Variable pitch saw

[gbravo]

I just bought an Milwaukee portable band saw, when I go to buy saw blade replacement, I discover the offer of variable pitch saw. What are the advantages and disadvantages of this kind of saw pitch?

What are the reccommended pitch for mild steel bar stock cut, within 0.5 to 3 inches?,

 

[MachineTom]

A variable pitch saw blade is designed to cut a wide range of material thickness. Like any comprimise it is not the best at all things, but is good enough at them that you don't have to change blades for sake of the pitch alone.

For best results a blade should have 3 teeth minimum cutting at all times, if not it is very easy to catch a tooth, which will break off, now you have no tooth to cut with, next time around, the gap now grabs another tooth and now 2 are missing. At this point you need a new blade, unless you use that blade only on thick material.

Say a 8-12 pitch blade, will cut from .2-.5" thick material,you can cut thicker material but you give up speed, over a coarser pitch, thinner than .2 is not recomended as the problem of catching a tooth come in.

Look some time while cutting a piece of 3/8 with say a 10-14 blade, the chips are continuous stream, now cut a piece of 3" material, the chips have a stream then slow and then another stream then slow. This is because the gullets of the teeth are filled with chips, and no cutting can take place, then those teeth have cleared the work, the next set of teeth can really cut, until then fill up, and it is repeated until the cut is completed. For 3" material a 3/4 pitch is the recomended size. You should use the coarist blade you have with a pitch of at least 3 teeth for the thickness.

 

[Tin Falcon]

gb : I think tom covered it well. but will throw out my $0.02 as well. I can attest to the fact that thin hard material will strip the teeth right off a blade. I worked years ago in a military shop New Jersey air guard. I went into work one day and there was what appeared to be metal chips on the band saw. No big deal closer inspection it was not chips at all but saw teeth. and this was no small bad saw it was a do-all about 8 foot high the blades IIRC were somewhere around 12 foot long. And hardly a tooth left on it. I can only surmise that someone was cutting a thin hard piece of metal and was too lazy to put the proper blade on. All folks in the shop were trained and the saw was key operated. only trained personnel had keys.

Too coarse a blade an you lose teeth to fine a blade and there is not enough chip clearance and the blade chokes. so always a trade off.
Tin

 

[Mosey]

This really belongs on the Oops Blunders and Boo Boos, but I coudn't resist. Laugh with me.
I have a Delta band saw for many years, and use it often. Last week I went to cut some .040 Stainless Sheet, and it just got hot as hell and woudn't cut at all. The kerf actually started to glow with the heat. Wow, that stuff must be very hard?
Well I looked closely at the blade, which was covered in fine metal flakes and I saw what was making it hard to cut... I had the blade inside out, so I had been attempting to cut with the back of the teeth!!
I reversed the blade to the proper direction, and voila.. it cut like a dream! (all of the teeth are still OK, luckily).
Pretty dumb, huh?

 

[steamer]

As long as you have your eyes, fingers and toes....its no big thing!

Metal parts are replaceable.....oh and I've seen worse...and done worse still!

;D
Dave

 

[Ken I]

First time I got to weld a bandsaw blade - as an apprentice - satisfied I had done it correctly I took it to the foreman for inspection - as instructed - he turned around to grab his reading glasses (whilst surrepticiously turning the blade inside out) - he then inspected the weld and said "Good, well done but you silly b....r you've welded it back to front"

Being none the wiser I broke the weld (as instructed) and did it again - being very carefull that the teeth faced the right way.

The foreman pulled the same trick again - I did it again - the third time I realised I was being had and figured it out and filipped the blade back.

Needless to say I've subsequently had my share of fun with apprentices.

 

[Tin Falcon]

all of the teeth are still OK, luckily).

I would check the blade carefully make sure you did not remove all or most of the set on the teeth.
Tin