# Reaming out the bore of a circular saw blade



## BigBertie (9 Feb 2017)

I'd like to buy a new circular saw blade which comes with a 5/8" bore. My saw shaft is actually 16mm, so the blade bore would be slightly too small.
Is it practical and realistic to think about reaming this out in my Woodworking workshop or should I go to a specialist? I have a floor mounted drill press, but don't have a machine reamer at present.
Any advice appreciated!


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## MattRoberts (10 Feb 2017)

I'd strongly suggest against it. Saw blades are precisely machined for balance. If the hole is even slightly off centre it can affect the balance and noise of the blade, as well as weakening it. Combine that with the load you put it under when cutting, and you could have a nasty cocktail. 

You're better off finding one with the correct bore, or a larger bore and using a reducing ring


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## curtisrider (10 Feb 2017)

Trend offer a bore enlarging service, no idea on cost though.


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## Rorschach (10 Feb 2017)

You need a good metal lathe and the knowledge to set it up properly to do a good job


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## flh801978 (10 Feb 2017)

I would be very surprised if you get a 5/8ths bore blade that it wouldnt fit on your 16mm shaft.
and indeed a few strokes with a round file will get it to go on
5/8ths is 15.875 mm so we are only talking 0.125mm.....5 thousanths of an inch
you would have to be very cack handed to get it too far out of balance if it didnt fit
my saw table is 5/8ths shaft and i routinely fit 16mm bore blades and i cant say theres much difference between them in terms of balance of quality of fit
Ian


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## woodpig (10 Feb 2017)

As Ian says it's very close. I doubt you'd get it more than a thou or two out of true by reaming it.


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## Rorschach (10 Feb 2017)

Didn't realise it was that close in size. A 16mm reamer should sort you out. If you have a drill press make a simple jig to keep it from going in cock eyed.


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## flh801978 (10 Feb 2017)

As i said i will be surprised if it doesn't go on ...you certainly don't need a reamer to ream 5 thou of a 3mm thick hole


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## heimlaga (10 Feb 2017)

I have done it successfully using a half round file and a conical piece of shafting (as reference for roundness) and some machinist's blue and a good vernier caliper to check that the hole becomes centered.


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## Racers (11 Feb 2017)

I had some done at work, they put a length of bar the existing hole size in the chuck and used it to centre the blade while its clamped then swapped for a drill of the right size. 

Pete


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## woodfarmer (11 Feb 2017)

I would try it for fit, may well be a good fit without any changes.
If not stick a bit of plank in any lathe either chucked or on a faceplate, face off the wood so it is flat at the same time leave a central stup that is a good fit in your sawblade. Locate the sawplade onto the spigot and clamp it to the wood using bits of wood and woodscrews.
now drill out the spigot using nothing bigger than 5/8 but deep enough for something tp clear the inner face of the sawblade.
If it is a metal turning lathe bore the hole to size. if not, or if you don't have a boring bar stick a round file in the hole with the lathe running. it wont take long to enlarge the hole to the size you want. Note slide the file in and out using not much pressure.


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## dickm (12 Feb 2017)

To be honest, I've done similar things to what Woodfarmer suggests, but it's potentially a bit dangerous, so be very careful doing it. Grandmothers, eggs and all that, but the file MUST have a handle and if it did catch, a file can easily snap and throw sharp bits around. 
Not saying don't do it that way, but just be aware what can happen.


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## BigBertie (16 Feb 2017)

Thanks very much for all the advice. The blade is a specialist one from the US and a 16mm bore wasn't an option unfortunately. I did try the 5/8" bore blade on the shaft and although it fitted comfortably over the thread, it wouldn't go over the arbour part itself.
I do have a drill press and was sorely tempted to have a go at polishing or reaming it out....such a small amount to remove. But this was a very expensive blade and although I was pretty confident I'd make the hole larger, it would rather defeat the object if there was any vibration etc.
So I chickened out! I managed to find an old fashioned little Saw sharpening workshop in Braintree, Essex who were happy to ream it out whilst I waited...cost me £5! So I feel a bit weedy not having tried, but relieved that my new blade now fits fine!
If this happens again, I think the suggestion of centering in a drill press with a 5/8" shaft first then reaming with a 16mm ream would be my most comfortable option...thanks again for all the responses.
BigBertie


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## SVB (16 Feb 2017)

Glad you're sorted. I was going to suggest a bit of emery cloth on a 15mm dowel would get you close enough but for a fiver for a pucker job your 'golden' as the say!

S


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