Chisels vs. Pine

[Andy Kev.]

Good Morning All,

I'm currently getting into the final stages of making a 3' x 3' book case. It is made up of a number of boards of knot-free pine. The main joinery consists of through tenons for the shelves. The problems I have centre on the use of chisels. No matter how sharp they are - and they are very sharp - small indentations around at least some of the mortices seem inevitable. I put this down to the nature of the wood itself with the changes between very hard and relatively soft areas.

Also in two places where I was a bit careless with chopping through (I have been working the mortices from both sides of course) largeish flakes broke off on the far side. I'm going to get around all this by taking a router to the tenon ends and their immediate surroundings and inlaying what I hope will look like decorative plates of a contrasting wood - possibly oak, but that defeats the object a bit because I like to use hand tools as far as possible.

I only have this problem with normal pine (Zirbel pine on the other hand is wonderfully easy to work) in contrast to hard woods. The only reason for sticking with pine is that it does look quite attractive. Any thoughts?

To go slightly off topic, I'm thinking of finishing it with a few coats of walnut oil, which leaves a pleasant, neutral sort of finish.. Has anybody got any better recommendations?

 

[MattRoberts]

Are you cutting the edges of the mortise with a knife? Soft pine is terrible too work with, but by cutting your pencil lines with a knife, and then slowly working towards the knife lines with the chisel, it lessens the possibility of crushed fibres around the edges of the mortise.

Also, when chopping the mortises, favour chopping across the grain rather than with the grain when possible. If you chop with the grain you run the risk of large chunks ripping out

 

[mr edd]

Rob Cosman mentions grinding the primary bevel to 17 degrees for chisels that are only used for soft crumbly wood.
That might not be suitable for morticing work unless you only use the specially prepared chisel for very thin cleaning to the line cuts towards the end of the process.

I have not tried this.

I think the video is on his youtube channel. Hope this helps.

Regards

Edd

 

[AndyT]

I find it helps to only take a very fine cut and use a slicing cut. If you hit the chisel hard, the soft layers are not strong enough to support the hard layers. Take a sideways slice and you stand a better chance. A bit like slicing a very freshly baked loaf.
Cutting some pine dovetails recently I also tried a shallower angle on the chisel and it did help.

 

[custard]

Rob Cosman mentions grinding the primary bevel to 17 degrees for chisels that are only used for soft crumbly wood.

I've never gone that far, however I keep a couple of odd chisels ground to about 20 degrees and honed to around about 23 degrees. It does make a real difference on softer timbers like Pine or Poplar, delivering noticeably cleaner end grain cuts and avoiding almost all the crumbling that the OP mentioned.

 

[Argus]

Agree with what has been said previously.

I suppose that fast-grown pine with alternate hard/soft, summer/winter growth will present slicing issues typically where the blade leaves a hard piece of grain and enters a softer bit. The Southern Yellow Pine that is imported to the UK is a good example of this. Not my first choice for precision cuts, but….………..apart from sharp edges there are ways around this.

Here’s one that works if you need clean edges to the mortice hole: It is a bit involved, but does offer the prospect of undamaged edges by using a sacrificial scrap of wood to take all the punishment.

Before you start, prepare a couple of pieces of thin scrap wood to go over the mortice hole each side about 3 – 5 mm thick is OK. If you use PVA water-type glue, dilute it a little and glue them over each side where the hole is to be cut with a bit of paper in between. Let it dry out. Mark it all out in the normal way using knife marks for the edges on the patches, then cut down absolutely vertically to make your hole from both sides. Make sure that it fits the tenon section to your satisfaction.

When finished, a paring action at the glue junction with a flat chisel both sides will remove the patches when the cutting is done and you should have clean edges to the mortice holebelow ...... and a few traces of glue/paper to scrape off around the edges.

Any surface indentations can be steamed out with a damp rag and an electric iron.

You can exploit the softness of pine to make the tenon a tight fit in the mortice by very gently compressing the opposing faces of the tenon in a vice, before you start. Gently, don't overdo it! Then cut and fit snugly in the hole. The moisture in the glue will swell it out when assembled. Sounds heretical, but it works.

Good luck

 

[jlawford]

Knife wall to mark each end of the mortise accurately and sever fibres.
Work from the end of the mortise rather than starting in the middle taking care to protect each end by staying away from the knife wall and starting with gentle hammer taps.

I started woodworking about a year ago following Paul Sellers’ method and have no bruised mortise ends in softwood.

https://m.youtube.com/watch?v=aBodzmUGtdw

 

[custard]

I mainly use chisels with a more acute angle for dovetailing. Generally speaking bruising around mortices isn't a problem as it's obscured by the tenon shoulders. But there are exceptions.

Through tenons need to be much cleaner as they're so visible, I do quite a few wedged through tenons and in softer timber like Elm (as in this photo) I find acute angled chisels useful,

Another application is with blind tenons, where again there's no shoulders to cover up any bruising. I won't bore you with the constructional details but blind tenons are quite common in chairmaking, where you need the back bars to "float". Here are blind tenons in Swiss Pear, quite a soft timber and another example where anything other than ultra crisp mortices would be a disaster,

 

[Andy Kev.]

Thank you all very much for the replies. I'm beginning to take the view that wherever I have the option, I should avoid pine. However, when I do work with it I will slow down a lot, hit the chisel more gently and apply Andy T's advice about the fine, slicing cut.

The other side of coin is that I've just spokeshaved a long curve onto the front edge of one of the sides (it reflects the fact that the shelves decrease in width as one goes up the book case) and the wood couldn't have been more accommodating. It seems to plane and saw well but the difficult bit is chiselling.

 

[Jacob]

Thank you all very much for the replies. I'm beginning to take the view that wherever I have the option, I should avoid pine. However, when I do work with it I will slow down a lot, hit the chisel more gently and apply Andy T's advice about the fine, slicing cut.

The other side of coin is that I've just spokeshaved a long curve onto the front edge of one of the sides (it reflects the fact that the shelves decrease in width as one goes up the book case) and the wood couldn't have been more accommodating. It seems to plane and saw well but the difficult bit is chiselling.

Pine can be lovely stuff! Very under appreciated - there are lots of other softwoods too, well worth looking at.

Morticing shouldn't be a problem. Sharp chisel - 30º regularly touched up to keep the edge fresh. Modern sharpening makes this difficult - you will have to revert to the quick freehand dash up and down the stone, dipping for a rounded bevel, work like a carver and polish/hone the end of the bevel and the face.
Start in the middle - ignore the end wall of the mortice til very last and do a gentle cut to get it cleaned up without bruising.
Through morticing - always support the workpiece solidly on a bench and only work from above, half way through (and a bit more) from each side.

PS Cosman's 17º is nonsense and impossible outside a precision engineering establishment!

 

[custard]

Cosman's 17º is nonsense and impossible outside a precision engineering establishment!

Not at all. The Sorby Pro Edge that you and I both use can grind right down to 15 degrees, grinding a 17 degree primary bevel would be the work of seconds.

 

[bugbear]

The problems I have centre on the use of chisels. No matter how sharp they are - and they are very sharp - small indentations around at least some of the mortices seem inevitable. I put this down to the nature of the wood itself with the changes between very hard and relatively soft areas.

You can whack away in the middle of the mortise. But as you get near the ends (and final surfaces), you need to decrease the forces you're applying. If your chisels are already as sharp as you can make them, you simply need to take either cuts at a gentler angle, finer cuts, or both.

As a thought experiment - stop thinking about mortises. Imagine the cut sequence you would make to square off a piece of 25mm square pine using only a chisel. You wouldn't just smash the chisel across the end at 90 degrees using a mallet!

Also in two places where I was a bit careless with chopping through (I have been working the mortices from both sides of course) largeish flakes broke off on the far side.

Well - you know what you did wrong here. In the words of Joyce Grenfell - don't do that!

BugBear

 

[Phil Pascoe]

^^^ Maybe chisels for pine - or chisels with pine, even. Chisels versus pine might be your problem.

 

[Jacob]

Cosman's 17º is nonsense and impossible outside a precision engineering establishment!

Not at all. The Sorby Pro Edge that you and I both use can grind right down to 15 degrees, grinding a 17 degree primary bevel would be the work of seconds.

There must have been more mortices chopped in pine than any other material - think of all those doors and windows from 18C on, all done with 30º mortice chisels.
It isn't difficult; it's dead easy.
Our OP is a beginner - that's his only problem. Keep at it Andy Kev you will get there !! But you do need to be able to freshen an edge - a little and often.
Nobody would grind a chisel to 17º and no it wouldn't be easy - not even with a Sorby Pro edge.

 

[Jacob]

The problems I have centre on the use of chisels. No matter how sharp they are - and they are very sharp - small indentations around at least some of the mortices seem inevitable. I put this down to the nature of the wood itself with the changes between very hard and relatively soft areas.

You can whack away in the middle of the mortise. But as you get near the ends (and final surfaces), you need to decrease the forces you're applying. If your chisels are already as sharp as you can make them, you simply need to take either cuts at a gentler angle, finer cuts, or both.

As a thought experiment - stop thinking about mortises. Imagine the cut sequence you would make to square off a piece of 25mm square pine using only a chisel. You wouldn't just smash the chisel across the end at 90 degrees using a mallet!

Also in two places where I was a bit careless with chopping through (I have been working the mortices from both sides of course) largeish flakes broke off on the far side.

Well - you know what you did wrong here. In the words of Joyce Grenfell - don't do that!

BugBear

Yes to both comments! :lol:

 

[ED65]

To go slightly off topic, I'm thinking of finishing it with a few coats of walnut oil, which leaves a pleasant, neutral sort of finish.. Has anybody got any better recommendations?

What kind of protection do you feel the finished thing needs once in place? Walnut oil is a perfectly acceptable finish for items that don't need a whole lot of protection, which would usually include bookcases since they're rarely if ever used to rest a drinking vessel on for example.

On the practical side of actually doing the finishing to begin with it's better to use walnut stand oil or another modified version of the oil, or add metallic driers yourself, because basic walnut oil cures even more slowly than raw linseed oil so it could take ages and ages for a few coats to cure, but other than that it's fine in a clean environment. If you needed something better then a simple oil/varnish blend is one step up. A step or two up from this would be wiping on some thin coats of straight varnish.

Not a lot of difference in appearance between each of these options it must be said, but a wide gulf in the level of protection, both from water and other liquids and from dust.

 

[Paddy Roxburgh]

largeish flakes broke off on the far side

Superglue and activator spray are your friend here, as long as you position the flake correctly, after one pass with the plane it's pretty much invisible.
For the exit side of the through mortise I would suggest carefully cutting with a knife and removing small chips on the first pass without trying too achieve much depth, for this particular task I would use a bevel edge chisel not a mortise chisel, but that's for another thread. If I still had some bruising/chipping I would take a couple of passes with the plane after the mortise is cut.
Paddy

 

[Jacob]

largeish flakes broke off on the far side

Superglue and activator spray are your friend here, as long as you position the flake correctly, after one pass with the plane it's pretty much invisible.
For the exit side of the through mortise I would suggest carefully cutting with a knife and removing small chips on the first pass without trying too achieve much depth, for this particular task I would use a bevel edge chisel not a mortise chisel, but that's for another thread. If I still had some bruising/chipping I would take a couple of passes with the plane after the mortise is cut.
Paddy

OK for one mortice. But suppose you have to make something with four of the boglers? And four of them = 16!! :shock:
Much better to get your basic technique up to scratch.
Morticing in softwood is dead easy - you just have to work it out.

 

[thetyreman]

pine can just be arkward, I think spruce is even worse for knots, I've had some pieces of pine that are extremely hard, it varies a lot between each piece, you have to read the wood and work with it, not against it. You probably just need more practise and maybe even sharper tools, it's difficult wood to work, but you need to sharpen very regularly

 

[Jacob]

NB walnut oil is very expensive and intended for culinary use. Wasted as a wood treatment.
Just use linseed - a fraction of the price and tried and tested over hundreds of years.