What bevel angle for dovetail work?

[ByronBlack]

I've been practising hand dovetailing today, and have noticed that I'm having a spot of bother with the chiselling aspect. I have a set of AI bevel edge chisels, and I can't seem to get neat results using these. I'm working with hard maple, and the paring is quite tricky.

The chopping part seems to be ok.

My chisels are ground to a 25deg with a 30deg micro-bevel. For better performance, would I be better off going to 20deg single bevel?

Here's my first attempt at dovetails for a good part of 3 years (not too bad?)

I'm of course knifing a line to work from, but trying to pare it all flat and parallel is quite tricky and despite my chisels being sharp - they don't seem to be great at paring.

Any thoughts?

 

[Shane]

I've never needed to change bevel angles on my chisels, but I'm a chisel heathen and use stanley dynagrips for my dovetails with no trouble at all, I'd say if those are your first attempt in three years you're doing fine, just do a couple more for practice, just take your time

 

[ByronBlack]

Cheers Shane - I have 4 small boxes to do, so will have plenty of practice, hopefully I can re-master the chisel part.

 

[OPJ]

Hopefully, in time, you'll have the confidence to split your pencil lines in half with the saw, meaning you won't need to use a chisel to pare them. :wink:

Otherwise, not bad at all for your first attempt in three-years. Personally, I would have the central pin a bit smaller - perhaps only 3mm or 4mm wide at the narrowest point.

 

[Philly]

BB
Try going to 25 degrees instead of 30 - makes a noticable difference.
With the whole different angle thing - its a trade-off. Lower the angle, the "sharper" the edge, but at the cost of a more fragile edge. If you went to 20 degrees you certainly wouldn't want to use a hammer on them.
Congrats on the DT's, by the way. Not a bad attempt - as Shane said, another couple of practise joints and you'll be in the zone!
Cheers
Philly

 

[bugbear]

I'm of course knifing a line to work from, but trying to pare it all flat and parallel is quite tricky and despite my chisels being sharp - they don't seem to be great at paring.

Any thoughts?

Yeah - really soft (cheap!) wood is really hard to pare. Try to find/buy/obtain some harder wood e.g. sapele. You'll get on a LOT better.

BugBear

 

[MickCheese]

I'm of course knifing a line to work from, but trying to pare it all flat and parallel is quite tricky and despite my chisels being sharp - they don't seem to be great at paring.

Any thoughts?

Yeah - really soft (cheap!) wood is really hard to pare. Try to find/buy/obtain some harder wood e.g. sapele. You'll get on a LOT better.

BugBear

BB said he was using Maple :?:

Mick

 

[ByronBlack]

Thanks for the tips/info chaps.

Just for clarifcation bugbear - this is hard maple, certainly not a soft wood.

Also, when I say i'm paring - i'm not touching the side walls of the pins or tails at all - these are left straight from the saw (dozuki). It is paring the base that is where i'm getting most of the gaps.

I mark the thickness of the stock on both sides, then knife the line, I chisel just in front of that line to remove the waste, and then pair back to that line - it's that aspect I'm having trouble with in getting that base flat and parallel so that when the dovetail goes together it creates a nice tight join.

Here's a pic after the sawing (no paring):

And here's the results of chopping/sawing and then paring the base:

 

[woodbloke]

BB - the flat base of the sockets can be slightly undercut (by just a gnat's wotnot) if you pare from both sides. For hand work as Philly says, try 25deg but I'd be very wary of belting them with a maul at that angle. Mark out also with a finer line on that light maple...you could get away with a needle pointed 4H pencil - Rob

 

[Derek Cohen (Perth Oz)]

Thanks for the tips/info chaps.
... It is paring the base that is where i'm getting most of the gaps.

You could try a jig/fence to keep the chisel perpendicular.

A block of wood would do, or ...

http://www.inthewoodshop.com/ShopMadeTools/AJigforParingDovetailBaselines.html

http://www.inthewoodshop.com/ShopMadeTools/ANewJigforParingDovetailBaselines.html

Regards from Perth

Derek

 

[bugbear]

I'm of course knifing a line to work from, but trying to pare it all flat and parallel is quite tricky and despite my chisels being sharp - they don't seem to be great at paring.

Any thoughts?

Yeah - really soft (cheap!) wood is really hard to pare. Try to find/buy/obtain some harder wood e.g. sapele. You'll get on a LOT better.

BugBear

BB said he was using Maple :?:

Mick

Gack - I judged (poorly!) from the pictures, and didn't read the text closely enough. My Bad.

Hmm. A thought strikes me. What width is the chisel(s) you're using?

BugBear

 

[ByronBlack]

I'm of course knifing a line to work from, but trying to pare it all flat and parallel is quite tricky and despite my chisels being sharp - they don't seem to be great at paring.

Any thoughts?

Yeah - really soft (cheap!) wood is really hard to pare. Try to find/buy/obtain some harder wood e.g. sapele. You'll get on a LOT better.

BugBear

BB said he was using Maple :?:

Mick

Gack - I judged (poorly!) from the pictures, and didn't read the text closely enough. My Bad.

Hmm. A thought strikes me. What width is the chisel(s) you're using?

BugBear

For the central pin, I use a 6mm chisel, and the for the tails I use an 18mm

 

[bugbear]

How close to the line are you chopping? You "no paring" photo doesn't show a lot of wood left to pare.

BugBear

 

[ByronBlack]

How close to the line are you chopping? You "no paring" photo doesn't show a lot of wood left to pare.

BugBear

On that particular one, I chopped to just outside the line and pared back to it, but because I wasn't having much success, I've ended up with a surface that isn't flat, and in some area's i've gone over the line a smidgeon, creating a small gap when the joint is together.

The most issues I have is not with the tails piece, but the pins piece where the sockets are larger, you can see it in the picture, it's surface is quite rough and uneven because I'm having trouble paring in a smooth manner.

 

[Mike H]

This is usually the tricky bit, keep at it and you will be surprised how it improves after a dozen or so!

You might consider making a paring jig, or at least mount the piece in the vice with a dead straight and perpendicular edged spare piece , say 15mm wide, dead on the line and in front. Also put in a backing piece. Start at the back side, cut gradually to the line and under cut a few mm in if you want to, this will avoid nasty breakout on the next bit. Then turn it over and get going on the show side. Some people pare with a vertical block instead, but I have found horizontal to give more control.

For a first class paring jig, see the models Robert Ingham built, well explained in his book, Cutting Edge Cabinet Making, which is a good read anyway.

Good dovetailing


Mike

8)

 

[Shane]

This is usually the tricky bit, keep at it and you will be surprised how it improves after a dozen or so!

Aint that the truth!

I had nightmares at college in my apprenticeship years from doing practice after practice, they made us do them all day for a fortnight, was worth it though

 

[woodbloke]

For a first class paring jig, see the models Robert Ingham built, well explained in his book, Cutting Edge Cabinet Making, which is a good read anyway.

Good dovetailing


Mike

...and a transference jig as well, which I'm in the process of building (just need to get hold of some wide ali angle) Agree about the book, not necessarily on his designs though - Rob

 

[Derek Cohen (Perth Oz)]

I don't know why I bother, but I posted a couple of these jigs early on ... :roll:

Regards from Perth

Derek

 

[ByronBlack]

Derek, I had noticed your jig, and looked at it (both in fact) but was remiss not to say so during the thread, your contribution is most definitely appreciated.

 

[Mike H]

Sorry Derek from Perth, I missed your post!

I have found over the years that a paring jig is useful, but for the transfer there are lots of methods without a jig which work really well.

For a drawer or a box with a bottom set into a grove, I find that machining the slot first and using a squared offcut of the correct thickness in the slot to get the pieces lined up is more useful than a jig. I set this lot up in the vice and hold the whole lot gently with a holdfast, check for square and mark.

If the 2 pieces are exactly the same width from machining I also cramp 2 pieces of ply (or whatever flat is to hand) either side as it squares it up even better.

If the vice jaws were out of square, then I suppose it would not work quite so well, but they would have to be really out for it to matter much.



After all these years I still think that it is important to mark up the waste before any chopping!



This has never failed me yet.

Good dovetailing !


Mike

8)