morso pushing

[elly-d]

hey,

ok so, i have searched for this problem and not really found an answer.

my morso (when cutting hardwoods) is pushing the moulding as it cuts making for horribly gappy mitres. could this be just blunt blades? or something else? i didnt think that i had been using the blades for too long.

thanks.

elly-d

[easypopsgcf]

Could be 1.Blunt Blades
2. Rebate supports not at correct height
3. Blades not "Hollow Gorund"
4. Taking too big a bite?
5. Debris on the morso(means the moulding doesn't sit perfectly flat)
6. Warped moulding?

More than likley blunt blades though

[misterdiy]

Hi Elly

It could be any of the above, but I have had problems with new blades cutting ash. I find that it has to be nibbled at one notch at a time, but now I use the chop saw which gives a perfect joint

Steve

[Graysalchemy]

Warped moulding always causes a problem for me. I don't use a morso as I use a cassese saw so most of the above don't apply but I still get problems from warped moulding even expensive Larso Juhl !!!!

Hollow ground morso blades do make a difference though.

[prospero]

Sounds very much like blunt blades to me. Have you been cutting moulding with hard compo? Some of this stuff will take the edge off the blades in just a few cuts.

[BaBaZa]

I'd say blades not properly hollow ground.

Take them off and lie a credit card along the bevelled edge. If you cant see a little daylight then then they have not been hollow ground.

[Nigel Nobody]

Blunt blades would be my guess as the main culprit, especially if it wasn't doing this previously. I test my blades for sharpness by dragging a fingernail across the edge, at about 60 degrees! If it grips, the blade is sharp, if it slides, the blade is blunt.

I also find that with hard wood, taking tiny bites will also cause the problem.

[SPF]

Morso blades should always be hollow ground. As the guillotine cut is a 'pressure cut' the timber needs to peel away from the blades when cut to avoid 'pushing', if the blades are flat ground some degree of pushing will always occur. To elimate the chances of pushing:

1. Blades are hollow ground
2. Blades should be re-honed if any 'burr' is present on the leading cutting edge. (as a rule I always re-hone after they return from the sharpeners using a fine oilstone folowed by a leather strop).
3. Make sure there is no debris on any faces of the Morso.
4. Ensure rebate supports are set square to the moulding.
5. Apply firm pressure down on the moulding when cutting.
6. Cut the moulding in small increments, do not bite off more than it can chew!

May I recommend the use of Gorilla glue for hardwoods as this expands and fills any slight floors in the joints ( downside is this glue can be quite messy if too much is applied ).

[elly-d]

hi guys,

thanks for the replies.

i always get my blades (made by morso) shapened at lion, and i get good results from them. i haven't had this set on long but i guess something must have blunted them sooner than normal. my bad for not having sent the other set off for sharpening weeks ago so now any hardwood ones will have to wait a week, and just before christmas too.

i am coming round to the idea of saws instead of morso, but for money and space issues i will have to stick to my morso for now.

expanding glue in mitres? is that a good idea?

cheers.

[prospero]

Gorilla Glue. It that polyurethane? I only ask because I tried some once and it does stick like the proverbial. The only drawback is if you get a bit oozing out and don't clean it off before it sets. I used it for joining the sections of stacked frames. Never used it for mitres. Another problem I found is that I found was if you use the stuff in pump cartridges, it goes soild in a matter of days once you open them. And it's not cheap enough to waste.

[silvercleave]

is 'Morso Pushing' the latest Olympic sport??

[framemaker]

I am a big fan of using polyurethane glue, on all barewoods and with care on some large and chunky finished mouldings.
I think the expansion can be a good thing on oak and ash where a simple, natural, or clear, wax finish will be used. I used to find with PVA that just sanding these frames caused the mitres to open up, let alone fitting in the glass etc and pinning in with a fletcher gun. Whereas with PU the joints are so much stronger.

[Howard]

Hi all,
Something I have noticed with Wessex mouldings is the outside face of the moulding and the bottom face are not quite square so that when you pull the moulding against the guide fence and cut the mitre,particularly with deep rebates, and then transfer the moulding onto the underpinner and sit the moulding on it's bottom face to underpin there is a small gap one end of the joint.

[Not your average framer]

Hi Howard,

I would respectfully suggest that this may be a bit of a sweeping statement concerning this particular supplier and perhaps there is a better way to put things and get help and advice from the many highly experienced and helpful framers on this forum. You're not the only one who finds joining deeper moulding a difficult matter. There's a lot of technique in avoiding gaps in the join, such as:

1. Where you place the wedges

2. The choice of wedges used

3. Some deep rebate mouldings work better when using a band clamp while underpinning

4. Some underpinners don't have adequate rebate clamps

5. Low budget underpinners without a rebate clamp require a lot of technique to avoid gaps in the mitre when joining deep rebate mouldings.

6. Sharp Morso blades and a well set-up morso are essential for deeper mouldings.

Personally as a framer who buys bargain bundles, clearance mouldings, which often include returns and less than perfect mouldings, there's very little which prevents a perfect join if your equipment and technique is up to the job.

[SPF]

I am a big fan of using polyurethane glue, on all barewoods and with care on some large and chunky finished mouldings.
I think the expansion can be a good thing on oak and ash where a simple, natural, or clear, wax finish will be used. I used to find with PVA that just sanding these frames caused the mitres to open up, let alone fitting in the glass etc and pinning in with a fletcher gun. Whereas with PU the joints are so much stronger.

I agree,as long as the glue is applied correctly no problems occur. What I do tend to do on hardwoods which may be considered a bit 'belt & braces' is to pull masking tape across the mitres until the glue is set, this is especially helpful for deep box mouldings.

[Graysalchemy]

The talk of using PU glue and choice of wedges is all very important, but if you don't get a good square cut in the first place then, even if you manage to get the frame to joint perfectly with no gaps you are likely to have an uneven frame.

Start with the basics, make sure you have good moulding which is not twisted, then make the best possible cut then joint with glue as best as you possible can. If you don't have a perfect cut in the first place what you are doing from then on is, to put it as politely as possible, try to make good out of a bad job, or put it another way you can't make a silk purse out of a sows ear.

I would say that the quality of moulding has decreased over the last 10 yrs with more and more twisted moulding. As I have said before even some of the Wide Larson Juhl mouldings are coming through with a slight twist.

Cheers

AG

[Not your average framer]

Hi Howard,

May I suggest a little troubleshooting to see why this deep rebate moulding is not going together as you had expected.

If you cut a frame with this moulding and just assemble it together on a flat work surface without any attempt to glue or pin it together, does it fit together without gaps?

If there are no gaps, then there is no problem cutting the moulding on your Morso. This implies that both the moulding and the Morso are O.K.

If there are gaps, you need to check you Morso blades, your technique when using the Morso and finally the moulding.

If there is another forum member near you, then you may be able to get another frame cut on the other members Morso for comparison.

If all is O.K., then time to think about joining the moulding. This is where even the experienced framers will admit that there are many pitfalls which can occur when setting-up and using an underpinner to illiminate problems with difficult mouldings. We all can fall foul of things which can catch us out from time to time.

So here's an off the top of my head list of things to check:

The top clamp - Is it set to the correct height? Is the clamp pad clean, free of excessive wear and build up of glue?

Are the fences accurately set and free of build up of glue?

Does your underpinner have a rebate clamp or it is a budget model which does not have one? If you don't have a rebate clamp, then consider using a band clamp around the complete frame prior to underpinning, or clamping and gluing the frame first and underpinning it after the glue has fully set.

There are different methods which are favoured by different framers - The right method is the one which works for you!

If all else fails then get your suppliers rep to have a look and perhaps ask the supplier to do a test join for you of their own equipment.

As you will know this supplier does not do budget type mouldings, they also have a well known moulding manufacturer and a framing school in their group. Not only would I expect them to correctly join the moulding without problems, but they may also be willing to help you to discover how to achieve the same results yourself.

Stick with it - These are things we all have to work at, but we do get there!