Chisel tearout

[stoatyboy]

Hi - bit of a numpty newbie question would appreciate advice from those with the 'knowledge' (that's you lot!!)

Hand dovetails, saw the angles, fretsaw out the waste (leave about 1-2mm above the line), chisel out the rest of the waste (this is the bit where the pins will go so the bit between the tails) and instead of a nice flat base it seems that the chisel sort of levers out a lump of wood thats broken off below the line.

hard to describe but it's almost like it's pulling out a tooth with the roots. the outside edges are fine but inside the joint is a cavity.

chisel as sharp as I can get it. wood is 10mm thick pine.

is it the wood. me or the sharpening - or all of these?

all advice, as ever, highly welcome

Pete

 

[Henning]

Just a newbie here as well, but i've found a lower angle sometimes cut better in softwoods like pine.
It's also very prone to tearout almost no matter what you do, so the best advice for dovetails would actually be to use one of the "cheap" hardwoods. (At least that's what i've picked up here )

 

[stoatyboy]

Thanks Henning - didn't want to use hardwood for my first chest of drawers as assumed it would be more expensive and difficult to work.

shows how much I know!!

I think i'll persevere as it doesn't show on the outside - but it just bugged me - I bet it doesn't happen to Rob Cosman!

Pete

 

[woodbloke]

chisel as sharp as I can get it. wood is 10mm thick pine.

is it the wood. me or the sharpening - or all of these?


Pete

Strangely, pine is quite hard to work with for accurate chiseling as it has alternate very hard and soft growth rings. You generally need a super sharp blade honed at a lowish angle, around 25deg. My guess is that you may think your edge is sharp but it's probably not sharp enough :wink: - Rob

 

[StyXSIS]

Hi stoatyboy, could i ask how are you taking the waste out ? Is it by hand or mallett? Also you might want to put a flat piece of wood under the work and then clamp anther piece on top to match the line your cutting to guide the chisel down, also try to take as thin a slice of wood as possible just take your time with it and it will work.

 

[Henning]

Thanks Henning - didn't want to use hardwood for my first chest of drawers as assumed it would be more expensive and difficult to work.

shows how much I know!!

I think i'll persevere as it doesn't show on the outside - but it just bugged me - I bet it doesn't happen to Rob Cosman!

Pete

I'm sure Rob will have a gadget for it, which he will probably sell you for the right price.

I have 2 old chisels honed with 20 degree bevel for pine and other soft wood. I only use them with hand pressure though, not with a mallet.
25 degrees seem to work nicely on soft wood with a mallet, although requires frequent sharpening (or rather honing, i love my Tormek T-7)
to be as sharp as they need to be.

 

[Chems]

Master pine and everything else is easy!

 

[Phil Sewell]

I agree with Woodbloke. Your chisel probably isn't sharp enough. It's not slicing through the fibres. You need to be able to shave a bit of hair from your arm with it (obviously very carefully).

You will probably get some tear out from the middle of the board working from both sides even with a sharp chisel but it is hidden when the joint is glued up.

I make boxes which are all jointed with hand-cut dovetails so it's a joint I've spent some time practising!

If you can afford it I really recommend tite mark marking gauges for marking out.

Good luck!

 

[Sgian Dubh]

...the chisel sort of levers out a lump of wood thats broken off below the line.
Pete

It's most likely a combination of a chisel that could do with being sharper, and trying to take too much at once. Try this. If the space is, let's say, 10 mm at the base line, try using a 3 mm or 4 mm chisel and work down one side until you get near the base line, then work across to the other side with a 6 mm or 8 mm chisel. Finally use a 10 mm chisel to take off a final skim or two. Slainte.

 

[jimi43]

Also if you work down one side do it at an angle

Then down the other side leaving a triangle in the middle which should easily par down.

I would use a Japanese paring chisel but then I am biased. :wink:

Jim

 

[stoatyboy]

Cheers guys - loads of good stuff there thanks

I'll spend some more time sharpening and take it a bit slower on the chiseling - hopefully we'll see an improvement!

Pete

 

[Jeff Gorman]

Stoatyboy might find an illustrated answer to a familiar problem at: http://tinyurl.com/242ux82

Jeff
www.amgron.clara.net

 

[head clansman]

hi

it's a combination of things , chisel ain't sharp enough , don't use a mallet or hammer the timber is to soft to be hit with them because the chisel could be sharper it's being forced through the grain, do it by hand a whisper at a time , do it as Jim described, slowly ease back to the line a little at a time. hc

 

[TheTiddles]

As you're using pine try this...

Cut to the line, if you can mark out accurately then with a wood that yields a little you should just be able to cut and press together. With some practice it'll work on hardwoods too, the bottom of the socket is obviously the hard bit as you're not using a straight accurate saw on it.

Aidan

 

[stoatyboy]

I love you all

I resharpened my chisel, stopped malleting, took a bit off the sides first and ended up with a base to my cut as smooth as a babies bottom!

Took longer mind you but then you can't rush quality.

The best thing of all is that I know I will never make that mistake again because I learnt by doing it wrong and then doing it right - with your help - and that usually sticks

I really appreciate it thanks

Pete

 

[jimi43]

Glad to hear that you finally sorted it...great when that happens isn't it!?

Jim