blakep82
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| posted on 2/6/09 at 09:50 AM |
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hacksaw blades for steel?
18 teeth per inch or 24 teeth?
I've found a packet of 10 cheap ones i got for £1 or something from B&Q, 2 cuts through 2" exhast tube and i've stripped half
the teeth off one already. i may as well make it easier for myself between blade changes
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hellbent345
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| posted on 2/6/09 at 09:58 AM |
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24 per inch, the finer ones are for steel and harder materials, and the larger teeth (less per inch) are for softer materials like ally
Edit:
Also, for any thin material, soft or hard, finer teeth are required to stop jamming.
[Edited on 4/6/09 by hellbent345]
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blakep82
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| posted on 2/6/09 at 09:59 AM |
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quote:
Originally posted by hellbent345
24 per inch, the finer ones are for steel and harder materials, and the larger teeth (less per inch) are for softer materials like ally
good stuff cheers 
don't know which i put on before. 18 i think. still wouldn't expect it to strip that quick though...
just having a break for now. not used to this heat in lol not sure i've ever work on the car wearing shorts before (i'm in shorts, not the
car)
[Edited on 2/6/09 by blakep82]
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hellbent345
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| posted on 2/6/09 at 10:01 AM |
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haha im in air conditioned room  but not working on the car 
[Edited on 2/6/09 by hellbent345]
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twybrow
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| posted on 2/6/09 at 10:04 AM |
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Dont buy those cheap B&Q blades. The blades are made from cheese! The worst £1 I ever spent!
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SteveWalker
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| posted on 2/6/09 at 10:04 AM |
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quote:
Originally posted by blakep82
quote:
Originally posted by hellbent345
24 per inch, the finer ones are for steel and harder materials, and the larger teeth (less per inch) are for softer materials like ally
good stuff cheers
don't know which i put on before. 18 i think. still wouldn't expect it to strip that quick though...
just having a break for now. not used to this heat in lol not sure i've ever work on the car wearing shorts before (i'm in shorts, not the
car)
[Edited on 2/6/09 by blakep82]
You also need more teeth for thin wall tube, so that enough teeth are in contact to stop the blade snagging.
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blakep82
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| posted on 2/6/09 at 10:05 AM |
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quote:
Originally posted by hellbent345
haha im in air conditioned room but not working on the car
[Edited on 2/6/09 by hellbent345]
we don't have air conditioning. not needed for the 3 warm days a year we get it was snowing only a few weeks ago
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blakep82
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| posted on 2/6/09 at 10:06 AM |
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quote:
Originally posted by twybrow
Dont buy those cheap B&Q blades. The blades are made from cheese! The worst £1 I ever spent!
too late
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balidey
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| posted on 2/6/09 at 10:21 AM |
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quote:
Originally posted by twybrow
Dont buy those cheap B&Q blades. The blades are made from cheese! The worst £1 I ever spent!
DITO.
Some things you can scrimp on, but IMHO, blades is not one of them. A decent quality blade puts a cheap chinese copy to shame.
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Flamez
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| posted on 2/6/09 at 10:35 AM |
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wouldn't the angry grinder be better for cutting exhaust tube, it did mine no bother and a nice clean cut in about 30 seconds.
my build mac1motorsports
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blakep82
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| posted on 2/6/09 at 10:47 AM |
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yeah, grinder would have done the job a lot quicker, but the sparks would have been a pain coz of the heat outside + overalls. and the heat buildup in
the tube, and quite a thick cut.
done now anyway, and the 3rd blade lasted for 4 cuts before losing any teeth. result!
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BenB
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| posted on 2/6/09 at 11:08 AM |
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I like the screwfix blades specifically made for metal- more expensive but worth it. I agree most "universal" blades are made from a
version of solder. A false economy especially considering the faff of mucking around with changing blades.
Also- found a bit of a top tip today. If you're filing ali the grooves in the file get filled with ali powder which stops the file from working.
Apparantly rubbing a chalk stick against the file fills them with the chalk which comes out as you use the file and stops this from happening.
Haven't tried it yet (got to get some chalk ) but sounds reasonable to me!!
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David Jenkins
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| posted on 2/6/09 at 11:23 AM |
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Ideally you want the coarsest blade that will give you 2 saw teeth on the work at any one time, preferably 3, so 32tpi is good for 16swg - 1/16"
- 1.6mm. If you're cutting thicker material you'll need a coarser blade, otherwise you'll be there for ever as the throat of each
saw tooth gets clogged up with swarf very early in the cut. I have 2 hacksaw frames next to my bench - one's got a 32tpi blade, the
other's got something like 15 or 18tpi. Both get used often.
As for blades - get the best you can afford, but NOT the 'all-hard' type. Those are excellent for experts, but not for part-timers like
us as they are far too easy to break! The ones you want to look for are called 'bi-metal' or similar - the teeth are cut into a strip of
super-hard steel, which is then welded onto a more flexible backing strip. Good for cutting, but far harder to break (but not impossible).
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dhutch
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| posted on 2/6/09 at 11:23 AM |
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Eclipse are pretty much industry standard for hacksaws.
- Avilable from BnQ but expesive, slightly cheaper and screwfix, cheap again on ebay for packs of 10etc.
As said, finer teeth for softer materials, middle for steel, super fine for stainless etc.
- Also, finer for thiner materials (inc thin wall tube) following the rule of a minimum of three teeth on the material at any time. (24tpi = approxx
1tooth per mm)
Daniel
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flak monkey
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| posted on 2/6/09 at 11:36 AM |
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As David Jenkins says.
Cutting some 5mm steel plate up at the weekend and using a 14tpi blade which slices through it very nicely - even in my rather hot garage!
16swg tube needs a nice fine blade, but depends on your technique. You can rip through it with a coarse blade (18tpi) as long as you dont put too much
pressure on.
David
Sera
http://www.motosera.com
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twybrow
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| posted on 2/6/09 at 11:37 AM |
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Oh yeah, Eclipse are good. They last forever too!
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MautoK
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| posted on 2/6/09 at 12:11 PM |
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Another vote for Eclipse 
He's whittling on a piece of wood. I got a feeling that when he stops whittling, something's gonna happen. (OUATITW/Cheyenne)
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britishtrident
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| posted on 2/6/09 at 02:00 PM |
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Ellipse HSS 24tpi blades --- expensive but I cut my whole chassis with 1 blade ----- to do that you will also need a decent Eclipse hacksaw
frame and a bit of experience
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jimgiblett
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| posted on 2/6/09 at 02:17 PM |
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I've tried load but keep coming back to Sandvik blades. Not cheap but last well.
- Jim
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Mark Allanson
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| posted on 2/6/09 at 09:24 PM |
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A bit of screwfix cutting oil on a bi metal blade cannot be beaten. Number of teeth is for the thickness of the material, not the hardness
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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blakep82
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| posted on 2/6/09 at 09:37 PM |
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quote:
Originally posted by Mark Allanson
Number of teeth is for the thickness of the material, not the hardness
ooh i know, but no point in using the wrng one to start with if it was going to make matters worse, ie 18 tpi, on an already weak blade was always
going to strip them off quicker.
anyway, i got all 8 cuts done, and only cost me 3 blades. i make that 30p
http://www.screwfix.com/prods/20701/Blades/Hacksaw-Blades/Eclipse-Hacksaw-Blades-24Tpi-300mm-Pack-of-10
can't really knock it, considering i've had the £1 ones hanging about for years...
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David Jenkins
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| posted on 3/6/09 at 07:48 AM |
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Can't remember the last time I bought a hacksaw blade - probably 2 or 3 years ago.
Buy good ones, look after them and use them properly and they'll last for ages.
And they still cut well, before anyone says anything!
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hellbent345
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| posted on 4/6/09 at 07:39 PM |
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quote:
Originally posted by Mark Allanson
A bit of screwfix cutting oil on a bi metal blade cannot be beaten. Number of teeth is for the thickness of the material, not the hardness
Not just for thickness of material, for hardness too. If the material is soft it should be coarser, if it is harder it should be finer. If the
material is very thin, yes, the blade should be super fine.
http://www.accessmylibrary.com/coms2/summary_0286-23882801_ITM
[Edited on 4/6/09 by hellbent345]
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