Lifetime of saw blades?

[Skywave]

It's rare for me to generate a post in this section, but I am really puzzled about a certain type of saw blade: so help / advice is requested, please.

The title is a summary: a full explanation follows.

Amongst my most used power tools is what I know as a reciprocating saw: I don't know if this is what everybody else calls one of these, so to make myself perfectly clear, I'll explain further. It could be regarded as a electrically-powered key-hole saw. There is an approximately tubular-shaped body - which is some designs is angled so as to form a handle at one end - and in-line with the axis of that tube is where a saw blade is attached to an internal reciprocating motion, driven by a motor. The motion of the blade is back and forth. The blade is attached to the saw's reciprocating arm at only one end of that arm.
Phew! Having said all that, I'm sure you knew what I am talking about in the first place: just wanted to be sure.

O.K. preamble over - down to the 'nitty-gritty'. You can buy blades in various lengths and various grades, depending on the type of material you wish to cut. The ones I usually buy are referred to as dual-purpose: suitable for metal and wood: Bosch is one of the more common makes. But I have an on-going problem with these types of blades, irrespective of manufacturer. And that is that they seem to have a very short life before they go significantly blunt. Now apart from the fact that they are not cheap, I find that even if I limit the use of one to cutting softwood / pine / PSE only, they don't last very long, despite my various attempts to modify my cutting technique to optimise the life of the blade. Now I also own a collection of conventional hand-saws: some of these have been around for many years: they still cut the same type of wood with ease - although a good deal more muscle is required - well, for me, anyway. What I don't understand is why these reciprocating saw blades have such a short life. I would have thought that being saw blades, they would have been made from an appropriate tool steel, hardened and then tempered to give them the necessary - and expected - long life. But this doesn't seem to be the case.

So, what, exactly, am I missing here, failing to appreciate or am simply doing wrong?
Helpful comments would be much appreciated.

Al.

[Mark R]

Al
I do not think it is you, I think it is to do with the speed of the reciprocating saw and the heat generated in the blade due to the cutting action coupled with said speed.
The blade will get appreciably hotter than a hand saw, much like a chain saw which need sharpening at regular intervals.
The reciprocating saw I have suffers the same problem.

cheers Mark

[60 oldjohn]

Can you be sure you are buying Manufactures Original blades? I would expect the one's that came with the saw would have lasted longer than the counterfeit blades that flood the markets and shops today with top name Bosh, De walt, etc. It may be worth sending a sample (with packaging) to the manufacturer who is supposed to have made them. If I am right why would a trader sell them dirt cheap and raise susspicion? Of course some one may know different, possibly high resin content and knots may blunt tools.
John.

[pwdrive]

Hi Al, sorry to say I don't rate that type of saw much, I have used therm in the past, what depth of timber are you cutting?
I have an electric crosscut saw (compound) running on it's original blade, it is effortless.
For sheet material I use a jigsaw or hand held circular saw on a guide rail.
For most jobs I use a hand saw, the best hand saw around is the Bacho 244 which is the one most site chippies use, you can not resharpen these succsesfully though, if they go dull just buy another, I used to get through one every fortnight when working on site, same for wood chisles...time was money. The 244 will cut through 4"x4" or even 6"x6" with ease if the timber is resonably dry and not under tension/compression. The 244 will go through PSE or sawn pine very easily an accurately.
Overheating is the death of saw blades initially caused by the blade losing it's edge coupled with too fast feed speed if feeding the timber in, or pushing the saw to fast if timber is stationary, it's down to the sawdust holding capacity of the gullet and the effective speed of rotation.
For general rough cuts you can use a chainsaw, sharpen little and often, if the cutters have worn through the chromium layer then it will have to be reground otherwise you are wasting your time.

General info: The saw does the work not you, saws can be very dangerous if not used correctly.

Lawrence. (Edit) Forgot to say the 244 used to be stocked at B&Q, failing that any decent builders merchants should have them.

[Joe]

Thanks for the tip, Lawrence. ScrewFix have them at nine quid.

- Joe

[Skywave]

Thanks for your replies.
Here is the type of blade I am referring to:

http://www.toolstop.co.uk/bosch-s522ef-f...tAodLn4Auw

Al.

[pwdrive]

Thanks for the tip, Lawrence. ScrewFix have them at nine quid.

- Joe

HI Joe, yes, the 244 is a good saw for the money, the blade is reasonably stiff, crap saws usually have a "flimsy" blade that don't "sound" right.
I think the 244 series is available with different lengths, the one I always use is the 22" model.....watch yer thumb when starting a cut. The 90 & 45 degree handle angles are pretty accurate for general jobing for up to a 6" run of cut
Eventually when they loose their edge you can still use them for cutting thermalite or durablock if you have any such work on or pruning in the garden.

Lawrence.

[pwdrive]

Hi again Al, I see now...that looks like a metal cutting blade, I'm not an expert on metal cutting blades.But if the one shown is dual purpose then maybe it is but dual purpose blades always seem to be a bit of a compromise, for wood a decent swage is required unless doing ultra fine work.

As a general observation, the average hand held jigsaw has small blades so folk would tend to view them as "better go easy with this" that other saw looks bigger so "big boys toys... better give it some"

I still don't like them, having said that they were ok for cutting underground UPVC pipes etc.

As has been said also there is an awfull lot of fake crap blades around even from "reputable" dealers.

Lawrence.

[Joe]

I got my jig saw way back in '85 and have only had to buy some new wood-cutting blades this year.

I've never had any joy cutting metal with it though. I once tried to do some mild steel which was only about 1/16" thick and after 1/8" the teeth had vanished.

I've seen reciprocating saws called "Demolition Saws" which seems to imply that they are only fit for very rough work.

I've never used one but last year I was helping my neighbour with some tree pruning and I was getting through thicker branches with greater speed and apparent ease with my bow-saw than she was with a reciprocating one.

- Joe

[pwdrive]

Picture of my trusty compound mitre/crosscut saw, it's a Makita, I've had it for years on that blade, It cost me almost a grand when I bought it, I got it for site work, it paid for itself in about a month and I never looked back, great for external mitres when banging in skirting boards for a living (scribe internal angles) You can do tennons on it too. It's had a hard life and certainly worked for its living, it's still accurate.
I have an aluminium cutting blade for it also which I used to cut the aluminium to build the aluminium parts of our conservatory, better than any hacksaw.

Joe, those bow saws are really good....and sharp!

Lawrence.