Having been involved in the Graphic design and Art business for a number of years the weapon of choice was always a 10A Scalpel, most trade customers would by them by the box.

What surface are you cutting on?

Edited By JasonB on 27/04/2021 13:26:22

Agree with Jason. Truth is razor sharp edges are delicate and don't stay sharp for long. Many ordinary materials like paper and cardboard are distinctly abrasive. I've never found better than Swann-Morton.

I use more Stanley-knife blades than scalpel sized, but same problem. For many purposes it's important to change blade frequently. In between scalpel and carpet-knife size, I use the type of knife where a sharp strip is notched so the end can be renewed by snapping the worn section off. They aren't suitable for everything.

Stainless blades don't resharpen easily, at least not back to 'as new' condition in my clumsy paws. They're disposable, buy in bulk and dispose carefully.

Carbon-steel blades can be resharpened but it's a fair amount of fuss. My microtome has a Carbon steel blade that has to resharpened often to keep it tip-top, it's a time-waster. A carbon-steel cut-throat razor is also handy for microscopy: it takes even longer to keep in good condition, partly because I don't have a suitable strop.

Easier to accept blades don't last and change them at the first sign of trouble.

Dave

Use a diamond hone to resharpen

They last for ever. I did this at school teaching A level graphic design. Saved me hundreds of blades a year. Even better  is at home where an Arkansas whet stone or leather workers type of lap ( leather strip charged with 4000 grit) to polish. Had one blade in for years

Ps do you use a self healing cutting mat?

edit…typo

Edited By Zan on 27/04/2021 14:10:05

Edited By Zan on 27/04/2021 14:10:53

If you just strop them on a piece of card you will get a little more life out of them.

I assume you are using a proper cutting mat?

Edited By norman valentine on 27/04/2021 14:55:14

I would prefer the Stanley type over the scalpel, they are safer to use on cardboard. Less likely to suddenly fracture and fire off a sharp projectile.

I buy Irwin bimettalic blades if I can.

I can understand the OP's frustration – why can a tool last for ages when cutting steel but not when cutting card, which is so much softer?

The difference is in the cutting edge which needs to be much thinner, ie have a smaller included angle, so that it will cut a soft material cleanly rather than just push it aside or tear it. A lathe tool might have an edge with an included angle of 80 – 90 degrees, so there is plenty of metal around and behind the edge to provide support.

A knife or scalpal blade might have an included angle more like 12 -15 degrees, so the actual edge, the only bit that actually cuts, is very thin indeed and gets little support from the bulk of the tool. The Japanese say that a sword edge is sharpened until it is "invisible", that is, until it is so thin it no longer relects light. I am not sure if this can be literally true but it does give the idea of a thin edge.

Also, after any use the edge will start to wear, and the effect will be more serious in the thin blade because there is so little material in the actual edge and it is soon worn away. With a metal cutting tool a little wear may not be so noticeable, the motor provides power and the steel being cut resists tearing until the situation gets worse.

Woodworkers have this effect too. A chisel is normally sharpened with an included angle of 25-30 degrees. But a worker in oak or an exotic hardwood may need to use 35 degrees. Those working in the softer woods can use as little as 17 degrees for a handheld chisel used with care (and not with a mallet), and may need to use this extreme angle to get clean cuts.

It seems pardoxical, but the softer the material being cut the sharper the edge needed. As has been said above card is abrasive and will wear knife edges quite quickly compared with, for example, knife edges used on meat or many vegetables.

Rod

Yes, Swann Morton 10A for card and paper.

I don't use much greyboard these days, but do use the much denser [and archival] millboard.

Since I can't realistically cut either type of board by hand, I use the Victorian boardcutter in the photo for doing so.

Its blade cuts with a shearing action, so thankfully it has a very different profile from the crazily sharp edge a guillotine blade has to have.

I don't often need to cut narrow/thin strips, but if I do then yes, I would expect a certain amount of curling of the strip, even if the grain direction of the board is parallel, as it ordinarily should be, with the long edge of the piece being cut; if the grain direction is at 90 degrees to the cut, the curling will be much more pronounced.

The curling can, however, be reversed quite effectively if the strip is very lightly damped and placed under a weight between pressing boards until it's completely dry.

One of the best features of the boardcutter, apart from the fact that it will cut through the full width of a 3mm sheet of millboard in one pass, is the foot operated clamp, which guarantees the board will not move while the considerable cutting force of the blade is doing its work.

I buy my millboard [branded Gemini] from John Purcell Paper.

Besides the boardcutter, I also have a fairly old Avery P640 rotary trimmer, which is very useful for paper and card as long as you don't try to cut through too much material at once. If you do, you will not only get a rough finish, but the material will tend to want to move during the cut.

If I was buying one of these kinds of table-top rotary cutters again, I'd probably opt for one of the Rotatrim Professional series of rotary cutters, which I've tried and which seem to be more robust than my Avery.

I've used those Stanley carbide blades, they're very good, though I've never used them repeatedly on the same material enough to give real analysis on how much better they are compared to normal Stanley blades, which are also good.

I would say they hold up a bit better than scalpel blades though.

John , In case you didn't know , the 10A blade is the lightest straight blade that SM produce and is designed for their No3 handle . If your handle is able to accept different straight blades , l have some larger ones available to fit the No 4 handle , as well as some to fit their craft knives , and if you PM me your contact details , l can supply a couple of each for you to try . Trevor