Both Double Cut Files and Single Cut Files

[Wamsutta]

What I don't understand is why do they have both double cut files a single cut files with each having their own three grades?

Seems like you would start out with one double cut file and then switch to a single cut file.

The way they have it set up, you would go through six steps and have six files!


Double Cut Files - *******, Second, Smooth:

https://www.crescenttool.com/all-to...03665nn-10-flat-double-cut-*******-file-boxed

03698NN 10" Flat Double Cut Second File - Boxed - Crescent Tools

Count on Crescent Tools to get the job done. Get the 03698NN 10" Flat Double Cut Second File - Boxed here.

www.crescenttool.com

03731NN 10" Flat Double Cut Smooth File - Boxed - Crescent Tools

Count on Crescent Tools to get the job done. Get the 03731NN 10" Flat Double Cut Smooth File - Boxed here.

www.crescenttool.com

Single Cut Files - *******, Second, Smooth:

https://www.crescenttool.com/all-to...files/08642nn-10-mill-single-cut-*******-file

08673NN 10" Mill Single Cut Second File - Crescent Tools

Count on Crescent Tools to get the job done. Get the 08673NN 10" Mill Single Cut Second File here.

www.crescenttool.com

08704NN 10" Mill Single Cut Smooth File - Crescent Tools

Count on Crescent Tools to get the job done. Get the 08704NN 10" Mill Single Cut Smooth File here.

www.crescenttool.com

 

[Ohio Andy]

The terms *******, Second, and Smooth refer to the coarseness or fineness of the teeth, which determines how aggressively the file removes material and the finish it leaves.

Double cut is faster with a rougher finish than a single cut file.

Is there overlap? Although I own a lot of files, I don't use them often, I inherited them. I expect differences based on brand and varieties and cute it the same way I view sharpening stones.

I may own a bunch, but I rarely use every grit in progression that I own.

 

[Wamsutta]

I have the first one on the list. The 03665NN double cut - *******.

That file flat gets with it! It'll remove steel fast!

But I'm assuming mower blades aren't very hard steel.

 

[dscheidt]

Files used to be a vital element in fabrication, and not just a finishing and emergency tool, as they are for most today. Like any widely used tool, there were lots of variations and special purpose versions. American pattern files used to be made in four grades, coarse, *******, second cut, and smooth. Today it’s unusual to see any but ******* and smoothing. (Swiss pattern go from 0 to 6, but some grades are rare today.). there also used to be a bunch of different tooth angles and shapes, most of which are not common in modern files.

To make a part, the craftsman would usually start with big coarse or ******* file, and then move to second cut and smooth files, probably also changing the technique used (draw filing gives a smoother surface than straight line filing). Final finish would be done with smaller files. And, if the part had curves, slots, holes, or other features, they would employ files for those as well.

 

[four.cycle]

^ Very early on, what made the reputation of a "mechanic" (prior to their being called "machinists") was how well they could use a file.
18th Century stuff. Long prior to computers, automation, power equipment, CNC machines.

 

[neophyte]

What I don't understand is why do they have both double cut files a single cut files with each having their own three grades?

Seems like you would start out with one double cut file and then switch to a single cut file.

The way they have it set up, you would go through six steps and have six files!


Double Cut Files - *******, Second, Smooth:

https://www.crescenttool.com/all-to...03665nn-10-flat-double-cut-*******-file-boxed

03698NN 10" Flat Double Cut Second File - Boxed - Crescent Tools

Count on Crescent Tools to get the job done. Get the 03698NN 10" Flat Double Cut Second File - Boxed here.

www.crescenttool.com

03731NN 10" Flat Double Cut Smooth File - Boxed - Crescent Tools

Count on Crescent Tools to get the job done. Get the 03731NN 10" Flat Double Cut Smooth File - Boxed here.

www.crescenttool.com

Single Cut Files - *******, Second, Smooth:

https://www.crescenttool.com/all-to...files/08642nn-10-mill-single-cut-*******-file

08673NN 10" Mill Single Cut Second File - Crescent Tools

Count on Crescent Tools to get the job done. Get the 08673NN 10" Mill Single Cut Second File here.

www.crescenttool.com

08704NN 10" Mill Single Cut Smooth File - Crescent Tools

Count on Crescent Tools to get the job done. Get the 08704NN 10" Mill Single Cut Smooth File here.

www.crescenttool.com

Single cut files are better for sharping stuff, and should leave a smoother finish.
Machetes and other field implements are routinely sharpened with files.
A single cut ******* file might give the ability to remove a lot of metal quickly, in case of a blade nick, but then give a finish smooth sharp surface if gently rubbed across the blade edge.

The double cut would likely remove material more quickly, but would be less likely to leave a sharp edge.

 

[ecotec]

I have the first one on the list. The 03665NN double cut - *******.

That file flat gets with it! It'll remove steel fast!

But I'm assuming mower blades aren't very hard steel.

You’re right, they are not. They would be a lot more problematic if they were. We would need more spares around, instead of just having to sharpen them.

I use a die grinder and a ROLOC flap disc.

 

[Ohio Andy]

Single cut files are better for sharping stuff, and should leave a smoother finish.
Machetes and other field implements are routinely sharpened with files.
A single cut ******* file might give the ability to remove a lot of metal quickly, in case of a blade nick, but then give a finish smooth sharp surface if gently rubbed across the blade edge.

The double cut would likely remove material more quickly, but would be less likely to leave a sharp edge.

So that crazy dull ax that I did not want to put on one of my machines to sharpen. I started with the double cut and I finished with the single cut file... Well before I moved on to something even finer mostly because someone I teach with said they wanted it sharp...

Then it was probably too sharp. So I made a leather case to protect people from the blade when not in use

 

[Wamsutta]

Ohio Andy,

Which file would you recommend for a brand new mower blade?

I would just need to remove the paint from the edge and true up the edge a little bit.

Trying to remove as least metal as possible.

 

[Beerhippie]

Ohio Andy,

Which file would you recommend for a brand new mower blade?

I would just need to remove the paint from the edge and true up the edge a little bit.

Trying to remove as least metal as possible.

Angle grinder with 240 grit flap disk. The paint on new mower blades is very hard to remove.

You can control the amount of hollow-grind profile by how you hold the grinder. Practice with the grinder off, just moving the wheel down the blade to see if you can keep the angle constant and using the edge of the wheel to impart any hollow-grind you like.

Use your arm position to "set" the angle and grind, then move your upper body, without changing the position of your hands and arms, to make the sweep down the length of the blade.

I'll use the grinder on a new blade and one that's badly damaged or extremely dull, then use a single-cut ******* file to put a steeper "secondary" bevel on the blade. For subsequent sharpening, just use the file.

Be sure you keep the blade balanced! I count the number of strokes on each end of the blade, starting with the dullest one, and repeat that number on the other. I rarely have to remove metal to balance the blade.

 

[Steve_P]

I've used an 80 grit flap wheel on an angle grinder for decades. Works fine. No need to use anything less than 80g, no need to use a file- it's a lawnmower blade, not a $1000 collector knife. You are going to hit sticks the first time you use it if you actually have any trees, so obsessing over this like you're constructing a Rolex, or sharpening that $1k knife, is ridiculous IMO.

You can buy a cheap blade balancer at Ace Hardware- they work well enough. After decades with the Ace balancer, I finally bought the nice "Italian" one on Amazon which is very similar to the one we had at the small engine shop I worked at in the 1980s. It is really nice, but totally unnecessary for home use.

 

[Wamsutta]

Angle grinder with 240 grit flap disk. The paint on new mower blades is very hard to remove.

You can control the amount of hollow-grind profile by how you hold the grinder. Practice with the grinder off, just moving the wheel down the blade to see if you can keep the angle constant and using the edge of the wheel to impart any hollow-grind you like.

Use your arm position to "set" the angle and grind, then move your upper body, without changing the position of your hands and arms, to make the sweep down the length of the blade.

I'll use the grinder on a new blade and one that's badly damaged or extremely dull, then use a single-cut ******* file to put a steeper "secondary" bevel on the blade. For subsequent sharpening, just use the file.

Be sure you keep the blade balanced! I count the number of strokes on each end of the blade, starting with the dullest one, and repeat that number on the other. I rarely have to remove metal to balance the blade.

I've been using a black magic marker on every pass to keep my angle in check.

I try to file across the entire width of the edge in order to maintain the factory angle.

I try to line up my eyes looking down the whole length of edge in an effort to get the file laying perfectly flat across the edge.

The edge is 3/16" in width.

It's very tempting to put a steep secondary angle on the leading edge like you mentioned, but that throws off my eyes when I'm trying to maintain the factory angle.

 

[Beerhippie]

I've been using a black magic marker on every pass to keep my angle in check.

I try to file across the entire width of the edge in order to maintain the factory angle.

I try to line up my eyes looking down the whole length of edge in an effort to get the file laying perfectly flat across the edge.

The edge is 3/16" in width.

It's very tempting to put a steep secondary angle on the leading edge like you mentioned, but that throws off my eyes when I'm trying to maintain the factory angle.

My "steep" secondary bevel is probably about what your factory bevel is. I thin the edge a bit in the primary bevel, which is slightly hollow-ground, using the flap wheel. When the edge gets too thick for me, or I damage it badly, I go back to the grinder. File for everyday sharpening.

The Sharpie trick is a time-honored method. I call it "hippie Dykem".

 

[Beerhippie]

I've used an 80 grit flap wheel on an angle grinder for decades. Works fine. No need to use anything less than 80g, no need to use a file- it's a lawnmower blade, not a $1000 collector knife. You are going to hit sticks the first time you use it if you actually have any trees, so obsessing over this like you're constructing a Rolex, or sharpening that $1k knife, is ridiculous IMO.

You can buy a cheap blade balancer at Ace Hardware- they work well enough. After decades with the Ace balancer, I finally bought the nice "Italian" one on Amazon which is very similar to the one we had at the small engine shop I worked at in the 1980s. It is really nice, but totally unnecessary for home use.

I chose to use a file for the secondary bevel as I've found this is the longest-lasting edge profile for my uses (lots of sticks and occasional rocks (thanks, kids)).

As for balance, I hang the blade from a round-shaft screwdriver. A badly out-of-balance blade is miserable to use and hard on for the mower.

 

[dscheidt]

I've always just used a bench grinder. I had to sharpen the blade on my mower three times a year when I had a gravel driveway. Lots o rock in the yard, hard on blades. Never took me more than two quick passes, and sometimes a touch on the back o one side to get the balance right.

 

[Nutria]

^ Very early on, what made the reputation of a "mechanic" (prior to their being called "machinists") was how well they could use a file.
18th Century stuff. Long prior to computers, automation, power equipment, CNC machines.

My taciturn, Swedish grandfather was a machinist at Stanley. When I was a kid, he would test me on using a file correctly (standing on a stool next to the vise). When I got it wrong, he would just walk away; when I got it right, he would grunt and walk away-- and I'd be happy. He taught me a lot.

 

[Ohio Andy]

Ohio Andy,

Which file would you recommend for a brand new mower blade?

I would just need to remove the paint from the edge and true up the edge a little bit.

Trying to remove as least metal as possible.

I would use a double cut for speed dinner I didn't need a smooth edge on a mower blade.

If it is a new board and I just wanted to rejoice the paint, single cut...