Mitres are harder than dovetails!

[Doug B]

You can see how these saws (even the Kapex...? :shock won't cut them spot-on every time.

Think Mr Festool might disagree with you there, Olly :lol:

 

[Noel]

I get pretty decent results with one of these:

 

[woodbloke]

swanky. I'm jealous!

This one's in 'noir' :roll:
The problem with mitres for a box or frame is not just cutting them at 45deg which is easy enough even with a Kapex, but cutting all four bits identical (or two pairs identical) This is where the shute has (I think) to score 'cos you can take just one shaving off (thou or two maybe) a mitre where needed to bring it into line with the other bits of wood - Rob

 

[Digit]

Mitres cut across the width I do with a sled on the TS, the sled has stops to ensure equal lengths.
Mitres cut across the width I do with a 45 degree router on a special home made machine.
By hand, mitres are murder!!

Roy.

 

[frugal]

I can not get mitres to fit correctly when doing them on a shooting board with a handplane, they always come out just out enough to leave one open crack when I put it all together. I have managed to ge the disc sander set up to do mitres as the table drops down to 45 degrees and is accurate.

Like anything else woodwork related what you get out is only as good as what you put in. I was pulling my hair out trying to work out why I could not get the mitres to fit on a small box. No matter what I tried the mitre ended up curved rather than straight. Turns out that since thicknessing the wood it had cupped slightly, not enough to be obvious, but enough to throw off the mitres (at which point the pieces were of course too small to put back through the thicknesser :? ).

Now before even trying to mitre anything I make sure that all of the pieces are the same width, they they are not bowed, cupped or twisted at all (no more thinking that it will all come out right in the end if I use enough clamps) and I get the digital calipers out to ensure that it is the same thickness all over and that every piece is exactly the same thickness ( I measure this down to 0.1mm as I am making small jewellery boxes).

 

[woodbloke]

I can not get mitres to fit correctly when doing them on a shooting board with a handplane, they always come out just out enough to leave one open crack when I put it all together. I have managed to ge the disc sander set up to do mitres as the table drops down to 45 degrees and is accurate.

Like anything else woodwork related what you get out is only as good as what you put in. I was pulling my hair out trying to work out why I could not get the mitres to fit on a small box. No matter what I tried the mitre ended up curved rather than straight. Turns out that since thicknessing the wood it had cupped slightly, not enough to be obvious, but enough to throw off the mitres (at which point the pieces were of course too small to put back through the thicknesser :? ).

Now before even trying to mitre anything I make sure that all of the pieces are the same width, they they are not bowed, cupped or twisted at all (no more thinking that it will all come out right in the end if I use enough clamps) and I get the digital calipers out to ensure that it is the same thickness all over and that every piece is exactly the same thickness ( I measure this down to 0.1mm as I am making small jewellery boxes).

Agreed, all bits need to prepared accurately to give yourself a fighting chance of bringing them together. Pieces also need to be dead parallel as it's opposing edges of each piece that are placed against the fence to shute the mitre...if they're even a tad out, the joint won't go together. Not too bad in a small pic frame, but in a box (say) with a 100mm long mitre, the discrepancy will show :evil: - Rob

 

[miles_hot]

swanky. I'm jealous!

This one's in 'noir' :roll:
The problem with mitres for a box or frame is not just cutting them at 45deg which is easy enough even with a Kapex, but cutting all four bits identical (or two pairs identical) This is where the shute has (I think) to score 'cos you can take just one shaving off (thou or two maybe) a mitre where needed to bring it into line with the other bits of wood - Rob

What's a shute?

Thanks

Miles

 

[wizer]

oh god don't start that again.... :evil:

 

[Alf]

Or to answer the question, a variation on the spelling of appliance more commonly referred to as a Shooting Board.

 

[Benchwayze]

If you want to be sure that all sides of a mitred insert are the correct length, there's a trick I use, when grain matching doesn't matter too much.

Cut two pieces of stock that are a little over twice the width you need and long enough or sides and ends.

Once you know you can produce a true 90 degree corner, (however you plan to cut the mitre) you then need only cut mitres on two pieces.

The simply rip them down the middle, and you have two sides and two ends that match their respective 'partners'. You also know the mitres will fit.

The length and the angles are taken care of automatically, as long as the ends are square before you mitre them.

John

 

[PerranOak]

So, basically, they can't be done without machines!

What then, is the simplest/easiest/quickest way to make a small box like the one I mitred?

 

[Digit]

Are you wanting to produce a one off or are you in to box making?

Roy.

 

[Alf]

So, basically, they can't be done without machines!

*looks at thread* Um, nope. As Rob says in one of his posts, even if you cut it with a machine in the first place, using a shooting board is an excellent way to get the most accurate fit. I concur, but there didn't seem much point in repeating it. :wink:

 

[wizer]

Indeed, as I've found, the machine is pretty pointless unless you're cutting a lot or very chunky stock.

 

[PerranOak]

*looks at thread* Um, nope. As Rob says in one of his posts, even if you cut it with a machine in the first place, using a shooting board is an excellent way to get the most accurate fit. I concur, but there didn't seem much point in repeating it. :wink:

... but for those of us with less skill ...?

Thing is, I just want a method for the odd one-off to be quick. If I'm making a "proper" piece I'll dovetail. I don't really want to setup any machine - I want to be quick - I just thought there might be a quick way of achieving the accuracy needed. Donkey's ear?

 

[Digit]

One offs then a DE is the best bet IMO PO, otherwise years of practise or jigs!

Roy.

 

[wizer]

Honestly, been there done that. I've got about as much woodworking 'skill' as Mr Bean. The shooting board requires little skill. Once it's built, all the skill you need is to push the plane forward whilst keeping it against the fence. There is a knack, but ut comes. Trust me. I've been all through this. Tried all the methods, gadgets, etc. Shooting boards are about as good as it gets if you want perfect mitres. Give it a go.

Maybe a local can show you how simple a shooting board can be.

 

[PerranOak]

Cheers wizer but it's the 45deg I can't get fof the shooting board in the first place. It's a Catch 22. I need a 45deg "thing" to make the 45deg thing that I need to make 45deg things!

Digit: DE is donkey's ear, right?

 

[Benchwayze]

Hoi Perran,

Have you an Engineer';s square, the metal type with a sliding 45 degree and 90 degree fence?

John

 

[mr grimsdale]

My approach is firstly to mark everything as accurately as pos with a 2h pencil
Then to cut and plane to the lines.
On a shooting board I'd pay attention to the lines and not expect the board to be 100% accurate. Blades may be cambered slightly out out of tilt. You may need paper shims to bring the lines in line etc.
Having done that I'd 'fit' the pieces. This is where you have to think! No use making each joint perfect as any one of them can still be pulled out when you put 4 pieces together.
So you have to look at all four together - put them together and work out where and how each joint needs trimming, with your finest block plane, bearing in mind that each adjustment affects the seating of the other end of the piece too.
You might risk gluing and clamping to close joints but then the box might be pulled into a twist. But you might be able to plane up the sides to get it square again, leaving the twist on the inside.
And so it goes on. It's down to hand and eye skills and repetition in the long run.