Which type/brand of razor blades stay sharp longest? (cutting card/greyboard)

Eze lap diamond hones. Availiable from many places on line  I used the red 600 grit, had it a long topime didn’t know if it was still available but just found out it is and about the superfine at 1200 grit  .....must get one!

Any cutting tool including kitchen knives which reflect light and the edges shine are blunt it’s the easiest and most common test Nothing as sophisticated as a samurai sword All edges are rather same, including milling cutters and lathe tools. Esp hs

Edited By Zan on 28/04/2021 00:22:02

Edited By Zan on 28/04/2021 00:25:34

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.

Zan.......plus 1.........on my second red eze-lap after 40years!....nobody on this site should be without one!!

..........did’nt know about the 1200 one either, but will order one today!

I’ve not read the topic but I use Swan & Morton no.3 scalpel and touch up the current blade on the red eze-lap two or three times before changing to new blade.........

Edited By Bob Stevenson on 28/04/2021 09:39:58

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

Paper and particularly cardboard are very abrasive on cutting edges -- as you have found out! It will chew up the very fine edge on a scalpel made for cutting soft human tissue. Its not so much a matter of the blade material alone as also a factor of the acute angle on the scalpel edge. Makes it very sharp but not very wear resistant. For extended work, the carbide Stanley blades look like your best bet.

But what removes a super sharp edge can also restore it. You can use cardboard as a strop to sharpen a scalpel edge.

Rotary Cutter vs Scalpel

I have been trying to research rotary cutters.

1. So, if I understand correctly, a rotary cutter has a very sharp blade in the shape of a wheel that freely rotates as the user drags the cutter over the material to be cut.

2. Compared to a scalpel blade, this has the advantage that there is no dragging of the blade past the part or material (which is important when cutting something like a woven fabric), and it cuts vertically with compression rather than with a slicing action.

3. The down-side is that it requires a solid surface underneath the part that is being cut. Also, unlike a scalpel, a rotary cutter won't be able to do sharp changes in direction.

4. From what I can see, something like my "Logan 350-1 Compact Elite" may not be able to handle a rotary cutter because there is a trench underneath the cutting guide:



...But I suppose you could insert cutting mat underneath the guide. But if you do all that, you start to wonder why your're not just using a ruler, no?!

Meanwhile I have now ordered some a Stanley Knife, with carbide blades.

It is possible to sharpen a rotary cutter e.g. using "Eze lap diamond hones" ?

Edited By John Smith 47 on 28/04/2021 12:20:00

Hello,

I haven't used a Logan Mount Cutter, but I have a Longridge one. You are advised, by Longridge, to always place a "SprintMat" under the Mount Board you are cutting. This is a specialy made board, designed to save the blade, stop it wandering off course and stop the Mount Board from breaking out. Does the Logan one not use a similar sacrificial board?

Mark.

Not for vertical cuts, when doing the actual angled cut then a sacrificial board should be used.

What cutter depends on material thickness and hardness. I use all three for card, scalpel, rotary cutter (Rotatrim) and mount cutter. A mount cutter will cut vertical or angled through thick card used for mounting things to without any further framing, so probably 2mm +. Rotary trimmer will cut through mount board but is better for 1.4mm than 2mm as well as paper etc. A scalpel will cut through most card thicknesses (including fingers), but difficult to control to get a good edge without repeated low pressure cuts and guidance.

Yes, Logan recommend the use of a sacrificial piece of board underneath the board you are cutting, but they only do this for when cutting angled cuts.

What was deeply irritating for me was to discover that the angled cuts don't actually cut at 45° ! For some reason (deeply irritating for my purposes) the cutting angle is only 38°.

@Mark Easignwood - Do you think that there is anything SprintMat or do you think my cheap hobby-craft matt would do just as well?

Hi all, firstly my grandfather, a butcher by trade never picked a knife up without sharpening with a steel it in a ritual resembling a sword fight, moving on, during our aeromodelling days we stayed on top of scalpel & single edge razor blades by honing with a piece of wood with wet & dry paper (silicon carbide grit) stuck to it, a wizard wheeze I learned was used by bookbinders to keep their home made cutters up to snuff, these days I have certain blades such as deburring 'twirly' tool blades that I frighten with few stokes of a fine diamond file, sets of which are dirt cheap, it is a good idea to black the cutting edge with a felt pen so that you can see that you are aiming at the right place!

BobH

So to those of you who like to sharpen a scalpel blade with some kind of diamond hone (e.g. @Zan, @Bob Stevenson...)

1. In practice, how many times can you sharpen a scalpel blade?

2. Are you using little sticks like this?

Or more like a big double-sided 'stone' like this?



3. Is there a special technique? How long do these hones last?

Personally I've not had much luck with diamond hones on knives (I've not tried scalpel blades). They seem to wear out on me and stop working. But maybe my technique is wrong (e.g. I am pressing too hard or moving the steel too fast...?? .

I am all too aware that sharpening sharpening is something of a dark art, because at a microscopic scale, sometimes you aren't removing material, you are just bending the point back up, and possibly serrating it. But a slicing action - with lost of sideways movement obviously works slightly differently purely vertical chopping action. 

Having spent some of my mis-spent youth overseas on an Island in the North Atlantic filleting fish I can tell you that I wasn't very good as sharpening filleting knives, but that the old boys seem to have this magical touch.
But whether this magic is required for scalpel blades I know not.

J

Edited By John Smith 47 on 29/04/2021 11:54:08

John , just a thought , but since they are doing it every day , what cutter/backing mat / method of use combination does your local frame shop use ?

Re: Worn out Diamond stones: Try cleaning them. Something like WD40 and a toothbrush. I use diamond stones all the time in the workshop, and whilst I have worn them out it takes years of use even sharpening carbide and HSS tooling. But they do clog up.

Dave

Mount cutters can be had with a guide rail, stops and slotted base board, as per John’s photo. The slots in the base allow the blade to fully pass through the material being cut. The stops limit the horizontal travel along the guide, usually used for cutting windows in photo mounts. Cuts can be made vertical or angled, about 45deg depending on the blade holder used.

john smith 47.....seveeral points to make;

1) Yes those are the 'eze-lap' hones,...I have used the red one for 40 years

2) There is no 'special technique' to sharpening other than the two crucial factors namely keeping the blade at the right angle to the abrasive,...using small light circular motions.

3) Sharpening is NOT a dark art!......the final iteem in sharpening which is overlooked by many is to 'pinch' the edge between thumb and forefinger and pull off of blade.....if your fingers detect an 'edge' one side then you have NOT properly sharpened the blade but truned the blade edge....always test for this and carefully remove by light honing/stropping etc.

4) remember that many disposable blades are actually laminated so frequent resharpening quickly goes thru into softer laminations making the blade more or less useless and needing to be changed

5) Softer metals including most stainless steels are poor at both holding and edge and being easy to sharpen because of te3cdancy to 'roll the edge ' easily.

6) for fine cutting you need to use a smooth stone to give a keen and smooth cutting edge,..so, better sharpening kit than for common pocket and workshop knives.........for very fine edges such as razors you need a razor stone used with soft soap as a lubricant,...then careful strop on leather impregnated with a very fine abrasive such as Autosol etc

7) Zan is correct that you should not be able to see the cutting edge on fine cutting blades....use a glass to examine the edge.........fine blades work by separating the work smoothly.....if a rough stone is used it results in a 'saw' type edge which rips the workpiece

8) I resharpen my S&W no. 10 & no.11 blades a couple of times using red eze-lap, then fit new blade. For larger blades I use a 'DMT' diamond sharpener, which is similar to eze-lap but much larger.

9) keeping diamond hones/laps clean is essential......my new red eze-lap is definately more aggressive than my 40 year old one despite frequent and careful cleaning although diamond hones are not supposed to wear.

The ones that stay sharp the longest are the ones that don’t get used!!

My scalpel usage was nearly always surgical. Little difference between swann morten or paragon blades. One of the factors here may be shape of blade. Whilst i concede that a pointed blade may be necessary for 'nipping' out sharp corners it's use elsewhere is likely focussed on a small proportion of it's length. Surgically I almost never used them preferring a convex curve for a smooth incision and the natural change of hand postion causes one to use varying parts of the edge.

And just in case anyone is unaware blades were available sterile and single wrapped or non sterile wrapped in multiples which i assume is cheaper

For hobby use its probably worth having 2 or 3 handles preloaded with different shape blades.

pgk

Sorry I have not been able to be on the forum for a while.

Your understanding of a rotary cutter is much the same as my own.

the main advantage I see is that you get a longer effective blade as in Pi x D so longer life, there must be something in that as many office type paper trimmers use rotary blades.

Similarly to Trevor Drabble I see liknesses to professional framers picture mounts, have you investigated suppliers of that equipment?

I cannot see a rotary cutter working too well on the internal corners and some sort of accurate guide system would definitely be needed.

My rotary cutter works fine using a green mat under the object being cut with a straight edge for guiding (no precise stuff).

I guess a cutting wheel could be mounted up and sharpened but my usage is more limited so I would probably buy a replacement wheel when eventually needed.

Hope you get on well with the new Stanley type blades.

Edited By V8Eng on 29/04/2021 15:40:47

Edited By V8Eng on 29/04/2021 15:42:07

Edited By V8Eng on 29/04/2021 15:42:59

@Bob Stevenson - "Sharpening is NOT a dark art!.."
Well, so you say. Pulling the shape edge off between finger and thumb.... crikey. Do you mean unprotected, with your bar skin? TBH, I am feeling rather intimidated by all that. I'm not sure how the heck to even keep the blade at the correct angle ==> I think I fail right at the starting blocks!

Does anyone know of any really good explainer videos on the likes of youtube? Maybe some of you have even made videos yourselves??

I now have the new Stanley carbide blades. Seem OK but not spectacular. I re-googled and it was interesting to see than I could find no other materials that commercial scalpel blades are made out of other than steel. Presumably there are good reasons why carbide doesn't work well on scalpels even if Stanley doesn't seem to be paying any attention to them.

[ADISE: Fwiw, from my days in science (c.30 years ago) I can tell you that the sharpest blade in the planet is (was) freshly broken glass. We used it to cut up slices of tissue for electron microscopes. However being technically a liquid glass doesn't hold its super-sharp edge very well. At the time the best blade you could get was diamond. I have no idea how they ground it. ]

J