The Framers Forum

Hi everyone

After cutting two pieces of moulding with my morso I set them loosely on the bench to see if there are any gaps. I have noticed that if just place them together without glue or anything there is a gap all the way down. Its not as if the gap is front or back, its just a straight gap. I can usually remedy this using glue and pinning but was wondering if this is normal. Kind of hard to discribe what I mean. Moving the fences doesnt seem to help.

Thanks

If I understand your problem correctly it may be that the rebate supports are set a smidgeon to high resulting in a gap along the top of the mitre.

If you are able to post a picture of the issue more knowledgeable framers than me may be able to help

Peter.

Here is an example

This may be caused by different things and it's not always easy to figure these things out. Somethings you may need to illiminate other possibilities before you can determine the origin of the problem.

If you are using a Cassesse underpiner, at least some of the Cassesse models have the possibilty of the block which fires the wedges upwards being a little out of line with the suface on which the moulding rests when loaded into the underpinner. It may be a good move to check this and see if this is happening.

Later versions of models like the CS-88 are fitted with two pieces of white plastic to prevent the sliding plate under the fences to prevent the top clamp from deflecting this plate under the pressure to the top clamp pad. Earler versions never had this modification and over time distorted slightly to produce this same problem. This may not be the cause of your problem, but at least it one thing that you can look for and perhaps cross off the list.

If I understand right, the blades appear not to be cutting straight down but deflecting slightly - giving a cut that is
not perpendicular. I agree that the rebate supports are the most likely culprit. Try cutting a flat piece of wood without
a rebate. Bit of 2x2 or something with a bit of height and check the fit.
The only other thing I can think of is the blades not ground to the correct angle. Try another set if you have one handy.

*** FWIW the corner in the picture looks fine to me.

Is this a wood moulding, or a polymer moulding? With a newly sharpened blade there is not always any real difference between the results of cutting wood, polymer blades, but as the blades start to lose that edge a little, although they still cut alright, sometimes a very slight adjustment may be needed to the fences when cutting polymer mouldings.

This does not mean that the blades are anywhere near needing to be resharpened, it's just something that I have found can happen sometimes, but not necessarily with every polymer moulding, but I have encountered the problem on odd occassions without any obvious reason why.

The op states that this gap is there before the two pieces are joined so presumably no underpinner involved...
The illustration shows a flat moulding, so what happens if it is cut face down eliminating rebate supports?
If there is then a gap at the back of the join I suspect it's the blades not correctly sharpened

I can't see any problem here - if the photo shows two pieces that haven't been joined/pinned yet then isn't that the way things normally are??? What am I missing?

Aprreciate the replies guys. The picture shows unpinned unglued moulding. I just assumed that the two pieces should have a good join even before pinning..ie resting against each other. I will try cutting some lengths without the rebates to see if that helps. Will also try the other blades I have.

Here is another example

Thanks

featurepiece wrote:What am I missing?

You're not the only one! Me too!

I think you're overthinking it and making work for yourself! Gluing and pinning isn't so much a remedy to a problem as a procedure in the normal course of events. If the gap disappears (from both front and back) after gluing and pinning, I would consider it a job well done!

Some of you need to go to SpecSavers , I can see a gap, the op says they have put the two bits of moulding next to each other, I assume they are touching at the base (back of the moulding) where the sit on the bench, but there is a gap on the face of the moulding, a problem which can be caused by having the rebate supports adjusted too high so the moulding is leaning back, so the cut will not be at 90 degrees to the base of the mounding (as I was telling my part timer on Friday when teaching him to use the Morso) or the blades are worn , so are pushing away from the moulding when cutting, or rather the moulding is pushing away from the blades when cutting

Mostly to amuse myself, I've just made my first ever Youtube video on my iPad

On a flat surface I would expect a dry join to be as good as a finished glued and pinned one

Turn up your volume to enjoy the sound of oak... lovely

I think kuduframes had the right suggestion. On the flat moulding, turn it up-side down and cut it as before, and see what happens. We're all assuming that you make the final cut a shaving cut, so as not to create any movement of the moulding. Setting the rebate supports can often be a bit hit and miss, so it's important to hold the moulding down firmly and wall bedded on the base. Otherwise the moulding will tend to rotate a bit as it is being cut.

There are only two things that can cause a non vertical cut on a Morso,
rebate height set incorrectly (as a previous poster said)
or
your blades have been incorrectly sharpened/distorted.

Mark

"Some of you need to go to SpecSavers " mark that up as one of your best ones Steve

Seriously, I think we all would be just as concerned as the op if our mitres looked like that.

The consensus of opinion confirms the problem is rebate supports are a gnats whisker to high or worn/incorrectly sharpened blades.

David's Youtube sets a fine example and demonstrates what to aim at

Peter.

The video is exacly what I would expect but cant seem to achieve at the moment. Im away from the workshop currently so will give all the suggestions a go tomorrow and report back if anyone is interested.

poliopete wrote: Seriously, I think we all would be just as concerned as the op if our mitres looked like that.

Yes of course, if they looked like that *after* they'd been glued and pinned.

But the OP has said that after gluing and pinning, the gaps disappear. So what I don't understand, is why there's a problem if there are no gaps - front, back, bottom or top! - in the finished job. Would be grateful if someone could explain

If the gap is disappearing when glued and pinned, then the frame is cupping, so on a flat frame, if you lay a straight edge across the front of the frame, you will see the outter edges of the frame are higher than the sightedge, so you have turned a flat moulding into a slopping moulding. Like a lot of the problems on the forum, prevention is better than cure, learn how to set up your machines and tools, also learn how to use the said machines and tools, rather than trying to bodge up after the event, it's also saves time to get the mitres right when cutting than filling and sanding then painting , it only takes a couple of seconds to set the rebate supports to the right higth, than half an hour filling etc
That's all in a perfect world, I should listen to my advice one day

Is there anything on your morso bed? A paper measuring gauge perhaps?

Do you have a left hand extension on you morso, if so, check it is level with morso bed and it doesn't go higher than the bed.