Morso Blades - Again (yes, sorry)

[StevenG]

Hi Guys

I know this has been covered before many many times but I just need a little more....

I just got back three sets of sharpened blades and all three push the moulding away (left & right) as the blade comes down. The issue is more apparent on wider mouldings. After a cut I can see that the edge of the moulding nearest the fence is perfectly flush with the bottom knives but as it goes back a gap appears between the bottom knife and the edge of the moulding (the width increases as it goes back). I can even feel the moulding being pushed away as I cut it.

I've made a work of art to help in the explanation, hopefully everyone can see it.

I suppose what I'm really asking here is .... apart from all 3 sets being sharpened incorrectly is there anything else that may be causing this.

I've tried several different mouldings, with and without rebate supports. I've tried even with only the left blade attached (don't ask me why) Is it possible I can be putting the blades on wrong. I make sure the bottom of the blades are aligned and there are no gaps at the front. Actually, the blades do appear to be sharp enough and as far as I can tell they're hollow ground (I've placed a blade from my mount cutter across the edge of the Morso blade and there's a curved gap beneath)

Cheers

(Needless to say I'm at a standstill here )

[GL@profile]

Hello,
You need to get your blades "hollow" ground.
All the issues you are incurring sound very much as if your blades have been "flat"ground.
Do not send your blades to a sharpener who doesn't know the difference between hollow and flat grinding.
I hope this helps.
Good luck Guy Lambert (Profile Mouldings Ltd)

[prospero]

What he said. ^

[JohnMcafee]

This is almost certainly caused by movement.

During the cut either the cutting head is moving back - away from the fence or the moulding left of the blade is moving to the left as it is being cut.

To test this, try clamping the moulding securely to the left fence and also, on the final (small) cut, ensure that the cutting head is forced fully forward and rigidly kept in that position.

[StevenG]

The blades sharpened incorrectly??? Hmmm, that's what I thought too but 3 sets!? One set was brand new (ish) - 1st sharpen. Anyway, I've called the company and they're picking them up for a look over. I've ordered another new set just to prove a point (if it is the sharpening process). The insist they've been hollow ground, oddly though when I quoted from the Morso manual on grinding angle etc they were interested in the details, and wanted a copy as they had nothing - didn't fill me with confidence though But they're been doing this blade sharpening business since time began so I can't argue. What I know about that side of things you could fit in something so small there's a good chance you mightn't see it.

Anyway - John, it certainly is movement of some sort, I've been shaking my Morso, adjusting bottom knives etc etc and everything is tight. I've done what you've suggested and clamped a piece of troublesome moulding and cut it & it didn't move (it couldn't ), when I examined the cut on the moulding it still wasn't flush with the bottom knife but not in the same way as before though, this time there appeared to be about 1mm overhang. What I mean is that the moulding (on the left) was about 1mm to the right of the bottom knife - the overhang did seem to be uniform though from the fence edge to the back. What do you reckon that means? I've been at this all day and my mind is worn out

Thanks for the replies

[IFGL]

They got the angle wrong and sharpened all 3 on the same setting.

[Not your average framer]

If there was not anything wrong before you had the blades sharpened and then there was something wrong after the blades were sharpened, then it will be the sharpening of the blades that will be wrong!

Not every company which sharpens blades know how to sharpen Morso blades and some of the framing suppliers are better at sharpening Morso blades than others. I had to find this out the hard way and having tried several framing suppliers which sharpen blades, before finding one that knows their stuff, I can easily understand the problems this causes.

[simoonez]

Get them sharpened at Mainline then you know they'll be as good as they can be.

[StevenG]

Well the majority vote here seems to point at the sharpening process which apart from wasted time is easily sorted (hopefully). The problem with being in N Ireland is we're limited on options. I'm sure mainline etc are excellent but I've been quoted around £70 pet sharpen - the carriage is a killer. Anyway, I'll update this next week & thanks again for the input

[JohnMcafee]

when I examined the cut on the moulding it still wasn't flush with the bottom knife but not in the same way as before though, this time there appeared to be about 1mm overhang. What I mean is that the moulding (on the left) was about 1mm to the right of the bottom knife - the overhang did seem to be uniform though from the fence edge to the back. What do you reckon that means?

It means that the moulding must have moved by 1mm subsequent to the cut. However from what you say it appears that when the moulding is clamped the Morso cuts an accurate mitre.

Did you make a test frame?

[JohnMcafee]

...make sure that you push the head forward all the way and hold it firmly at its limit of movement as you make that final cut, this should take care of that 1mm overhang you mentioned.

[StevenG]

Hi John, the overhang is still there even after trying to 'slice it off" with another cut, I didn't make a test frame actually - From experience this only leads to wasted moulding and as I said earlier it's more evident on wider profiles & that equals the more expensive stuff I did try and find some 3x1 for testing but they only had 2x1 and the issue isn't too bad at that width and........ it doesn't seem to be as bad anyway on softer woods.

Today I will mostly be cutting mounts & glass

[prospero]

I had this once when I tried to cut some wide moulding with big ornaments on it. The 'gesso' was the hard resin type. It blunted the blades to such an extent that I had exactly the issue you describe. On subsequent cuts the blades failed to take a true track though the cut and the cut faces were waaay off.

Your best option now is to send one set to another sharpener and see if they can correct the blades. They may need an extra deep grind to put them to rights.

[A Few More Words]

We once had a similar experience , as described...we first suspected the blades and then the operator...but it turned out that it was caused by "looseness" of the knife block.

Looking at the photograph, youll see that the knife block is moved in / out along a "dovetail" type slider as you cut the moulding. This sliding fit will wear slightly over time and so the knife block assembly will be free to rotate slightly...so that when you press down the pedal , the knife block may not move exactly truly vertically over its length of travel.. this will particularly manifest itself on heavier profile mouldings, pushing the moulding away from the blade etc.

Viewed at right hand side

Morso Knife Block.jpg (1.87 MiB) Viewed 11364 times

Park the knife block so that the dovetail slider is centred , while the knife block is raised (like in photo)...then just grab the top of the knive block and try to rotate it in both directions.....if it rocks too muck it may need tightening.

To tighten , park the knife block as in photo and slightly slacken off the qty 2 6mm allen head bolts. Then tap the block with a hammer to snug it up against head slider, and then nip up the 2 bolts again. Test for block rotation again....you should see a difference.
If you cannot get it snug enough by doing this on one side...you may need to do other side also...but only loosen one side at a time.

If the knife block is loose, allowing this rotation movement and you do proceed with tightening it up...you will certainly notice a big difference in cut performance straight away....and it will just take a few minutes to do !

Hope this may be of help.
Tom

[DEEPJOY]

Hi

Thank you for posting the adjustment info on the Morso. I am struggling with this, I have checked mine using your technic and yes I have movement when I twist the head. There is a dove tail slider on both sides so adjusting one will have an effect on the other side surely. Also, is it possible to knock it out of alignment by doing this?

What is the acceptable movement when twisted?

I do not understand the bit when you tap the head with a hammer/ Tapping it to one side will expose a gap on the other side slider.

If you loosened both sides does the head self centre? Then is it a case of pushing both sliders up to the head but still leaving enough of a gap so the head moves freely forwards and backwards?

[StevenG]

Hey Tom, that's some good advice right there. I'm not in the workshop at the moment but the second I'm back it'll be the first thing I look at. It could be a combination of that and an issue with the blades as it seems to be more problematic on 'harder' mouldings. I've never touched those bolts in the 4-5 I've had the 'machine' - good tip, much appreciated

[A Few More Words]

I just wrote another post ...and then It disappeared when I hit submit !

Anyway.....to clarify
Can only speak on our own experience,

We had problems with larger and harder mouldings......joints open at inside when joined / moulding backing off from blade when knife brought down cutting etc.

Check for sloppiness of knife movement.......with head raised, grab it with both hands and try to rotate to / fro...observe rocking in dovetail sliders.

To fix.. with head raised, and centered along dovetail slider (to ensure you keep dovetail block parallel) .loosen the qty 2 allen head bolts ...just slightly....then tap this short dovetail block inwards (with hammer) to snug up the dovetail slider.....nip up the 2 Allen head bolts again......recheck the head for rotation....it will be a lot less.

By only moving dovetail block on one side , no noticeable misalignment occurred.

Don't know how loose head was....but was certainly looser than it should have been.....due to normal wear and tare etc. You will notice the before / after difference ,

If the head is loose...this will be the first problem to fix.....as it wont matter what blades you install....you will not get a good consistent cutting result with the head too loose.

Worth a shot !
Thanks
Tom

[StevenG]

Quick update..... this certainly is a great tip but in this instance it didn't resolve my issue However, still, a good thing to know.

Thanks again

[kevin]

Lion picture framing are excellent at re sharpening Morso blades and no where near 70 quid.
A few years ago I was given the name of a company in NI.
I had your problem as result of using them.
I packed off said blades to Lion, excellent results with same blades, Good luck.

[StevenG]

Interesting....the new blades should be arriving today or tomorrow & I'll be surprised if everything doesn't return to normal with the new set, I'll give these guys another chance with the sharpening because they are incredibly convenient (if done properly). I'll give Lion a call later too, just see what the costs are.

Cheers
Steven