Beveling Thick Slate Factory Edge

[aockenden]

I’ve got a slab of 3 cm thick slate with a factory-cut 90 degree edge which I want to bevel to 45 degrees. I’m planning to use an angle grinder for the purpose and I’m not super fussy about making it a perfectly even bevel. In other words, I’m happy with a little touch of “waviness” in the bevel through the edge.

Question: what angle grinding blade thing would everyone recommend for this task?

 

[a twig]

A stone cutting one

 

[aockenden]

A stone cutting one

Sure but what about like those flap disc things?

 

[aockenden]

Or something like this?

Would it work cleanly on a piece of slate or would it just chip / flake the edges?

 

[aockenden]

Or something like this but hopefully for a 45 degree bevel, not a bullnose rounded edge?

 

[aockenden]

Ohhh I just realized there’s something called a grinding disc which is distinct from the cutting discs I’ve used up until this point. I think this is what I need to be able to hold the face of the disc up against the edge of the 90 degree corner.

https://www.screwfix.com/p/erbauer-masonry-grinding-discs-115mm-4-1-2-x-22-2mm-5-pack/543ph

 

[paulc]

Don't tell anyone, but I have used a 9" diamond cutting disc mounted in a table saw to cut bricks before now.
Needed to make an adaptor to match the hole in the disc to the shaft. Motor speed was (and still is) under the max limit for the disc. Was very, very dusty work even with an extractor hooked up to the table saw, but it did the job. The table saw needed a good clean afterwards.

 

[Cubist]

Ohhh I just realized there’s something called a grinding disc which is distinct from the cutting discs I’ve used up until this point. I think this is what I need to be able to hold the face of the disc up against the edge of the 90 degree corner.

https://www.screwfix.com/p/erbauer-masonry-grinding-discs-115mm-4-1-2-x-22-2mm-5-pack/543ph

That will get it done - provided the run length is fairly short, say a metre. I used one a few years back to trim up and shape some slate Plant Label Stakes for the First Lady. However, this type of blade can abrade and the diameter and cutting surface area reduces markedly with heavy use. Screwfix also have a range of Concrete grinding wheels that will perform better and are more durable I believe but the cheapest of these is more than twice the price of the one you're looking at.

 

[aockenden]

That will get it done - provided the run length is fairly short, say a metre. I used one a few years back to trim up and shape some slate Plant Label Stakes for the First Lady. However, this type of blade can abrade and the diameter and cutting surface area reduces markedly with heavy use. Screwfix also have a range of Concrete grinding wheels that will perform better and are more durable I believe but the cheapest of these is more than twice the price of the one you're looking at.

Ok thanks, I’ll give these a shot to start with and maybe upgrade if the need arises.

 

[aockenden]

Don't tell anyone, but I have used a 9" diamond cutting disc mounted in a table saw to cut bricks before now.
Needed to make an adaptor to match the hole in the disc to the shaft. Motor speed was (and still is) under the max limit for the disc. Was very, very dusty work even with an extractor hooked up to the table saw, but it did the job. The table saw needed a good clean afterwards.

Wow that sounds complicated. Good for you on mAking it work. I don’t have a table saw so I’ll stick with my angle grinder and try to muddle through.

 

[paulc]

Wow that sounds complicated. Good for you on mAking it work. I don’t have a table saw so I’ll stick with my angle grinder and try to muddle through.

You could try is making a jig to hold your angle grinder at 45°. Doesn't need to be anything complicated, and could be fabricated out of a few scraps of wood (or MDF).
Or how about this: https://www.ebay.co.uk/itm/387525797185
For a few pounds more, one with dust extraction: https://www.ebay.co.uk/itm/145919297781

 

[malcolm]

Slate is fairly soft. I would use a flap disc to sand away to get to the bevel. It'll be dusty.

Cutting is less controllable and grinding might be a little too aggressive for a thin edge.

Plain sand paper would probably be quick enough for a small length.

 

[aockenden]

Well after absolutely MANGLING a 60-quid slab of slate yesterday (trying to cut it outside in the middle of a driving gale, while my son was tenuously napping in his car seat nearby, using the cheap, slightly flexible silicon carbide cutting discs) I rallied today and had another go on a fresh slab.

I tried a new diamond masonry blade and WOW, I will never go back to the silicon carbide. No loss of disc diameter after cutting a lot of thick slate, no nasty burning chemical stink, no flexible blade wobbling inside the cutting channel, and a cleaner non-chipping cut. A comparatively heavenly experience vs. yesterday. After I got it all roughly cut, I roughly rounded / smoothed all visible edges with a grinding wheel, and then finished with a pad sander with 120 grit sandpaper. We decided against a 45 degree flat bevel and are going with the more organic smoothed, rounded look.

I’ll get some pics in the light of day tomorrow and post them.

 

[Zebra]

Diamond blades are a girl's best friend.

 

[aockenden]

Diamond blades are a girl's best friend.

I can see why!

 

[aockenden]

It fits!

 

[LadyArowana]

Diamond blades are a girl's best friend.

So many carats so little time.

 

[aockenden]

Second one done today. Diamond cutting blade did the job again like a champ. And then I switched to the grinding blade and then the sander. This one was a replacement for a prior attempt we made to fix a wooden sill board which subsequently warped and cracked. Had to slot it into the channel in the plaster where we plastered up to the wooden sill previously. Now need just need to fill in the broken chunks of plaster and then finally ready to skim the entire room.

 

[mardinor]

They look like they've always been there. Great job!

 

[aockenden]

They look like they've always been there. Great job!

Thanks, glad to hear it