Please don’t run sawblades backwards

[Tom Walz]

Please don’t run sawblades backwards

You can run a saw blade backwards and it cuts pretty well. However it is not at all a good idea.

The two big reasons not to do this is that saw tips are much more likely to come off if the saw blade is run backwards and that the whole saw blade is much more likely to come apart if it is run backwards.

Thank you,
Tom Walz

[Mike Henderson]

I never heard of anyone intentionally running a saw blade backwards - only by mistake. Are you receiving reports of people running saw blades backwards for some reason or other? If so, why would someone intentionally run a saw blade backwards?

Mike

[scott vroom]

I'm trying to imagine why anyone would intentionally set up a saw blade backwards.



Please don’t run sawblades backwards

You can run a saw blade backwards and it cuts pretty well. However it is not at all a good idea.

The two big reasons not to do this is that saw tips are much more likely to come off if the saw blade is run backwards and that the whole saw blade is much more likely to come apart if it is run backwards.

Thank you,
Tom Walz

[Steve Kohn]

I've reversed the blade on purpose when cutting aluminum siding. The blade doesn't chatch the thin alumimum this way.

Note, I've only done this on circular saws using steel blades (not carbide tipped).

[ed vitanovec]

I have heard of reversing the blade to cut thin sheetmetal roofing, I personally have never tried it.

[Tom Walz]

There seems to be a growing trend in deliberately running saw blades backwards to cut sheet metal or sheet fiberglass.

Last week I received an email asking me whether it was a good idea to do this all the time or just occasionally.

I know something about how saw blades are made and, in my opinion, it is pretty hard to find a really bad saw blade anymore. However they are all designed to be run in a particular direction. Running them backwards defeats much of the engineering design.

My saw blades, as with most of my competitors, are designed and built to be much safer than is necessary. There is an old adage in safety engineering. Design it to be safe then double that. Then add one more. However misusing the product defeats much of the hard work that I and others have put in.


Running a saw blade backwards is like driving drunk, leaning on the barrel of a shotgun, holding fireworks in your fingers and similar. You can maybe do it and get by with it but it significantly increases your level of danger.


Tom

[Ken Fitzgerald]

I personally was advised and have reversed the blade in my circular saw to cut aluminum roofing. It works well. I wasn't, however, using a saw blade with carbide tips.


It makes sense that carbide tips would be more prone to coming off if the blade is reversed. No support at all under those conditions.


Thanks for the warning Tom!

[Rick Potter]

Put a dado set on backwards once, but it sure wasn't on purpose. Made a nice burn mark though.

Rick Potter

[Larry Browning]

I wasn't going to admit this to anyone, but I guess I will. I have been building a large round dining table that is made up of 12 pie shaped segments of plywood. I cut slots in the edge for splines using a brand new slot cutting router bit. Since I had never used one before, I was not suspicious of all the smoke and burning it produced. I just said to myself "These Slot cutters don't work very well". 12 pieces means 24 edges. I cut 23 before I discovered the cutter blade was mounted backwards. That last cut was like a hot knife through butter!:eek:

[Ken Fitzgerald]

Larry.....I suspect you are not the first person to have done that.....

[Larry Browning]

Larry.....I suspect you are not the first person to have done that.....

It sure made me feel stupid!

[Gregory King]

Ruuning them backwards for cutting vinyl siding. Usually the old non-carbide plywood blades, we do it all the time. But never on my good blades. Greg

[Ken Fitzgerald]

It sure made me feel stupid!

Whenever I do something like that....I look at it as insurance. It insures my ego won't get too big! LOL!

[Marvin Hasenak]

I have used a Skilsaw with the blade backwards to cut roofing tin for almost 50 years. It was the way I was taught by my grandpa, it works, roofed quite a few barns and sheds with it. Only thing that made me quit, is my son now does that for me.

[Andrew Hughes]

When I was a roofing foreman.Many of the worker did not know the direction for diamond saw blades we used for cutting tile.By the end of the day the saw whould start hopping.Last much longer if they would just look for the little arrow.
sure glad I am not doing that anymore okay my serenity is coming back now.
Even the cheapo diamond blades are designd to cut one direction.

[David Christopher]

a backwards blade works well for vinyl siding

[Mike Henderson]

There seems to be a growing trend in deliberately running saw blades backwards to cut sheet metal or sheet fiberglass.

Last week I received an email asking me whether it was a good idea to do this all the time or just occasionally.

I know something about how saw blades are made and, in my opinion, it is pretty hard to find a really bad saw blade anymore. However they are all designed to be run in a particular direction. Running them backwards defeats much of the engineering design.

My saw blades, as with most of my competitors, are designed and built to be much safer than is necessary. There is an old adage in safety engineering. Design it to be safe then double that. Then add one more. However misusing the product defeats much of the hard work that I and others have put in.


Running a saw blade backwards is like driving drunk, leaning on the barrel of a shotgun, holding fireworks in your fingers and similar. You can maybe do it and get by with it but it significantly increases your level of danger.


Tom

Sounds like an opportunity for you. Design a blade specifically for cutting thin metal, vinyl, or fiberglass. But maybe there's already blades to do that. I don't cut that kind of material so I never looked into it.

Mike

[Myk Rian]

I'm trying to imagine why anyone would intentionally set up a saw blade backwards.
Cutting vinyl siding with a miter saw.

[David G Baker]

I have used skill saws with the blade on backward to cut vinyl, aluminum and thin steel siding. It works best if the siding is well supported underneath. I use 1 1/2" rigid blue foam board for the support. I have seen the pros score the siding with a box blade and then snap it when cutting the material length way. I would never use a carbide tipped blade on metal. The fiber blades made for cutting metal works on cutting heavy industrial grade fiberglass sheeting. Hearing protection is advised when cutting steel siding.

[Bob Turkovich]

I recall reading that you should use a backward blade to cut polycarbonate sheet. I made some custom router plates from polycarbonate a few years ago but opted to cut them with a bandsaw instead.

I just googled "how to cut polycarbonate" and there are over 7,900,000 entries. The very first one recommends using a circular saw with the blade set backwards. :eek:

Looks like you've got you work cut out for you, Tom (No pun intended...):p

[Kevin Bourque]

As long as were on the subject of improper tool usage( except when cutting vinyl or aluminum siding)...

About 10 years ago a customer of mine was tiling a section of floor in his new basement bathroom.
There was a small area where the concrete floor was a little rough so he took one of my best bench chisels out of my toolbox and used it to level the floor.
When I showed up for work on Monday the chisel was lying on the floor and was completely destroyed beyond repair. He never said a word about it either!!!

I added $100 to his bill.

[Mark Ashmeade]

There's some comedy gold in this thread!

[Myk Rian]

As long as were on the subject of improper tool usage( except when cutting vinyl or aluminum siding)....
Nothing like hijacking a thread.

[Peter Quinn]

As long as were on the subject of improper tool usage( except when cutting vinyl or aluminum siding)...

About 10 years ago a customer of mine was tiling a section of floor in his new basement bathroom.
There was a small area where the concrete floor was a little rough so he took one of my best bench chisels out of my toolbox and used it to level the floor.
When I showed up for work on Monday the chisel was lying on the floor and was completely destroyed beyond repair. He never said a word about it either!!!

I added $100 to his bill.

Perhaps he used the chisel backwards?

[scott spencer]

I believe the practice started back before carbide tipped blades were popular, and got passed on as one of the "old timer's tricks". A steel blade turned backwards has the effect of a heavily negative hook angle, and was useful for cutting siding with very little splintering. Doing the same thing with a carbide tipped blade leaves the carbide tips with nearly no support, and is unwise under any circumstances.

[Edward Dyas]

What if you have a blade made to run both directions?246745