Feeling crushed!

[Andy P Devon]

Relatively new to this...
Whilst chopping cross-grain (pairing out the gaps in dovetails, I keep doing what looks like crushing the fibres of the wood. By this I mean bending the ends of the 'straws' of the wood fibres (using Paul Sellers' analogue of wood being a bundle of straws).
Although most of this damaged material is hidden within the resultant joint, I'm not happy - all those YT videos out there with perfect cuts.....
This is particularly noticeable when I've used a mallet with the chisel.
I've checked my chisel is sharp - can shave my arm-hairs and slice paper cleanly.
I suspect it might be to do with the quality of the wood (it's unspecified 'white wood' from B+Q).
I have tried it with some reclaimed floorboards (oak??) and still get it, although less so.
Would anyone out there agree with this or is there a technique flaw I'm missing???? It feels like I must be doing something wrong as I never see the same thing happening in YT land.
Any help very much appreciated.

 

[Ttrees]

The waste is simply providing too much resistance.
Depending on how much you think it matters you could switch to pairing sooner.

Tom

 

[sunnybob]

This is a sharpening thread in the making.....
You chisel might well be sharp enough to slice paper, but what happens when you just PUSH the chisel into the paper?

From a completely "know nothing of sharpening other than what I've read" background, I think you have the wrong angle.
If its a blunt angle, greater than 30 degrees say, it will just crush the fibres.
My wet stone sharpening system tells me that 25 degree is optimal (stands back and waits for the fighting to start :roll: :lol: :lol: )
And of course, I doubt theres a softer wetter wood available than B&Q is selling :roll:

 

[Hattori-Hanzo]

Rob Cosman answers the problem well here.

Like sunnybob says changing the chisel angle should help.

https://www.youtube.com/watch?v=-_QnPh347WA

 

[Fitzroy]

Mike’s rule of halves will also help. Never cut away more than half the distance to the line in any chop. Until you have 0.5mm to remove at the end.

Fitz.

 

[MikeG.]

..... the quality of the wood (it's unspecified 'white wood' from B+Q)......

There's your answer, right there.

The only way you can chisel in any way neatly in this crap is to use a tiny, razor sharp chisel, taking only a sliver at a time. "Mike's Rule of Halves" applies, only more so in this grotty sticky pulp. Don't try to use any chisel wider than 6mm, even if your socket is 25mm wide or more. Do yourself a huge favour and buy some better wood........and never ever buy wood from B&Q again. Go to a builder's merchant or a timber merchant and buy redwood at the very least, but ideally you'd practise on ash or beech.

 

[Lons]

Another point to watch is that you keep the chisel exactly perpendicular as it's a common fault to lean the chisel back to push out the waste.
Doing that will crush the edge of the wood every time, try it on a bit of scrap and you'll see what I mean.

 

[MikeG.]

You can lean it slightly past the perpendicular, thus undercutting the shoulder line by a tad. No harm in that at all, and it helps stop the chisel sliding through accidentally and destroying your gauge line on the other side of the workpiece. It also removes the step of cleaning that face up and checking for square.

 

[Andy P Devon]

Rob Cosman answers the problem well here.

Like sunnybob says changing the chisel angle should help.

https://www.youtube.com/watch?v=-_QnPh347WA

Awesome video - my answer, I suspect!!!!!!!!!!!!!!!!!!!

 

[ED65]

By this I mean bending the ends of the 'straws' of the wood fibres (using Paul Sellers' analogue of wood being a bundle of straws).

The analogy of wood's structure being like straws is not Paul Sellers's, it goes way back. Before there were drinking straws it was likened to a bundle of hollow reeds. Sorry, just that too many things being misattributed to Sellers (partly due to him actually crediting things to himself that in no way have their origins with him)!

I don't know what Rob Cosman says in that video so apologies if parts of the following repeat any of it.

I've checked my chisel is sharp - can shave my arm-hairs and slice paper cleanly.

There are levels of sharpness and as someone relatively new to this there's every likelihood your edges aren't as sharp as they could be. This is not to take anything away from how good they are now, those are indicators of pretty sharp.

But a much more telling one is whether a chisel is capable of paring pine end grain. When they can leave a clean, untorn surface (almost glossy sometimes) that's a level of sharpness quite a bit above shaving and paper slicing. If your chisels can do that and you're still getting the crushing effect then you'll know it's the wood that's largely to blame, with technique being a possible component as well.

Be aware of when you're chopping and when you're paring and how the wood reacts differently. Chopping shouldn't be expected to leave a clean end-grain surface, with the more material you remove the greater the likelihood. Paring on the other hand should, except when the wood is so dreadful that it makes it impossible.

It feels like I must be doing something wrong as I never see the same thing happening in YT land.

There are videos that expressly don't try to hide the reality of this happening, since it's actually not at all uncommon. Offhand I can only remember two, but there are sure to be others. The main one I can think of is from Wortheffort, where he highlights that it happens on camera during his demonstration of chopping dovetails; I can't remember the specific video but it shouldn't be too hard to find if you want to see it. The second is a video featuring Frank Klausz (not sure on which channel, sorry) where he says how hard it is to avoid in wood with wild grain; the wood is walnut in his case, showing that this isn't only something you can expect using junk woods.

Once you get accustomed to looking out for it you will spot this occurring where no mention is made of it. This can be because it's largely not important, but sometimes it will be because the video creator is trying to hide snafus and appear more expert.

 

[AndyT]

As well as the good advice already given, have a look at what the late Jeff Gorman said on the subject

https://jeffgorman.uk/dovetailingdetail ... orchoppers

In fact, read all of his site - it's an excellent guide.

 

[Derek Cohen (Perth Oz)]

When chopping waste, I never take more than 2-3mm slices.

Here is a video I put up on YouTube a few days ago, making lipped half-blind (lapped) sockets ...

https://www.youtube.com/watch?v=X0Ic08ERaf0

This is a real-time video - no editing. So skip the parts as they bore you. Hopefully some of it will amuse. Or watch at bedtime if you are insomniac

Regards from Perth

Derek