Diamond cutting discs for circular saws?

[michael412]

Anyone who knows anything about this subject will realise from the title that I'm not a professional. I've been cutting thick concrete slabs with a 115mm diamond cutter on an angle grinder, cutting in from each side as deep as it can go (i.e. not very) and then using a mallet and cold chisel to knock off the cut section and tidy up the rough centre bit as far as I can. Not a great way of working, and after I wore out the cutting disc I discovered that as a non-segmented disc it's only suitable for wet cutting anyway (I was cutting dry).
My angle grinder is too small for this job. But apart from the size it also has no control of angle, whereas I now need to cut at a precise angle to the surface of the concrete slab. Clearly the job for a circular saw I thought - they take larger discs and they all come with precise angle controls. So I start researching circular saws and blades. 235mm / 9" seems a good size - a lot bigger than my angle grinder and plenty of blades of this diameter available for all sorts of materials. But here's the rub - whereas all the circular saws of this diameter appear to have 30mm spindles, all the cutting discs of this diameter seem to have 22.23mm bores.
And the reason (as all you experienced guys will know) is that these cutting discs are targeted at angle grinders rather than circular saws - angle grinders of this size use 22.23mm spindles.
If it were the other way around (30mm bore on a 22.23mm spindle) no doubt I could get an adapter to fit, but 22.23mm bore on a 30mm spindle simply isn't going to work (and there's no way I'm attempting to bore out a disc to 30mm - that's way beyond my capability).
So, does anyone know of any manufacturer who supplies slotted or turbo diamond discs somewhere around 235mm / 9" diameter with a 30mm bore? Or is there a good reason why a circular saw should never be fitted with a concrete cutting disc (maybe they lack sufficient torque for concrete)?

Regards,
Michael

[sammy.se]

Hi, I know this isn't the answer you are looking for, but I think your best course of action is to buy a larger angle grinder such as this one: https://www.machinemart.co.uk/p/clarke- ... with-open/ instead of buying blades for a circular saw.

I would personally cut some timber at the angle needed along it's length, and then clamp that to the concrete slab, and use that as a guide for your larger angle grinder.

[michael412]

Thanks for the suggestion Sammy. How well that would work will depend upon the diameter of the boss holding the disc in place. My 115mm grinder has a 45mm boss. If a 230mm angle grinder has the same sized boss, that leaves just over 90mm of the outer part of the disc available to slide along a guide. For a guide to be able to accurately control the angle at which the disc enters the concrete it's going to need to be at least half that length - say 45mm. That means I get a cut of at most 45mm depth. It just so happens that the concrete slabs I'm cutting are 90mm thick, so a bit under 45mm (the angle of entry will effectively reduce the cut depth relative to the surface) will get me almost all the way through if I cut both sides towards each other. I'd need to get the position of the lines on each side of the slab spot on - easy if you're doing a perpendicular cut but a lot more challenging at any other angle.

I'll definitely keep that up my sleeve as a solution if I can't get a disc for a circular saw.
Here's a thought - I could maybe rig up an angled fence system for the angle grinder - that would give me a lot more depth than your suggestion (although at the cost of a lot more work).
A saw is definitely my preferred solution - I could definitely make use of a bigger circular saw than my current one, but I don't make enough use of my angle grinder to justify forking out for a new one.

[Nos]

Looked into this a while back, I could get a blade to fit, but and its a big but, check your rotation speed of the saw, and the max speed of the blade, my saw runs at 5000 rpm, all the blades that would have fitted their max speed was 2500/2700 rpm, so a no brainer, for safety reason's. The correct tool for the right job. Nos

[michael412]

Thanks Nos - very good tip.