First half blind dovetail

Re: First half blind dovetail

Eliot, the fit of the through dovetail boards looks great. We now have expectations for the half-blind fit! 

With half-blind sockets, it is important to ensure all waste has been removed, especially in the corners. Anything there will prevent a gapless fit. Check the socket in the lowermost position in the photo.

Regards from Perth

Derek

Re: First half blind dovetail

Redwood takes quite a bit of skill to cut cleanly for something like this. I think you would be surprised how much easier white pine or a hardwood would be for this work.

Re: First half blind dovetail

You point is well taken; I am actually thinking about tossing away this redwood and doing just as you suggest because I have found the redwood to crumble a lot. I did sharpen a chisel to a very acute angle specifically for chopping this redwood, but I forgot to use it. What I'll do is try using it on this redwood to see how it goes.

Re: First half blind dovetail

For anything than the first class work there's a little trick: wet the end grain a little bit and it will cut like butter. I have a little spray bottle, but a wet rag works too. Wiping chisels with an oily rag protects from corrosion and in general makes chopping/paring easier. Works for planing as well, esp. around knots.

Water or mineral spirits, alcohol, etc work, but wet just a little bit. Wood swells and it could pull straight lines into curves after moisture evaporates. I don't like doing this on parts that show, e.g. mortise walls, because sometimes it looks different from a joint cut dry and it pops. But for something like a drawer's half-blind dovetail this works. 

Doesn't absolve from sharpening though. 

Re: First half blind dovetail

Kiln-dried redwood is one of the nastiest woods to work with hand tools. The variation of glass hard late wood and squishy early wood just drives me crazy every time.

However, counterintuitively low bevel angles won't work, the edge will get destroyed by that late wood. What could work is a regular 30˚angle, but sharpened very, very keenly - the very tip is polished to the highest degree you can, use a jeweler's loupe to ensure that. Or your regular main angle and a 30˚ ball park micro-bevel, whatever, the point is you actually need a strong edge rather than low angle. The late wood is at least as hard as maple, and a chisel stops cutting not because the angle isn't appropriate, but because it's destroyed as it would be in maple at this angle. A regular keen chisel somewhat surprisingly produces very agreeable surface with just a bit of early wood torn, quite acceptable. 

Another point is you have only one "difficult" surface - the socket bottoms, rest is cut along the grain. So actually clean job is required maybe within 1/8" that line and marking is critical, since redwood chips/splinters easily and deep. A marking gauge skids over the late wood, marking knife works better, but it has to be fine and go deep. I use a pencil-size utility knife, mine is yellow "Olfa", but anything that size with a fresh blade works. Go many, many light passes making sure to score late wood grain deep and clear, idk 1/32"-1/16" deep maybe. This is where a line usually goes out of true, so take your time. And the rest is up to you: either carefully chisel just that area and use this knife wall as a guide for a final cleanup. Or leave 1/16" allowance and on cleanup use the knife line as a starter. Having a fresh chisel like above just for that helps too. Everything else can be cut along the grain and 6 clean lines will conceal anything that happens in the joint. 

I've messed with redwood, hard pines, hemlocks, etc. a lot and I think finally figured how and to which extent I can work it for reasonable results. But with all the fuss and risks involved I usually just get poplar.  

Re: First half blind dovetail

Hi Eliot,

These drawers are going to look real good when finished.  Just a couple of thoughts on the redwood:

1.  Make a ledge.  JD’s recommendation to use a cutting gauge to get below the surface of the wood will help you a lot.  A little experiment you might try with your chisel:  shallow little V-cut back towards the score line to create a little ledge and further weaken the fibers.

2.  Narrow chisel.  Suggest use 1/4” rather than 3/8 or 1/2.

3.  Crushed wood.  That doesn’t crumble can be brought back level after you’re all done by simply laying a damp rag along the scribe line.  Doesn’t take long—maybe 15 minutes.

Hang in there!  This is what learning is!

Wiley

Re: First half blind dovetail

I made my first hand-cut dovetails in hard maple.  Bad move.  I made several after that in alder.  Much more forgiving, and a nice reddish tone.  Also, not too expensive.

Re: First half blind dovetail

Good work Elliot!

Re: First half blind dovetail

Looks like you've moved the baseline a bit and I suspect the same thing has happened at the lap line.  Last cut on the base and lap lines needs to have very little wood in front of the chisel.  One stroke needs to clean it up.  If you spend a lot of time futzing in these crucial areas, you're going to spoil your incised lines a healthy percentage of the time and leave a gap.  And as Warren said, you've picked a bit of a tough customer in redwood.  You actually need something harder and denser IMO.  Do not dig a trench when you incise your lines and the knife wall needs to be vertical.  The incised lap line needs to be particularly shallow or you'll end up with a gap across the tails by about half of the too-deeply incised line.  I actually prefer no more than a scratch there and register the chisel right in front of it to avoid the gap.  I was frustrated early on by a regular, hairline gap at my lap lines (end of tails) until I realized what was happening.  You can even reset your cutting gauge very, very slightly less than the setting you used on the pin board base line and then go ahead a strike a distinct lap line.  Play around with it, see what works best for you.  Hopefully these tips will save you some frustration if you're having problems.

Or …

Charlie makes a valid point. If you stray over the baseline, you will create a gap. 

My preference is to create a wall at the baseline. This prevents the chisel wandering back over it ..

Here is another view, this time a pin board. The baseline is undercut and the sockets have had most of the waste removed with a fretsaw …

Now you can pare to the baseline in safety …

Regards from Perth

Derek