Thread: Shellix Head Question

A very logical question Chris, and one I will have a go at answering....

I would expext that by the time the TC blade is blunt enough to warrant rotation that it would not have lost much, if anything, in thickness. Someone with better knowledge will be able to comment with more accuracy, but I have a suspicion that the wear is actually on the bevel of the TC edge, and therefore doesn't effect the thickness (and therefore the registration with the others).

Think about it in terms of a handplane blade or chisel - you only flatten the back once. To get them sharp again you just recede the bevel back, not the back. In the case of the handplane blade (which approaches the timber in exactly the same way is the TC blade on the thicky) the back of the blade doesn't get worn down.

Waiddaminit, I think I need to think a bit more....because the length of the blade will affect how high it projects.....UNLESS it's dead horizontal when it strikes the wood. In that case it matters not about the blade length and so no wuckas with registration.

Think I better go and inspect my head. I'll have a look at the thicknesser while I'm there too....

Just as well I checked. The blade strikes the timber when it is still on an angle pointing upwards (about 5-10°). The second blade over was horizontal AFTER it had passed the cutting point.

That is to say that the blade edge was level with the outfeed table when it was still at 5-10° pointing upwards.

So I'll just stick with the first part of my answer - when it blunt enough to warrant rotating it probably won't have worn down enough to make any discernible difference. I need to do some jointing tomorrow, so hopefully I'll remember to rotate one blade and see if it leaves a deeper groove about 15mm wide. Given that my blades have now been over many kilometres of timber (most of it nasty hardwood) without having done the first rotation, it may give a clue. So far I have only rotated one blade, and that was right after I bought it - the blade had a micro-nick in it right from purchase. I could barely see it and it took some finding, but it was leaving a raised ridge on the boards.

Using Andy's thicky recently (for Pac Man's timber) it sounded different to mine which gave me a clue that mine may need rotating. The surface from his may have been a little bit smoother, but I didn't take as much note of that as I should have. Mind you, his motor sounded marginally different too (at idle).


EDIT: more thinking.......the blade gets it's registration from the bevel that is opposite the cutting bevel, as it rests against the roller/head/thingy. That being the case, I think that adds weight to my argument about not receding enough to make any difference - otherwise if the edges were about half way through their service life and you hit a nail, the new edge would definitely leave a groove. Surely that's not the case.

I think it's a case of the bit loosing it's edge over wearing down....
The hardness of the bit shouldn't allow the sort of wear you are questioning...
Just my thoughts...
May I encourage you to ring or email the local Australian agent,
they were extremely helpful when I bought my Byre Shellix Cutter Head for my Dewalt 735..
[one thing to confess...the original Dewalt 3 blades haven't yet dulled enough for the change over]
Cheers, crowie

Originally Posted by crowie

[one thing to confess...the original Dewalt 3 blades haven't yet dulled enough for the change over]
Cheers, crowie

Well you'd better start making a ton of toys then.

I will ring Byrd in the US tonight and ask them but I thought someone here might have first hand experience. Brett's experience of locating the nicked segment was another thing that had occurred to me as a problem with the segmented head. Brett, I can't see why they would need rotating on your machine, surely they last longer than that though the American timbers are a lot softer than ours and they would have the most miles on this style of head. I think the Minimax is ahead on points at the moment though Felder offered me a good deal with a really nice discount.

Hi Chris

I cannot answer the question about blade height - it will be some time before I change the squares on my A3-31 Shellix head. There was another reason why I chose the Hammer over the Minimax. This was the noise level. The Shellix head is incredibly quiet! Noise is no longer a concern - for my family, the neighbours, and my ears.

Regards from Perth

Derek

Derek, yes the Tersa head is always going to be more noisy though not as noisy as the cheaper units with higher profile blades. Noise to me is not an issue as my workshop is fairly isolated and I would always use ear defenders no matter what the machine.

Originally Posted by derekcohen

This was the noise level.

Yeah, there is that. Nobody has ever rushed to put their fingers in their ears in my shed - and there have been a fair few witness the operation.

More compact dust chips (a typical bag of hardwood dust is about 18kgs - dunno how that compares to conventional blades though).

Nice rattling sound as they zoom through the hose. Mmmmm.

I tell ya, you'll regret not havng a spiral head (on either machine). Spirals already outsell Tersa on Felder/Hammer. Time will come when it'll cost more to get conventional blades because they make so few of them, and it wouldn't surprise me if that's by 2020.

That will also affect resale value, and resaleability when your old and decrepit (also by 2020? ).

Remember how long that Hammer up in Cessnock was for sale.......
Remember the price dropping......
Remember how quickly your Powermatic with spiral head sold, and for the asking price?

I can tell you definitively that rotating the tips on a Shelix head makes no difference at all to the cutting circle.
Also, because the inserts are ground with a radius rather than square, there are no sharp lines left in the timber; if you have a line, the insert has something under it and isn't seated properly.

As for the noise, changing our 24" thicknesser to Shelix from a 4-knife straight block knocked 11dB off.

All I can say is: Do it.

My experience has only been with DeWalt Dw1150 & Electra Beckum 10 x 6" and Kity 638 12 x 9" machines, which I've used for about 40 years. I cannot give you feedback on helical or angled head multi-cutter machines.

Having said that however, I've noticed great differences between the cutting characteristics of steel & wolfram blades. I've used both in all machines, and have found that HSS gives a far cleaner finish in timber when fresh. The edge goes more rapidly in steel of course, and it's immediately noticeable. But when new and on clean timber it's the best edge for finishing cuts.

Wolfram carbide is hard, and by its very nature brittle. It is usually presented with a significantly coarser sharpening angle to counter its brittle nature, with more "meat" available behind the cutting edge. As such it's useful for dusty timber, or initial dressing of air dried timber. The longer lasting edges tend to slowly dull rather than go off rapidly like steel, and the machines just seem to have an increasingly hard time traversing heavily knotted timber, especially going "with" the grain.

Close examination of the used edges of both types of blades reveals that there's little if any loss of material (but evidence of microscopic rounding) from the edge of the harder blades, whereas steel has a fairly noticeable loss of edge material when viewed through a magnifying loupe.

Some have suggested when refreshing the blades in helical heads to turn the faces of only every other blade (they're numbered so you can keep track) to give an almost "as new" finish and performance with significantly longer overall blade life. This and my own experience of the dulling characteristics of carbide lends credence to the thesis that partial exchange of cutting edges on helical headed machines won't be noticeable on the finished face of timber.

Given my own experience, I'd have to say that both steel and TCT blades have their relative merits, but that helical cutterheads just seem to be another quantum ahead again in overall superiority. Maybe it's time to start saving for a Hammer myself....

Originally Posted by derekcohen

Hi Chris

I cannot answer the question about blade height - it will be some time before I change the squares on my A3-31 Shellix head. There was another reason why I chose the Hammer over the Minimax. This was the noise level. The Shellix head is incredibly quiet! Noise is no longer a concern - for my family, the neighbours, and my ears.

Regards from Perth

Derek

I have to agree here, I upgraded froma standard blade 6" Carbatech jointer to a Hammer C3 31 combo with Silent power helical head and i coudlnt believe it. while i was using it i can talk to people and hear them no different if the machines running or not, my 1yr old son sleeps not far away from the garage and never woke him at 9pm at night thicknessing timber. I have rotated one head on my blade and havent noticed a difference in the finish once passed through.

Cannot speak on behalf of the other terse blades as ive never owned them but im glad i have a set of 10 extra little cutters with 4 sides of cutters per little square blade, will last me a long long time

Originally Posted by Ratbag

Some have suggested when refreshing the blades in helical heads to turn the faces of only every other blade (they're numbered so you can keep track) to give an almost "as new" finish and performance with significantly longer overall blade life. This and my own experience of the dulling characteristics of carbide lends credence to the thesis that partial exchange of cutting edges on helical headed machines won't be noticeable on the finished face of timber.

We rotate every second row at work and the finish is about 80-90%