Thread: darkside: cleaning handcut finger joints for better fit

Interesting post Thumbsucker. I would be interested to see if any of our darkside brothers have ever done hand cut finger joins? Its something ive always asumed was a saw/router join. Hmmm

Originally Posted by Lignum

Interesting post Thumbsucker. I would be interested to see if any of our darkside brothers have ever done hand cut finger joins? Its something ive always asumed was a saw/router join. Hmmm

I had always assoumded that finger joints would be the first port of call, when learning to cut joints by hand, being simpler then dovetails? Or so I assume.

cutting joints in mdf (or any man made product) with chisels is damm near impossible, it doesnt improve you skills or your temper

joints in man made materails are best cut with power tools

try again with some wood, your work will be more rewarding

A chisel would have to be the best choice (by hand).
It would need to be razor sharp and used by paring by hand - no hammer.

yes it can be done, but it is rather difficult for a novice woodworker

razor sharp chisel? yes we mean it

if you can shave with it (remove hair from your arm without shaving foam)

then, two hands and body weight ONLY, it will do the job you want in MDF

I've learnt recently never to pare with a chisel by hitting it with a hammer - just get the chisel really sharp and use it by hand as suggested. And by george it works, in wood anyway - I've never tried to chisel (or anything else for that matter) MDF. I'm just in the process of hand cutting my first dovetails and finishing these with a chisel. Great fun, quite difficult, but I'm sure I will improve with practice.

Although I have never tried it, I would imagine the process to be not that much different from cutting dovetails. Scribe a base line, layout the pins, cut the shoulders with a tenon saw and remove the waste with a chisel. Use a mallet with the chisel first to remove the waste almost to the line, then use a paring action to trim to the line. Undercut slightly so that the joint fits together snugly. Transfer the outline of the pins to the adjoining board so that any inaccuracies in the saw cuts are catered for.

I would do three things:
1. Skip finger joints and practice with dovetails.
2. Make sure the chisel is sharp.
3. Get some pine or something to practice with. MDF is rubbish.

One of the first boxes I ever made was exactly the same: entirely hand-cut finger joints in MDF, and I had exactly the same issues as you. The result was a wonderful learning experience, and the box still provides excellent service:



If I was going to do a hand-cut finger jointed box again, I would advise:

* Make sure the stock is cut square, is flat, and even thicknesses, and accurate to length.
* Do accurate marking out with a marking knife, wheel scribing gauge and square.
* Don't be afraid of marking your fingers slightly wider than your chisel, say 14 mm wide fingers for a 10 mm chisel. If the fingers are the same width as the chisel, the chisel will tend to bind in the fingers, and you'll tend to mush up the neighbouring fingers as you cut. Chisel accurately to depth by laying the chisel for the final paring cut directly in the line made by the wheel cutting gauge.
* Try to get the saw cuts happening so you don't need to trim with a chisel, because the more trimming you do, the easier it is to make a mess of things.
* Any chisel trimming you do, leave the outside part of the fingers alone and untouched from the saw. The assembled box will look better if you get gapless fingers meeting on the outside faces. Instead, focus your trimming efforts to the interiors of the fingers. For example, you can use the chisel to cut small chamfers on the inside edges of the fingers, to help them slide into their respective holes.
* Keep your chisel extremely sharp.
* Use chalk applied to fingers to help identify where you need to trim.
* Use a slightly curved gouge instead of a chisel to *slightly* undercut the mating faces of the fingers: leaving the borders of each finger's 'cheek' alone.
* Use a marking knife, skew chisel, or normal chisel to make sure you remove all waste from the very inside corners of the finger holes.
* Avoid files, rasps, or sandpaper for trimming the fingers: you'll end up rounding them over.
* Go slow and steady, think about what's happening, don't be rushed, enjoy the zen of wood!

Finally I agree with silentC: hand-cut dovetails are no harder or easier than finger joints. Perhaps make it out of a piece of nice straight grained tassie oak, mahogany, WRC would be better than MDF because it might be easier to cut without it splitting, and the final product is a lot more rewarding. Don't use pine, which is really hard to pare endgrain with a chisel.

Hope all this makes sense.

Don't use pine, which is really hard to pare endgrain with a chisel.

Not if your chisel is sharp