Materials that quickly dull an edge

K

kershawguy13

Gold Member
Joined
May 8, 2014
Messages
369
I cut some thick old carpet today with my plain edge Endura and when I was done there was no edge left. It wouldn't cut paper at all, and had a few small chips in the edge. Took me a while to bring an edge back with the SM and there are still a few tiny chips in the edge. What other materials have you found will quickly dull an edge?
 
You were mostly cutting sandpaper at that point with all the ground in dirt and gunk that carpet accumulates.

Chipboard can do a number on an edge as well.
 
The kind of shipping tape with the white strands in it will dull a blade quickly.

Sent from my SM-T710 using Tapatalk
 
Fire blanket. No more lending knives on the job. No have knife no need one.
 
Carpet, Linoleum , cement bags, shingles, salvage which is roll roofing. Valley tin or copper.
 
Materials that quickly dull an edge
Click to expand...

We just did this one here.

I was just thinking today about posting an edge that has surprised me how long it has lasted. So rather than start a thread I'll put it here.

My point is that I have never had to resharpen this bit once it was sharpened the first time and I have been using it occasional every year for like eight years. It has had plenty of use.

So cutting heat treated aluminum, and some of it fairly hard has been no challenge to the edges on this inexpensive steel bit. Probably like a two or three dollar bit.

I reground this woodworking paddle bit. I needed a reamer that was a touch over 8mm (8mm exactly was too small) so I ground the sides of this bit to the size I needed. The hole that is too small is about 5.5mm. I left the wider part of the bit unground and the transition area was radiused and sharpened so the edge of the hole is deburred and smoothed when the bit bottoms out on the radius. A rubber hose goes through this hole and sharp or jagged metal edges are not welcome.

I added a hex bit socket to the opposite end. I snap it onto a speeder socket handle and turn the reamer with muscle power. No real reason to use a power drill and I have more control with the speeder. It cuts plenty fast enough turned by hand.

Once the hole is reamed I snap the bit off the speeder handle and I can take one of the the sharp edges on the delta shaped point and use it like a carving knife to take off any areas of sharp edge on the hole on both sides. Works totally great.

The black thing in the photo is a rubber sleeve to protect the bit in the tool box.



 
Tar paper. I have never seen such carnage. I literally sharpened my BM940 in the car (wasn't driving) on the way to a job. We had to cut a bunch of strips of tar paper. I only cut about 5 before I realized i could just use a 2x4 as a ruler and tear it. However, the edge on the S30V blade was butter knife dull. I've carried that knife for 3-4 years every day (until recently, when I went knife crazy) and I've never seen it dull that fast.
 
Fiberglass insulation, cheap cardboard (full of abrasive filler), sheet rock, zip ties. An old knife maker told me, think of your knife as a kitchen knife, it is made for soft material, meat, veggies, etc. also cut on a wood cutting board, ceramic or hard surfaces will also dull it quite quickly. Yes with today's steels and thicker bevels we can push heavier cutting materials a bit further than a kitchen knife but it still was designed for soft non abrasive materials.
 
Fiberglass insulation is a beautiful edge's kryptonite!!
I had my VG10 FFG Endura gleaming and screaming......I cut 6" flex duct to size twice and I could have slit my hand without a care.
Tar paper, carpet and very thick cardboard have destroyed my edges also.
I now use my razor knife for that stuff.
Joe
 
Scotch Brite pads that are used for dishwashing or known in the metal-shop trade as beartex.

Kills a knife edge, much better off using scissors or EMT shears instead.

The EMT shears work well for cutting sandpaper too.
 
I can't say it's that easy....

It would depend on the steel and the hardness of that steel....also, to some extent the primary bevel/edge finish and geometry.

I have knives that dull from cutting cardboard (tough on knives) from a few large amazon boxes, and then ones that can pretty much cut the same material all day long...
 
My vote for fastest edge killer is fiberglass insulation and filter material.
 
My knives can never cut paper anyway. What dulls them fastest is whittling a brick with a delica so it'll fit in the gap you're filling. It always has usable edge after drywall carpet etc but not a brick nope


Sent from my iPhone using Tapatalk
 
We planted a few shrubs & a tree this Spring. Scoring the root balls on them before planting dulled my blade real quick.
 
I cut some new carpet the other day and that quickly dulled my edge. So it's not just the sand and dirt found in used carpet.
 
You must log in or register to reply here.
Back
Top