Spiral block

[Doug B]

After reading a recent thread on spiral blocks I thought I'd share a few photos I took recently whilst planing up some timber on my Hammer thicknesser fitted with a spiral block, hopefully this will address a few of the questions raised in that thread & it will be of interest to a few of you.
This is the block in question

I mainly plane pine & some Oak, this is the build up of resin around the extraction outlet above the block since the last maintenance of the thicknesser which included cleaning any resin off the block & surrounding surfaces

& this is the build up of resin under each tip, as you can see compared with the amount of build up elsewhere there is little build up in the gullets

My surface planer is a 1950's Wadkin, with its two blades set at a slight angle across the length of the block, the finish this leaves is comparable to a four knife Felder block I also use, though the blades in that are set straight in line with the block as per most standard blocks.
This is the typical finish the Wadkin leaves

This next photo shows the same area of Walnut after it has been passed through the thicknesser removing a 1mm cut

At the same time as I was running out the Walnut I also dimensioned some Pine, this is the finish on that again straight off the spiral block

The finish I get off the spiral block is by far the best I've got off any block I've used & whilst I've not made records of the longevity of the tips, these tips have out last two changes of blades in my surface planer & are still giving a very satisfactory finish & look like they will easily see off at least another set of standard blades.
Whilst clearly a tersa block will be far quicker to change blades in than replacing tips, the time between turning the tips & replacing blades will be longer.
In short I'm very happy with the spiral block, the finish is first rate & I'd definitely buy another, whether the extra initial expense is justifiable can only really be determined by the individual or business investing in the block, but I think it was worth it.

 

[scosarg]

It looks like 15mm radiused knives in the Felder planer block -
If you need to buy a quantity, let me know - probably a lot cheaper than felder
http://scosarg.com/l-15-w-15-t-2-5-d-6-2-r-150

 

[No skills]

Shame these blocks aren't more affordable, a spiral block in a lunchbox thicknesser would most likely do my dimensioning for life.
One of life's first world problems I spose.

 

[doctor Bob]

Thanks Doug, great pics.
I really think it's horses for courses on the best block. Certainly it's between spiral or tersa (or similar system). As a commercial enterprise I have got very used to the tersa system and for the shear speed of changing blades on a 4 sider I believe it's a good system for me. The finish is on a par with yours, however even if it loses it's edge after a while it doesn't really matter as everything goes through the speed sander as well.
I suspect noise is much better with your system, tersa are incredibly quiet initially but as they dull the noise increases, it's a good indicator of a blade change.

 

[Doug B]

I ran about a cubic meter of chestnut through Jonnys four sider on Friday Bob, definitely needed the ear defenders but an awesome piece of kit & with Tersa blocks I couldnt imagine a much better machine for PAR production, though I doubt my neighbours would like the noise or workshop extension I'd need to fit one in

 

[custard]

I was in another maker's workshop last week who has recently got a new Felder with the spiral block (I'm on the previous generation with the Felder system four knife block). He's over the moon, and understandably so, we both use lots of highly figured timber, but after planing he's all done, where as I have often to then put my timber through a drum sander to remove the traces of tear out. One issue he did raise which was new to me though, he said he's struggling to edge plane thinner timbers square with his spiral planer, apparently the spiral layout tries to twist the workpiece and it's difficult to keep it firm against the fence. Maybe the best solution of all is a planer with a traditional straight disposable knife system, and a thicknesser with a spiral block.

 

[Doug B]

Maybe the best solution of all is a planer with a traditional straight disposable knife system, and a thicknesser with a spiral block.

Fortunately that's the set up I have in my own workshop custard, I regularly work in other workshops that have combined planer thicknessers but do prefer the separates solution.
Though a four sider would be nice :-k

 

[scosarg]

I have checked about the Felder knives - apparently they have Patented the size for their cutter blocks [13.8mm] so sadly you currently have to buy the knives from them..I am not sure if it is a genuine Patent or just Pat pending.

 

[Doug B]

I have checked about the Felder knives - apparently they have Patented the size for their cutter blocks [13.8mm] so sadly you currently have to buy the knives from them..I am not sure if it is a genuine Patent or just Pat pending.

I had already been told this but it wasn't anything I didn't expect, it is Felder we are talking about :-"

 

[timbly]

Hi
Our experience with the spiral block in a new A3 41 back in 2014 wasn’t very positive - pronounced scallop lines running the length of the board as evidenced in this thread ( http://www.woodworkuk.co.uk/forum/viewtopic.php?f=6&t=9594&hilit=hammer ). Given everyone else’s rave reviews I guess we were unlucky with our machine although a separate identical machine tested up at Felder HQ gave only somewhat better results.. The Tersa style Hammer replacement is excellent but a lot noisier. Now we have a wide belt to run stock through we may well dip our toes back into the world of the spiral block in the future..
Tim

 

[tomatwark]

Thanks Doug, great pics.
I really think it's horses for courses on the best block. Certainly it's between spiral or tersa (or similar system). As a commercial enterprise I have got very used to the tersa system and for the shear speed of changing blades on a 4 sider I believe it's a good system for me. The finish is on a par with yours, however even if it loses it's edge after a while it doesn't really matter as everything goes through the speed sander as well.
I suspect noise is much better with your system, tersa are incredibly quiet initially but as they dull the noise increases, it's a good indicator of a blade change.

Like you Bob I like the tersa blocks on my 4 sider but have just got a price for changing the vertical heads to spiral, as we tend to plan mostly 20mm to 40mm thick section we only use a small bit of the knife and my thinking is that at least with a spiral block in those 2 heads I can move the cutters around in the block.

There is nothing more annoying than the hidden staple in the edge of the board.

 

[doctor Bob]

Thanks Doug, great pics.
I really think it's horses for courses on the best block. Certainly it's between spiral or tersa (or similar system). As a commercial enterprise I have got very used to the tersa system and for the shear speed of changing blades on a 4 sider I believe it's a good system for me. The finish is on a par with yours, however even if it loses it's edge after a while it doesn't really matter as everything goes through the speed sander as well.
I suspect noise is much better with your system, tersa are incredibly quiet initially but as they dull the noise increases, it's a good indicator of a blade change.

Like you Bob I like the tersa blocks on my 4 sider but have just got a price for changing the vertical heads to spiral, as we tend to plan mostly 20mm to 40mm thick section we only use a small bit of the knife and my thinking is that at least with a spiral block in those 2 heads I can move the cutters around in the block.

There is nothing more annoying than the hidden staple in the edge of the board.

Can you not swap the heads in between knife changes so you use the top and bottom of each blade, in effect getting 4 fresh cuts from one blade. I do this on my vertical knives if all I have been running is framework or drawer box material.

Staples hide until it's to late and you see them enter the machine at the last moment.

 

[tomatwark]

Thanks Bob

That is so simple.

Although I can just swap the knives from the front to back and back to front as I don't need to take the blocks out of mine to change the knives.

Cheers

Tom