cutting mitres for picture framing

[skeetstar]

Folks, a question, how can I get dead on 45deg cuts for making picture frames?

I have a Makita 8in SCMS, and using that I can cut the faces of the joint square, but I cant get the angles to 45deg. When I measure the blade to fence angle it looks to be 45deg, but the joint made with two such cuts is not 90deg.

I am not good enough to cut them by hand.

I made a jig to sit on the bed of the Makita, but that doesn't deliver the accuracy I want.

My next plan would be to make a 45deg shooting board, but experience with the jig I made suggests that wont be any better.

I've seen folks recommend an iterative process with shims against the saw fence cut, measure, adjust and repeat until correct. that may be the way I have to go, but just wondering if anyone had any better tips.

 

[nev]

If you can cut an accurate 90deg on your saw could you use a e.g. a combination square minus the rule clamped to the rear fence to give you an accurate 45deg?
e.g https://www.amazon.co.uk/Bahco-CS300-30 ... J1X43J9XM2

 

[marcros]

shooting board. cut them on your saw as accurately as you can and finish on the shooting board.

picture frames need to be very accurate or they look dreadful.

 

[Ttrees]

Presuming your wood is surfaced with your own machine or hand plane so it registers off your fence,
Have you got a rebate plane ? you can fine tune a shooting board with one if its off a bit.
It might prove useful if you make one to get your machine or jig for it true.
Tom

 

[Beau]

shooting board. cut them on your saw as accurately as you can and finish on the shooting board.

picture frames need to be very accurate or they look dreadful.

This

 

[custard]

I've seen folks recommend an iterative process with shims against the saw fence cut, measure, adjust and repeat until correct. that may be the way I have to go, but just wondering if anyone had any better tips.

Shimming (or fine tuning your SCMS) is the way to go, it shouldn't take more than three or four attempts to get the accuracy you want and once it's done then you've got a much more useful machine.

Bear in mind though that for decent quality framing getting a clean, 45 degree cut is only half the battle. The other requirement is that each frame side must be exactly the same length as its opposite number, cutting to a line, even a knifed line, is unlikely to be accurate enough. You need a matching 45 degree profiled stop (otherwise the knife edge of the previously mitred end will get dubbed over), and you need a method of ensuring no sawdust can get trapped between the stop and the workpiece.

Good luck!

 

[ED65]

Another workaround for this problem that you might be able to use (depends on frame style) is the face up/face down thing, where each subsequent piece is sawn with the opposite face downwards. It's just like the jointing trick where the first board is jointed with the face side against the fence and then the next is done with the face side outwards. Regardless of the angles you do get they're complementary, so they cancel each other out.

My next plan would be to make a 45deg shooting board, but experience with the jig I made suggests that wont be any better.

Different kettle of fish. If a mitre shooting board is dead-nuts accurate then your mitres will be too after shooting, as long as the workpiece is held firmly against the fence of course.

 

[deema]

The normal way of making picture frames is to cut them with a shear mitre guillotine. They produce accurate cuts that the cut edges have a glass like appearance. Morso machines I believe are consisted to be the Wadkin equivalents.

 

[Alexam]

https://www.manomano.co.uk/mitre-saw/pr ... mm-2674798

 

[Brentingby]

The best thing I've ever used for mitres for picture frames is this. Perfect off the machine. No need to clean up on a shooting board and no break out.

 

[sunnybob]

not cheap, but if you make a lot of 45 degree mitres....
http://www.axminster.co.uk/axcaliber-mt ... mer-951813

 

[Racers]

Get someone else to make them, I hate picture frames.

A framer will have all the expensive kit to do the job properly.

Pete

 

[ColeyS1]

Get someone else to make them, I hate picture frames.

A framer will have all the expensive kit to do the job properly.

Pete

That's not always the case Pete ! I had several made and at the time of ordering mentioned I was a joiner and didn't really have the time to do them. They were bubble wrapped and only got to see them when I got back and unwrapped them. Nearly every joint had filler in them- I took them back a few days later !
That shop was in the Torquay area, never again !
Coley

Sent from my SM-G900F using Tapatalk

 

[transatlantic]

I find mitres to be really hard! .. so many things to go wrong. One thing to point out is to make sure you're consistent with your reference face. Don't flip flop between using the table as a reference for one cut and then to using the fence for another etc etc, which is easier said than done if the material is not flat. And as custard pointed out, the angle is only half the problem, getting oposing sections the same length is the other.

Anyway - here is another idea that will give you perfect 90 degree cuts (Don't forget thought that each cut needs to be marked and the pieces put back togeather in the same order)

 

[dickm]

No-one has mentioned the Nobex mitre saw or its imitators. I've got the "Professional" version, which cost me a princely £3 at a local car boot and it produces spot-on mitres. If you've got all the bits, which include an end stop, it potentially solves the matching lengths problem too.

But a query (sorry to slightly hijack this thread). How does it lock in positions other than multiples of 22.5degrees??

 

[Marineboy]

My Nobex has a lever underneath at the back that locks it at any angle.

 

[devonwoody]

My experience of mitre cuts is not so much the 45% marking that goes wrong but because both pieces are not really the same length and then messing about trying to equal lengths causes more trouble.

So the stop bracket is very important and pieces must be clamped when cutting, the machine shoves things around.

 

[skeetstar]

Folks all, sage replies as usual and thanks to those who contributed.

I cant justify the purchase of a Morso or similar, no space and little funds.
I'll try shims per custards suggestion, and then make a shooting board if I cant make that work on my saw.

Again, thanks all.

 

[monkeybiter]

I think one major problem often encountered with many a SCMS is that the cast fence is not straight across it's width, leading to inconsistency. A long enough piece of wood will rest across the ends of the fence, possible square to the blade, but if you're cutting the end off a shorter piece [e.g. cutting a mitred end] the timber rests on the face of the fence [as it should] but that this may be pointing back toward the rear of the machine slightly, throwing out the angle of the cut by a small but significant amount.

 

[transatlantic]

I think one major problem often encountered with many a SCMS is that the cast fence is not straight across it's width, leading to inconsistency. A long enough piece of wood will rest across the ends of the fence, possible square to the blade, but if you're cutting the end off a shorter piece [e.g. cutting a mitred end] the timber rests on the face of the fence [as it should] but that this may be pointing back toward the rear of the machine slightly, throwing out the angle of the cut by a small but significant amount.

Just another reason for a sacrificial fence!

I think the biggest problem with SCMS is the slop on the sliding mechanism. I know mine has some .. for smaller cutters, I tend to disable the slide