Shopsmith 1 1/4" arbor - 30mm saw blade bore

h-bomb · Post by **h-bomb** » Wed Jun 01, 2011 8:25 am

Here in the UK all blades are metric.

10" saw blade is 254mm, therefore 250mm blade.

5/8" arbor is 15.875mm, so a 16mm bore is fine.

But they do not seem to do 250mm blade with 16mm bore.

1 1/4" arbor is 31.75mm, the bores are 30mm.

I was wondering how easy it would be to mill a 1 1/4" boss to 30mm.

Concerned about getting saw blade onto arbor because of thread, balance of arbor and if the arbor has any surface hardening.

Any help would be appreciated.

peterm · Post by **peterm** » Wed Jun 01, 2011 11:01 am

I understand your message to be saying you can get 250mm blades but they have 30mm center holes.

If you reduced the arbor, you would also be reducing the thread, so the nut would be a very loose fit..........not a good thing for a saw blade spinning at 3500rpm.

I would think it would be easier to get a saw blade hole opened out to fit a standard SS arbor. The blade can be centered in a 4 jaw chuck by a machinist and bored to fit quickly, which should not cost too much.

h-bomb · Post by **h-bomb** » Wed Jun 01, 2011 1:18 pm

prmindartmouth wrote:I understand your message to be saying you can get 250mm blades but they have 30mm center holes. Yes

If you reduced the arbor, you would also be reducing the thread, so the nut would be a very loose fit..........not a good thing for a saw blade spinning at 3500rpm. I thought that you might just be able to reduce the boss where the saw blade sits and not touch the screw thread.

I would think it would be easier to get a saw blade hole opened out to fit a standard SS arbor. The blade can be centered in a 4 jaw chuck by a machinist and bored to fit quickly, which should not cost too much.

Thanks for your reply it looks like cutting the blade looks the best bet.

h-bomb · Post by **h-bomb** » Wed Jun 01, 2011 1:49 pm

prmindartmouth wrote:I understand your message to be saying you can get 250mm blades but they have 30mm center holes. Yes

If you reduced the arbor, you would also be reducing the thread, so the nut would be a very loose fit..........not a good thing for a saw blade spinning at 3500rpm. I thought that you might just be able to reduce the boss where the saw blade sits and not touch the screw thread.

I would think it would be easier to get a saw blade hole opened out to fit a standard SS arbor. The blade can be centered in a 4 jaw chuck by a machinist and bored to fit quickly, which should not cost too much.

Thanks for your reply it looks like cutting the blade looks the best bet.

Sorry repeated by accident.

peterm · Post by **peterm** » Wed Jun 01, 2011 1:54 pm

Take a look at this typical saw arbor:
[ATTACH]13222[/ATTACH]
The shoulder is 31.75mm (1.25") o.d. and the thread is 31.57mm (1.243") o.d. You would have to take the tops off the thread to get the blade on. Sorry.

h-bomb · Post by **h-bomb** » Thu Jun 02, 2011 4:32 am

Thanks Peter, away from workshop so couldn't see arbor.

michaeltoc · Post by **michaeltoc** » Sat Jun 04, 2011 6:37 am

A good saw sharpening shop should be able to easily bore out a blade to 1-1/4".

Have you considered purchasing a blade from a US supplier? Perhaps the extra shipping charge may offset the cost to re-bore a blade?

robinson46176 · Post by **robinson46176** » Sat Jun 04, 2011 9:32 am

For such a small change of diameter most sharpening shops would "ream" the hole rather than boring it. If that were my circumstance I would just buy a reamer the proper size and type and do my own and have the reamer to use again the next time. Now before anyone panics about losing accuracy, I am not talking about some crude old pipe reamer or a steeply tapered reamer. Proper reaming is a highly accurate and controllable operation. In many applications a hole is drilled then reamed for further accuracy. It will require a bit of research to find the proper reamer for the job but owning it will give you a lot of freedom in buying blades in the future.

Sometimes the "pro's" are not too accurate.

I have an old buzz-saw blade around 30" that has the center hole about 1/4" off center.

Somebody must have had a bottle hidden in their toolbox.

pennview · Post by **pennview** » Sat Jun 04, 2011 10:16 am

Why not contact these folks -- http://www.craft-supplies.co.uk/shopsmith/ -- who sell and service Shopsmith equipment in the UK. They must have an easy solution to the issue of the Shopsmith's imperial-sized spindle and metric-sized holes in saw blades in the UK.

JPG · Post by **JPG** » Sat Jun 04, 2011 12:19 pm

pennview wrote:Why not contact these folks -- http://www.craft-supplies.co.uk/shopsmith/ -- who sell and service Shopsmith equipment in the UK. They must have an easy solution to the issue of the Shopsmith's imperial-sized spindle and metric-sized holes in saw blades in the UK.

Of course they do. It's called Shopsmith blades!:rolleyes: