Thread: Scalloping Marks Left by all Helical Spiral Head Cutters?

Timbecon Response:

Glad to see you're having some fun on the forums.
I'd save the money and bring it in for your sake. If you were to start a case with VCAT, our solution would be that it is brought in for a warranty assessment.
Unfortunately, there is only so much we can assess from photos alone. I can assure you if it is brought in it would be thoroughly assessed for faults.

Our warranty process is pretty quick and painless. I'm sure some members of the forum could vouch for us there.

I'm suspicious the cutters or some of the cutters are not the correct size or incorrectly sharpened or drilled off centre. If not then the head itself may be the issue. Either way the thing's a dud. The only thing that can cause that type of finish is misalignment of the cutting edges. Now what is causing this could be several different things multiplied by the number of cutters I knew there was a reason why I stuck with the old straight blades. Its so much easier when you only have to count to three.

As some will have seen this issue is reported on the web. In most cases whilst it looks bad, it is not.

The Shelix unit here left marks visible under oblique light which are only .001" deep (1/1000" or 0.0254mm).

Scalloping Marks Left by a Helical Jointer Head

If yours are 0.5 mm that is quite extraordinary.

regards

Originally Posted by Wol

As some will have seen this issue is reported on the web. In most cases whilst it looks bad, it is not.

The Shelix unit here left marks visible under oblique light which are only .001" deep (1/1000" or 0.0254mm).

Scalloping Marks Left by a Helical Jointer Head

If yours are 0.5 mm that is quite extraordinary.

regards

I just realised everyone's mentioning 0.5mm, its actually 0.05mm. I was using a digital depth gauge.

Why not pass I piece of wood through and then turn the dial so that your next pass is exactly 1MM, which should be acceptable to Sherwood. You now have a controlled sample that you can take to where you bought the machine and get them to thickness the other side taking 1MM off right there in front of you and then compare the 2 sides. I think this is the least they can do, if they are in the business of selling woodworking machines then they should have a number of machines setup in their showroom to demonstrate to customers, to help them decide on whether the machine is what they are looking for.

Originally Posted by Camelot

Why not pass I piece of wood through and then turn the dial so that your next pass is exactly 1MM, which should be acceptable to Sherwood. You now have a controlled sample that you can take to where you bought the machine and get them to thickness the other side taking 1MM off right there in front of you and then compare the 2 sides. I think this is the least they can do, if they are in the business of selling woodworking machines then they should have a number of machines setup in their showroom to demonstrate to customers, to help them decide on whether the machine is what they are looking for.

I never thought of this, thanks Camelot. I will contact Timbecon now with that suggestion.

I have been running some White Silky Oak (WHO) through my Sherwood helical head thicknesser this morning. The WHO came from Crocy which we believe is Stenocarpus sinuatus, very similar to Northern Silky Oak but with much tighter grain.

The images attached were taken with a low angle light behind and to the RHS of the board. Both front and back faces are shown. The only marks on the face that are perceptible are from minor nicks in the cutters or from debris on the platten of the thicknesser. All of those marks will be taken care of with a light pass through the drum sander or very minimal sanding with the random orbital sander.

The last image does show the regular banding from the spiral cutters, however I would not class them as "scallops" because they are visually apparent, but barely perceptible to the touch.

Is this just down to the slightly different designs of helical head? Looking at the Sherwood webpage it looks as though the actual cutting edge of each insert is aligned straight with the axis of the cutterhead, and all the rows of cutter inserts appear to be lined up one behind the other?

Contrast that with the Shellix where the cutting edges of the inserts are at a very pronounced angle to the direction of cut (more of a shearing action), and the rows of cutter inserts appear to be displaced slightly between rows to give overlapping cuts? I've only ever used a Powermatic thicknesser with spiral head (not my own machine), but the finish was indistinguishable from my JET JPT310 which has 3 straight knives.

Originally Posted by Mobyturns

I have been running some White Silky Oak (WHO) through my Sherwood helical head thicknesser this morning. The WHO came from Crocy which we believe is Stenocarpus sinuatus, very similar to Northern Silky Oak but with much tighter grain.

The images attached were taken with a low angle light behind and to the RHS of the board. Both front and back faces are shown. The only marks on the face that are perceptible are from minor nicks in the cutters or from debris on the platten of the thicknesser. All of those marks will be taken care of with a light pass through the drum sander or very minimal sanding with the random orbital sander.

The last image does show the regular banding from the spiral cutters, however I would not class them as "scallops" because they are visually apparent, but barely perceptible to the touch.

This is cheeky, but I don't suppose you have any scrap walnut you can pass through?. Thanks again for the photo's, the Planer sure as hell does a good job when it works. I'll have to try some experimentation see if I can put an end to this problem of mine.

I might take some photo's if I can of the cutter head see if there's any design differences that may be causing excess scalloping...

If you want to have a play / experiment . It would be interesting to see what it looks like when a board is put through , leave the machine at that setting, then stain the just machined surface of the board with a dark stain. Just a thin black or dark brown . Stain only, no finish or shellac . Dry it off with a heat gun . Then re pass the board through on that first setting to see what happens to the stain . It should be nothing at first or it may be like whats called a spring cut on a metal lathe where the reduced pressure allows a tiny cut . First see what that looks like . The removed stain should show it up well . Take a picture . Show us . Then give a fraction of a turn so the blades take a bit more . More pictures. It may show if the blades are set out of alignment maybe ? like one side of the blade is cutting more than the other on all of them . Possibly a machining fault when the head was machined ? Possibly showing they are not seated correctly. I don't know , it may be just interesting to try out and see what you get .

Originally Posted by auscab

If you want to have a play / experiment . It would be interesting to see what it looks like when a board is put through , leave the machine at that setting, then stain the just machined surface of the board with a dark stain. Just a thin black or dark brown . Stain only, no finish or shellac . Dry it off with a heat gun . Then re pass the board through on that first setting to see what happens to the stain . It should be nothing at first or it may be like whats called a spring cut on a metal lathe where the reduced pressure allows a tiny cut . First see what that looks like . The removed stain should show it up well . Take a picture . Show us . Then give a fraction of a turn so the blades take a bit more . More pictures. It may show if the blades are set out of alignment maybe ? like one side of the blade is cutting more than the other on all of them . Possibly a machining fault when the head was machined ? Possibly showing they are not seated correctly. I don't know , it may be just interesting to try out and see what you get .

G'day Rob,

I'll give it a go and post the results. In all fairness I've run a few small American Oak boards through which were rough cut and slightly warped they came out totally flat with the jig I made so I blasted them with a quick ROS 60 & 120 grit to remove the scalloping and slight snipe, they came up lovely.

thumbnail_IMG_9075.jpg thumbnail_IMG_9076.jpg

Rob,

This youtube guy did something similar to what you mentioned I think, using a finish to see what the scalloping looks like.

Byrd Shelix Cutterhead - Scalloping issue demonstration - YouTube

One thing I am pleased to see is there is ZERO tear out with everything I've passed through it.