Morso Blade sharpening (again)

[shogunswb]

I know this has probably been done to death but things change in who sharpens in what way & if they are any good or not,

Basically I used to have my blades sharpened by Wessex Pictures, it was easy, they delivered & I gave them the dull blades & they dropped them back sharpened the next delivery, happy days.

The thing is the people they used to sharpen the blades would flat grind them which from my perspective cuts way, way better than hollow ground.
Then they changed to a company that hollow grind the blades & they were crap. They took the blades back & re-sharpened but they are still crap.
Basically I find that with hollow ground blades it doesn't cut through the moulding straight but rather in an arc so when I go to move the head away from the moulding there is pressure on the blades pushing them back & when you put the two corners together they touch in the middle but there's a gap at the top & bottom & the harder the moulding the worse the gap.
When I first started I had hollow ground blades (sharpened by Lion) & they had exactly the same problem.

If someone is able to tell me why they are cutting like that or if I need to adjust the Morso in some way then I'll give it a try.

The other way is to find someone who flat grinds the blades.

[JFeig]

You might find this article from a knife manufacturing company interesting.
https://agrussell.com/knife-articles/bl ... arp%20edge.

Could your problem be with taking too large of cuts in the wood moulding? You have more precision with smaller (thinner) cuts.

This is who I use. http://hayesgrinding.com/precision-sharpening-services/
They have been in business since 1870 with the same ownership. All of their guillotine blades are hollow ground, (the printing industry, Zamboni machines for ice arenas, planer knives, etc. You don't stay in business that long by performing inferior service.

[shogunswb]

Thanks for the info, I’ll give it a good read.

As for taking too much per cut it doesn’t make any difference if it’s a thick or thin cut it’s almost like the cutting edge is so thin it deforming as it cuts and the harder the material the more it deforms.

Should probably have mentioned I'm in the UK.

[JFeig]

Yes, I understood that from the start as your location being "West Wales".

[Justintime]

Where I West Wales @shogunswb??

[shogunswb]

Rhydowen, SA44 4QE

[Justintime]

Not far then! (SA41 3TL).
Hollow ground are by their nature giving a finer cut than flat ground.
Maybe this will help
http://www.morso-guillotines.dk/resources/training.html
Are you adjusting the bottom knives when you change blades? There are so many possible variables...
I know what you mean about the wessex subcontractor for sharpening. Last year or the year before I swear I was getting blades back that hadn't been near a sharpener...
I was recommended a company in Cwmbran, Beverstock Ltd. They collect and drop off and come back perfectly (hollow ground) every time.
https://beverstocksaws.com/

[shogunswb]

I agree that hollow ground should be by its very nature be a better cut but I just cannot get the blades to cut straight.
Yes I've adjusted the bottom knifes & spent a long time making sure the blades are seated & lined up correctly.
It's probably something I'm missing as the machine was second hand (although barely used) so something might have been adjusted on it before I got it but I was hoping that someone else might have had the same issue & worked out where the problem lies.
Thanks for the training link, I had a look at it many years ago but I will have another look just to make sure.

[Justintime]

"... it doesn't cut through the moulding straight but rather in an arc so when I go to move the head away from the moulding there is pressure on the blades pushing them back"...
I can't make sense of what you mean?!
Do your blades look like this?

[shogunswb]

I’ll have to fit the blades and do a little video to show the problem.

[Mark Thornton]

If the blades feel to be getting tighter as you make the cut then it’s your blades that are warped so no amount of adjusting will cure the problem.

Mark

[shogunswb]

So I was doing the video to show the problem of the adjuster kicking back after the cut & I think I found the problem.

When I was trying to fit the hollow ground blades I just couldn't get them to line up so I took them off again & ran my fingers over the rear face that fits against the Morso head & there seemed to be very slight hills.

I got some very fine wet & dry paper wrapped around a small square metal block & rubbed it over the back of the mounting face of the blades & sure enough, specifically around the bolt holes I could see that it had removed some material & the other blade was the same.
Also ran the wet & dry over the Morso head but apart from a little bit of old oil that was fine.

Re-mounted the blades & still can't get them 100% true but they are very very close & even when I cut oak there is no problem with a warped cut.

I wouldn't say that the hollow ground cut any cleaner than the flat ground but that could just be down to the quality of the sharpening as I also noticed that the blades hadn't been backed off after sharpening so I also had to do that before fitting & one end of the blade was definitely sharper than the other end.

Just very glad to have resolved the issue, I hope.