000 where Sheartak has 132 inserts at about $1,200.

Wondering if its worth the extra $$?

Also heard somewhere that you can buy Sheartak directly from the manufacturer for a lot less. Does anyone have a link to their site? Only thing i can find is a Canadian middleman/distributor.

Thanks,

[Gustav Gabor]

The cutter head works great!
Cut quality is excellent, and the jointer is now very quiet.
Almost too quiet!
A few times I forgot that I left the machine running, as I didn't hear it over the dust collector noise.
I haven't had to rotate the cutters yet, the inserts seem to be holding up well.
I'm surprised that the Sheartak costs more than the Byrd. Their prices were noticeably lower in the past, mind you it IS 132 inserts vs 100, so that's likely why the higher cost.
I think more inserts would give a slightly better cut quality, but will never be as smooth (flat) as a very sharp straight blade cutter head. Having said that, the ability to plane/joint figured material in either direction far outweighs the straight knives, in my opinion.
I think Alibaba has cutter heads like these for less money, but watch the shipping costs, as these things are HEAVY!! I didn't want to take a chance on Alibaba.
All in all, one of the better decisions I made in my shop. No more setting straight knives and super quiet = priceless!!