8 sided frame

[stcstc]

I have been asked to frame some certificates which have 8 sides, ie the corners are cut off

I first suggested to the client that if we used notmal frames with 8 sided window mounts. but he doesnt want this

so he wants frames which have the corners cut off

anyoe done this before?

if so how did you cut the joints / join the corners

i was thinking of using my mitre saw and mitre bond glue as i dont think an underpinner will work

[Bill Henry]

I’ve only done it twice, and it was a real bother.

If you’re using a Morsø, each miter angle needs to be 67-1/2°(45 + 22.5) rather than 45°, but is difficult to set precisely enough with a Morsø. And, your rebate support won’t work at those angles.

If you use a saw, your “protractor” scale may have a détente on it at 22-1/2°, so it will be a bit easier.

If you have a miter sander (I don’t), you most certainly will have to use it. If not, you may need to do some trial and error, practice cuts.

Because any two adjacent rails are not at a 90°, you can’t use a vise – unless it is adjustable – so you will have to come up with a clamping or strap gizmo.

Like I said, it’s a real bother. I won't do another one.

[Not your average framer]

O.K, I've done a few and it can be done with a Morso and underpinner, but you need to know how and you need two special templates. The first template rests against the face of the Morso blade to give you the correct angle to set the fence relative to the blade angle and the second template is an adaptor to fit the 90 degree fences on your underpinner. This drastically reduces the range of adjustment for placing the wedges when joining the mitres - sorry there's no way or getting around that one!

I made my own templates from wood, but I have a vernier protractor to help me get it right. These days a vernier protractor is not too expensive from some tool suppliers.

Three more problems:

The measurement system on your Morso is designed to be correct for 45 degree mitres. The fences on your Morso normally are a nice snug fit with the Morso blades and therefore stop the back of the moulding from tearing or splittering. Finally as already mentioned the rebate supports no longer reach to where they need to be, because they are not suitable for 8 sided frames.

O.K., three answers for the above problems:

Sorry, but you now have to do your measuring by another method. I cut mine over size and accurately measure how much I need to take off and carefully shave it down to the correct size. I cheat a little by using two bits of masking tape, one is stuck onto the face of the fence and the other on to the moulding (if the surface finish is safe to stick masking tape to), then marking a reference line on each bit of tape and working from these marks.

Next you need to extend your fences by placing a flat section of wood between the fence and the moulding. Important - make sure that you allow for the added thickness in your calculations.

Insert a flat section of wood in place of the rebate support, so that you cut through the moulding and wood support section at the same time.

Really accurate measuring equipment will help a lot, so think about getting a vernier or digital protractor and vernier or digital calipers. I use both and I'm glad I bought them!

It's a fiddly job, it takes a lot more time than a normal frame and there will be more wastage than when you make a normal frame, make sure that you price the job accordingly.

[stcstc]

guys thanks so much

i am glad its not something i was attempting that was too silly

[framejunkie]

Having tried it both ways I'd recommend using a good quality mitre saw over a Morso. Be aware that you'll probably need to tidy up the cuts by sanding if you want really crisp joints. Its all fiddly and there'll be a certain amount of trial and error, but charge extra for the hassle factor and it won't p**s you off too much.

I used to have an octagonal mirror up on the wall , but i took it down because people kept ordering them!

[prospero]

The last time I did 8 siders was for mirrors. I cut the pieces oversize on my trusty old Nobex saw and shaved the mitres on the Morso. Getting the angles perfect is the hard part. There are 16 faces. If one side is a whisker out, the error is multiplied x8. If both sides are out....... well there is always the possibilty that one error cancels the other. But it's a fiddly job and the wider the moulding the more angle errors show up. Of course, once you get the angles calibrated you can knock them out all day. There is also the problem of not being able to use the Morso measuring stops, so a bit of improvisation is called for.

As for joining.... You can underpin 135deg angles. You can knock up a temp 135deg fence from wood that slips in front of the std fence. If it was a wide chunky moulding I would biscuit the joins and strap clamp the whole thing.

[Not your average framer]

The last time I did 8 siders was for mirrors.

In my experience all of the eight sided frames I've done have been for mirrors. I've even done the odd one or two for display stock and they are very popular.

Of course, once you get the angles calibrated you can knock them out all day.

Peter is quite correct, it is a simple matter to knock them out all day long and setting up the Morso to cut the correct angles is the main issue to solve. Once you've done that, the rest is easy.

For those who don't know about vernier protractors, the markings on vernier scale don't quite line up with the spacing on the main scale, so as you move the vernier scale relative to the main scale, it will line up in different postions on the two scales, so that you can measure very small angles of arc. A vernier protractor can accurately measure down to seconds of arc, so that accurately setting up the angle on your Morso becomes a relatively simple matter.

You can knock up a temp 135deg fence from wood that slips in front of the std fence.

This is exactly what I did, is made of two pieces of flat pine, which were cut on the morso and the joined on the underpinner. I was looking for it the other day, but can't find it. When it comes to light, I post a picture.

If it was a wide chunky moulding I would biscuit the joins and strap clamp the whole thing.

That's a very good idea, unfortunately I'm not set up to do biscuit joining, so I can't do this. It is however worth pointing out to those who haven't done 8 sided frames that the temporary fence which fits inside the normal 90 degree fences, also means that the normal range of position adjustment for placing wedges is very much reduced and on even moderately sized mouldings you won't be able to position your wedges as far from the back of the moulding as you might wish.

Therefore biscuit joining is probably the best solution to this problem.

[Bron]

I've done eight sided frames, usually to cut into Tondos, milled after joining, for which I have numerous jigs. I've also had the luxury of knowing the joints were going to be under gesso. 22.5 degree cuts, joined with biscuits, using wooden screw clamps on each section, providing a surface for other clamps to pull the joints together. Keep joining til it's an octagon. With prefinished, and biscuits, it might be possible to just hand hold them for the few minutes till the biscuits swell, and a band clamp for the final join. I reinforce the joints by routing out a groove for a thin plywood spline to be glued into the back. More jigs.

I have to say, I have a lot of respect for framers who can join finished moldings credibly.

Bron

[Roboframer]

My (Euro) underpinner has adjustable fences - so I could join an eight-sided thing quite easily.

If Morso ever produce a machine that has the same (i.e. - the angle of the blades and the lower blades are adjustable) I may entertain the idea of a frame with more than four sides, or one less than four!

Until then - and unless my demand/desire for frames with other than four sides increases - stuff it!

[MITREMAN]

I used to have a really good contract making hundreds of six and eight sided frames for terrium bases.

The frames would be mitred on my electric nip saw with the rebate facing upward so the terriums just dropped in.

The moulding was about an 1 inch wide plain stained walnut I used to stain the ends on an ink pad with brown stain before joining.

I joined the frames with glue on my cassese under pinner using the six or eight sided inserts they just drop in front of the fenches to give the correct angle.

I take my saw outside to stop the dust going around the workshop, its ok indoors with good extraction for a few but when you get hundreds its a nightmare unless you have a dedicated dirty room.

I do a few frames with fancy tops mainly for mirrors.

You can cut multi sided frames on the morso, buy moving the left fence and using a rebate support timber, but it alot of hastle for the odd one.

Nip saws are getting so cheap now it worth buying one for the workshop, what you must do is buy a better blade with more teeth per inch then the standard timber blade that comes with most saws.
I have found alumium cutting blades, which have a differant angles on the teeth and more teeth per inch give a really clean and far better cut.

Saws are great for those undercut large gold section where the backs can break out on the Morso, yes you can stop break outs on the morso but a saw saves time and hustle.

Really good for general DIY around the house to.



MITREMAN