How do you get flush mitres?

[Fellows Framing]

Hello,

I work mainly with grained woods so not used to flat colour moulding eg flat white as in photo.

I am struggling to get flush mitre corners. I have put new blades on morso & carefully pinned them but still cant get flush corners.

Any advice or tips please? Would be much appreciated as always.

TIA
Sarah

[NTG999]

When you say flush do you mean tight mitres?
If so a few things, you mentioned new blades, are these brand new never been used Morso blades or another set you have?
If brand new I would suggest that with a (big as possible) straight edge set up the right hand fence to be perfectly in line with the measuring scale, then find the widest flat moulding you have and cut four equal sides perhaps 400mm each, then assemble in a pony clamp or strap clamp, at that point you will see the gaps, then adjust the the left hand fence; back towards you if the gap is on the inside, away if on the outside. I always put a piece of tape tight against the fence when moving towards me before I undo the locking arm in case it moves, if moving away I put tape about 1/2mm away from the fence then move to the tape. Recut all 4 mitres and test again, be aware when cutting the left hand mitre the moulding can move very slightly - this is worse on hard woods, doesn't happen on the right hand side because the measuring guide holds it

[JKX]

If when you put two lengths on your underpinner, whether it has rebate clamps, or if you have to push them together yourself, does it look OK? If so but it looks like that after pinning, your underpinner hammer may be chipped, so it’s not making full contact with the V nail
It looks like there’s a slight gap on the inside too, so do the left fence tweak as well.

[vintage frames]

Generally speaking, if there is a a gap showing anywhere across the closed mitre, then that is a fault in cutting the moulding.
As advised, check the Morso fences and make sure to hold the moulding firmly down when cutting.

There is one variable that can interfere with getting a truly flush mitre joint.
And that is the underside of the moulding itself.
It only takes a little bleed of paint finish or grit on the moulding base to wreck any chance of a flush finish.

If the moulding has a thick painted finish, try rubbing the base with some medium sandpaper before cutting and joining.

[Fellows Framing]

Thanks all for your advice.

To clarify what I mean by a flush mitre it is that when you run your finger over the joined mitre corner its smooth.

With the frames I am having issues with its uneven, one side of the corner is sligthly raised, in fact on one of the corners the inside left piece was raised and the outside right piece was raised....what is going on!!

Its not so much a gap that is the problem its the uneveness on the sight face. The photo I used it may look like a gap but its a shadow/ridge.

JKX "when you put two lengths on your underpinner, whether it has rebate clamps, or if you have to push them together yourself, does it look OK? If so but it looks like that after pinning, your underpinner hammer may be chipped, so it’s not making full contact with the V nail"
YES it looks good before pinning so may be a hammer issue - I have a old 3 minigraff pneumatic underpinner. Now you mention it may be a problem with that as it has been occasional failing to fire v nails recently or not gong right in, plus been making a clunking noise when its does fire ok. Is it a part easy to change myself? Or does it need a repair bod?

Thanks again...

[JKX]

I don’t know that machine, but on the underpinners I had changing the hammer - or the “blade” on the cassesse, was routine and simple, once I knew how of course. I always had at least one spare.

It’s something that’s good to learn as part of routine maintenance.

Maybe someone here has one who can explain and/or show how it’s done; maybe there’s a YouTube vid or online manual.

[pramsay13]

Sometimes there can be a slight difference in moulding height from one end of the length to the other, which can cause this issue. If this happens I normally put a slip of card underneath when joining so the top is flush and the bottom is out slightly.
Another possibility is a length is warped which can then cause it not to sit right. There isn't a cure for a warped piece, you just have to find it and replace it.

[theframer]

I think its a twisted piece of moulding have you got any left over to try again or replace the 2 pieces with the problem?

[Fellows Framing]

Thanks everyone. Plenty of useful advce

Plan is to get underpinner looked at and go from there with a non twisted lenght & morso adjusted...it can only be better, or even better flush!

[Justintime]

In my experience these spray finished mouldings are notoriously difficult to get looking perfect. Even when everything is setup perfectly it only takes the tiniest bit of warp/twist to give you that result. A clamp after pinning might help.
Alternatively if you're familiar with bare woods then a better closed corner finish can be achieved by sanding a bare wood, then undercoat then two coats of a farrow and ball grey with a "One Stroke" brush finished with a coat of poly vine dead flat matt. Not the advice you were asking for, but worth considering?

[Fellows Framing]

Thank you Justin.

I try not to use these flat mouldings and don't even have chevron samples but customer wanted....another instance of should of said no.

Good tip to get over issue though if arises again, thank you.

[NTG999]

You mentioned using a Minigraff underpinner, I'm not sure if the clamping is the same as my Alfamacchine but originally I used to almost exclusively use the middle clear pad, only using black harder pad for hardwoods, recently I use the black a lot more because for me it's better for the situation you describe. You want to use the hardest possible pad that doesn't mark the surface of the moulding.
When you think about it it's a battle between the wedge pushing up and the clamp pressing down, you want the flat flush top to win, as an experiment I would remove any rubber block and try on some offcuts just using a piece of MDF to protect the top

[prospero]

FWIW.....

I do a lot of bare wood frames and a few of these use wide, flat profiles. There is always a corner that is not quite
flush. Fortunately I can sand them flat before the finish is applied but even with a tiny 'step' it can be very tricky to get it perfect.
I hate those flat, glossy mouldings. Every minor flaw tends to get magnified.
If they do come out with perfect corners then it's more good luck than judgement.

[Gillthepainter]

it's rather encouraging that framers have problems with off joins, like what I do.
I find I get an off mitre when I first chop the full length. I do have a support for the end of the wood, but still feel I can get a fraction out if I'm careless.
Sometimes, if I know it's one of those days, I chop my wood 1mm too long. And take a shaving off afterwards to be sure my mitre is true.
Or as true as I'll ever get it.

I've recently had my 2 sets of blades hollow ground, so I should have better accuracy.

Plus, I avoid any and all slope frames. As I v-nail upside down, there's no way I can hold them together.

[Justintime]

You v nail upside down? I think it's safe to say you will have some of us curious. Can you elaborate or post pics?

[JKX]

Does it mean the frame is joined going away from you instead of towards you?

That’s how I did it, so my workbench with underpinner in one corner, became a huge frame support - and I never ended up standing inside a frame!

So it would mean, with a manual underpinner, you’d be pulling the corners together rather than pushing them together.

[Gillthepainter]

I'm not sure which I prefer to do, paint a painting, or make a frame for it. I thoroughly enjoy making the casements for pictures.

I was taught by a framer next door to my old studio, so I'm very fortunate to see and understand the professional process of framing. He taught me how to cut glass too, which comes in handy.
So I know what I need to "mimic" at home in the framing department. I have a 1960's Morso, which changed everything. £200 on Ebay, fully working with 2 sets of blades. Nice clean accurate cuts, within my limited abilities.

I did have a foot pedal underpinner, but in my garage there was just no room to accommodate the area I needed. Unlike the Morso which is long and thin, the underpinner needed space.
I gave it to a chap who makes his wife's frames (an engineer). I told him not to dabble with it, it's perfectly calibrated.
He proceeded to unscrew it, take it all apart to see how it worked, and now has a device that only delivers one V-nail at a time, and not very well at that. I wish I'd given it to someone else.

But I've always favoured my Benchmaster, pushmaster when it comes to V-nailing, it came all the way from Australia. It's not ideal, and you framers would be super frustrated with it. But when I clamp the freshly glued corners together, and slide the mitred join in, I get a great frame.
I can do it without, or with the push press structure. It will also deal with hard wood.

The biggest difficulty I have is holding those glued joins together. I've thought about all sorts of clamping systems, but the German spring clamps are the best for me.
It means I have to buy unpainted untreated mouldings, as I have to fill those pin holes invisibly afterwards.

If anyone here knows of a different clamping system to spring clamps, I'd like to know. I've tried belts, but when I turn my frame over, it often has had movement, and step in the mitre.
I can't think of another way to clamp those corners.

I have an old video, where I've practised with a knackered frame - I have a lot of those. And I can join frames at my table. And can make 5 or 6 frames in a day.
Anyway, this why I v-nail upside down.

[Justintime]

Ah OK that makes sense now. The Ulmia clamps are great. Have you tried a strap clamp like a Stanley, and pinning while clamped if that's possible with your tool?

[Gillthepainter]

Ulmia, that's the name. Their only downside is the clamps do move over time, so that they develop a wonky bite. With the potential to kink the wood join if you are not careful.

Justin, I've just found this set up that I've never seen before. And fancy giving it a go.

https://www.axminstertools.com/veritas- ... ggQAvD_BwE

I have 4 stanley straps, yes. But do get a bit of movement.
I use them mostly now for testing my chops before gluing, making sure my picture fits well without falling through - I have a tendency to chop too big so that I can chop smaller (add 5mm instead of 2mm sort of thing). I find that I get movement to my corners - which I do not get with the Ulmia clamps.

I've tried suing these belts without the corner pieces too, just as a belt. I shall persevere and find a way that works for me. I shall also report here if I buy the veritas in the link I've just given after looking at the reviews ...

[Justintime]

It feels like one of those situations where without being able to see exactly how you work it is very difficult to offer useful advice. All the clamp types are designed to give a similar type of pressure if used correctly. I think regardless of the type, if you apply too much pressure from the top or bottom during underpinning without sufficient support to the moulding you will see some movement. When using a strap clamp with its corners (and some card between the plastic corners and the moulding to prevent pressure damage to the moulding) you can tighten it until you hear a higher and higher pitch if you strum the strap allowing a considerable amount of pressure as required.
I don't see an advantage to the axminster clamp over a strap clamp Imo.