Bandsaw blade tension?

I've recently acquired a Wadkin C6 bandsaw. Is there a rule of thumb for tensioning a bandsaw blade? This is giving me some problems; I tend to err on the soft side but don't want to winch it up to hard and start snapping blades. Length of blade is 177 inches.
At present I'm using the blade which came with the machine which is three parts knackered.
Whilst writing. The two cast iron wheels (23" dia) have rubber, perhaps polyurethane, tyres which are showing signs of wear. The tyres seem to be available but at 50 something quid per. This seems exorbitant to me. Any ideas for a DIY solution? I was thinking of removing the existing and glueing strip material onto the wheels. I don't know if the tyres should have a slightly domed centre, existing certainly have not.
Thanks, Nick.
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It's too tight when the length becomes 178 inches
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In message

Mine is a Bursgreen 20" BZB.
The wheels should be crowned.
Tension adjustment is via a handwheel and scale. The scale needs to be set for the width of blade you are using.
I am scrapping a metal cutting bandsaw which (I think) has 20" wheels in fair order. I have no idea if they would fit the Wadkin and may be too narrow anyway. Wheels can be serviced but I have no experience of time/cost.
regards
--
Tim Lamb

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Nice. My bandsaw is a little one (Axminster 350, 14" wheels) - it's one of those machines where you don't realise how useful they are until you have one, then you wish you had a bigger one. There's no substitute for wheel diameter: 18" is where the good ones start, 23" should be excellent.
Best accessory for a bandsaw is a big rack of blades.
Second best accessory is a copy of Mark Duginske's "Bandsaw Handbook". This tells you which blades you need on your rack. It also tells you how to tune and tension the blade. <(Amazon.com product link shortened)> You need a local bandsaw blade shop - most big cities, else mail order. This means rolls of blade and a welding machine - Duginske explains tooth shapes and pitches. Buy several and swap them per job - it's worth it I guess you're going to be resawing at some point. This is time for a real resaw blade because (I'm jealous) you have the machine to tension it. 3/4" or 1" wide and maybe 3tpi.
Wadkin manual is here: http://www.wadkin.com/uploads/files/Wadkin%20C5%20C6%20C7%20C8%20C9%20Bandsaw%20Manual%20&%20Parts%20List.pdf
Tuning is important (vital), but a good frame like a Wadkin should need this once per move/installation and no more. Weaker frames need upgrade springs and careful tensioning - too little is too little tension, but too much disturbs the tracking. A two foot wheel could be either flat wheels or crowned - go with whatever the original design was.
Blade guides on a Wadkin are bearings and pretty good - nice for wide resaw blades. For a narrow blade for scroll work, take the bearings off and fit some Cool Blocks instead (bearings will destroy a narrow blade if they slip). Or else chunks of hard maple.
Tensioning is less critical the bigger machine you have. On a two- footer, just wind the bastard tight until it screams and it will still take it. Mine bends like a Liberal back bencher under a three line whip, so excess tensiuon screws with tracking and tuning. It's best (if you're obsessive) to tension to a given strain (length elongation) rather than a specific stress (tensile force per area). This is mostly because it's easy (but pointless) to measure tension, OK to measure strain, but hard to measure stress. You can rig up a "clamps and measured gap" widget that's as good as anything expensive with a dial gauge. Otherwise just tighten to a mid-piano note for tension and luxuriate that your big bandsaw makes this a non-critical adjustment.
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Go to www.ukworkshop.co.uk and use the forums there to get all the information you will need on bandsaws. Find Steve Maskery in those Forums and also on www.workshopessentials.com - get his DVD's Workshop Essntials 4 and 5 for bandsaw use and setting up. Absolutely excellent. There is also a very good blade supplier whose name I can't now remember on that site who does blades by post no more expensive than from a local supplier.
You really are a lucky chappie to get such a bandsaw and yet know nothing about them. Andy is right about the tuning note - I reckon A below middle C. But do find out how to set the whole machine up, or you will do more damage to it. And yes it will cost you to get the wheels re-tyred, and bodging it will just waste the machine.
Rob
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robgraham wrote:

This is blade supplier that Rob refers to http://www.tuffsaws.co.uk / You will be hard pushed to find a better blade or better service than Tuff. Bob
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Many thanks to all for all the good and interesting info. I have known Ian John of Tuff Saws (previously Dragon Saws) for some years. As Bob says, he is excellent. Thanks again,
Nick.
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