Dovetail Joints question

[Steliz]

I have just made my first attempt at dovetail joints on some drawer boxes for my workshop.
I had some low grade pine that I wanted to use up so I milled it down to size and started with the tails. When cutting out the waste I found that the wood was too soft for my sharp chisel to cut across the grain. The wood just crushed even with a gentle bump using my hand. The solution I used was to bandsaw the waste out and smooth to the lines with a file.
Is the reason for this down to the poor quality pine?

 

[thetyreman]

chisels have to be ultra sharp with pine, much sharper than with a hardwood, you have to be very sensitive to the wood and grain, it sounds like the chisels were nowhere near sharp enough from everything you are saying, it should compress very slightly (when hit harder) but not crush or rip out..

 

[MikeG.]

Apart from a razor sharp chisel, I also advocate using only a 1/4" chisel, and taking off no more than 0.5mm for the final couple of cuts having removed most of the waste with a coping saw. Fast grown plantation pine can be difficult for dovetails, but it is possible to do a nice job if you follow the above, and proceed with care.

 

[Steliz]

My chisels are a set of recently bought Drapers that have been given a thorough re-sharpen and I thought they were sharp. I'll sharpen again and have another go on the next drawer.
Thanks.

 

[thetyreman]

you should be getting very clean cuts if it was sharp, what is your sharpening method? are you stropping them once they go through the grits?

 

[AndyT]

Last time I was being careful about dovetails in pine, I went to the trouble of sharpening a chisel to about 25° rather than the usual 30°. This made a noticeable difference. You do need to be taking fine paring cuts, not malleting out big chunks.

 

[Orraloon]

I find pine can sometimes to be more difficult than hardwood as it has hard and soft bits to contend with. Sharp is the key so unless it can shave the hair off your arm you are not there on sharpness.
Regards
John

 

[MikeG.]

I'd contend that the "shaving your arm" test doesn't apply in this case, because the widest chisel you should be using to tackle across grain work in pine is 1/4 inch.........and anyone who tries to shave with a quarter inch chisel is a masochist. :lol:

 

[Rich C]

I was cutting some dovetails in pine last night. I had started with what I thought was a sharp chisel, it felt sharp, but when I tried to pare a sliver with it, it was clearly not sharp enough - felt a bit as you describe. I gave it another pass on the stones and really made sure I got a good edge and it made a huge difference.

FWIW I sharpen all my chisels to 25 degrees.

 

[Droogs]

.........and anyone who tries to shave with a quarter inch chisel is a masochist. :lol:

Mike apparently enough do, there is even a club you can join

https://www.google.com/url?sa=i&rct=j&q ... 2927798862

 

[That would work]

Hopefully I didn't miss this in a post but I assume you are using a marking knife or cutting gauge to mark the shoulders first? If you are then this step alone should negate the problem. Then as mentioned ultra sharp chisels with a lower than usual angle.

 

[Cheshirechappie]

There's another approach that's suitable for 'functional' pieces that don't have to have a first class finish - workshop drawers would fit that description - and that's to pare about half way through from each side, taking care to get the cuts clean on the outer surfaces, but not worrying too much about break-out on surfaces that will be hidden once the joint is assembled. You still need sharp chisels to ensure the clean cut at the outer surfaces, though.

With pine, you do have a little bit of latitude with fit, so it's best to cut the joint for a tightish fit, whack it together, and allow the wood to compress a little. You can't really do that with hardwoods - and it's not good practice for first-class work either! Once assembled, clean up the outside with a smoothing plane, and final appearance should be reasonable.

 

[AndyT]

The late Jeff Gorman's site covers the problems here, for anyone wondering

http://www.amgron.clara.net/whereyoustart27.html

Very useful site for a lot more besides.

 

[Steliz]

OK, I switched to the 6mm chisel and re-sharpened on a 1200 diamond stone at 25 deg followed by a leather strop and I also removed the secondary bevel. The result is definitely a big improvement, thanks guys. Must try harder with my sharpening!
I marked up with a propelling pencil rather than a knife although I do have one. I should have used it to break the surface fibres, I realise that now.

For my first attempt at a drawer using dovetails I got 1 corner with a snug fit, 2 that were a little loose and 1 that is embarrasing! I have 2 more to make so it's all good practice.

 

[That would work]

Yes once the surface fibres are severed you will be fine.
Using a marking knife or cutting gauge is ABSOLUTE standard practice for marking out across the grain be it dovetails, tenons etc etc.

 

[MikeG.]

OK, I switched to the 6mm chisel and re-sharpened on a 1200 diamond stone at 25 deg followed by a leather strop and I also removed the secondary bevel. The result is definitely a big improvement, thanks guys. Must try harder with my sharpening!
I marked up with a propelling pencil rather than a knife although I do have one. I should have used it to break the surface fibres, I realise that now.

For my first attempt at a drawer using dovetails I got 1 corner with a snug fit, 2 that were a little loose and 1 that is embarrasing! I have 2 more to make so it's all good practice.

Great.....that's a good step forward. Pine isn't easy to work with. Now, get into the habit of marking all your joints with a marking knife and a gauge, and leave the pencil for just roughly showing you where to start and stop with those. And practise, practise, practise, both joint making, and sharpening. It'll quickly become second nature.

 

[woodbloke66]

I have just made my first attempt at dovetail joints on some drawer boxes for my workshop.
I had some low grade pine that I wanted to use up so I milled it down to size and started with the tails. When cutting out the waste I found that the wood was too soft for my sharp chisel to cut across the grain. The wood just crushed even with a gentle bump using my hand. The solution I used was to bandsaw the waste out and smooth to the lines with a file.
Is the reason for this down to the poor quality pine?

As others have said, pine is tricky stuff to work with and even more so if it's quickly grown with wide annual ring spacing...the type of stuff that you often find in the 'sheds'. Really good quality pine is out there, mostly in builder's yards and decent timber merchants, but you've got to go hunt for it and turn a good few boards over. Look especially for lack of knots (or just small ones) and pay close attention to the end grain.

Just by chance I happened to have this piece of pine loafing around in the utility room and it's fairly exceptional in that the annual rings are around 0.5mm or so apart, meaning that it's very slow grown. This is the sort of stuff you should be looking for and it's light years away from the horrible stuff that you can buy in the 'sheds'. Cutting dovetails in this sort of pine is a complete revelation, though you'll still need really sharp chisels - Rob