Is granite a good router table top?

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208
Location
central florida
I came across a 5 foot by 4 foot granite slab from for a counter top that is cheep enough for me to use for my new router table. I know these things are pretty darn flat but how do they fair as a work surface.

I know its tough enough. but does the work slide over it very well?
Is it too hard to mortise the router plate into and how much would the bit cost to do that? Would the bit be so expensive that its not worth it?

any input would be appreciated.
 
Steel City Tools use Granite for the machine tops so I would think it would work. BUT I would contact a Granite co and have them machine the area out for the router and such you cant use regular bits they are diamond bits and have to run in water.
 
i will second the fact on having the granite company cut out the hole, so you should get your inset top first to have the right fit.. wood should slide across it very nicely..
 
I wont third that but I'm a different breed and cut stone on a regular bases.:thumb::thumb::rofl::rofl::rofl:
If you don't have the stuff and don't have any experience messing with stone take it to a granite counter top place and have it done. Ok so I third that:thumb::rofl::rofl::rofl:
 
I have cut stone but only along an edge. I have polished it also but that isn't anything like rabbiting a square hole at a specific depth.

I wasn't thinking of getting any one else involved because of the cost. I bet having some one do the hole for me would be more than the granite. I would only be paying $75 for a 5' by 4' slab. thats why I wanted it. that and the fact I know it will be flatter than anything I build.

Chuck: I have the template that comes with the router plate I want to use. If I had a diamond bit, would it last long enough without water to make the rabbit I need?

I was thinking this http://www.toolocity.com/diamond-finger-bit-with-12-shank.aspx or maybe 2 of them because they are cheep.
 
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If I could get a 4'x5' slab of granite for 75$, I'd buy it and figure out what to do with it later.

You could always cut chunks to use for Scary Sharp Sharpening.

That's a bargain, and I agree with Paul, it wouldn't hurt to ask how much to get a hole rabbeted in it.
 
first off check it for flatness. something made for a countertop isnt "engineering" grade of stone. the polish is for appearances not for precision. Then, as said above bring it to a couple of reputable granite shops along with your insert and any other milling you need done for a quote.
imo you may be better off just buying a 3 hp shaper with a 3/4" spindle. the cutters are still reasonable and you can perform an awful lot of operations with it that a router is just simply outclassed. And you can add a router collet as well to make use of your existing bits but do not use 1/4" shank only 1/2" if you decide to go that route.
 
I'm asking the guy to check for flatness for me.

Rich: this is also my table saw extension table and I already have a very nice lift and aluminum plate with a 3+hp hitachi router attached. Going shaper would mean getting rid of those also.

But I just thought about the miter slot. I know I can cut that because I can use a skill saw for that with multiple passes to remove most of the material but then the granite may not be thick enough to support itself in that spot. With out going to the shop I thing the aluminum miter slot is 3/8 thick. Some granite is only 1" thick. that would leave 5/8. off course there would be a frame around the edge of the table but that 5/8" thick area will be very weak. Right?

any thoughts.
 
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Could you mount the granite on a piece of 4/3 in plywood for strength?


I was wondering about that too. He just sent me a picture. its hard to tell but it looks like it 1" thick. If I just made a table with a 3/4" top then I cold just place it on that but I do not know if that would keep it from cracking at the miter slot.

Depending on the answer to the questions I just sent him I will be picking it up tomorrow unless some one beats me to it.
 
Right. If you insist on the granite, then support the miter slot by epoxying on a 3/4" thick piece of granite.

Some thoughts about this. It seems to me that granite brings more negatives to this than positives. How flat and how thick is this stuff? What kind of infrastructure do you plan under this thing? The granite countertops I've seen are fully supported by a substrate. They are susceptible to fracturing under relatively slight impacts. There is no need for them to be dead flat in this application. And weight can become an issue as well.

The only thing a router table MUST be is flat and REMAIN flat. The reason is that the table top is a reference surface relative to the bit. The best use for a router table is for routing pieces that are too small to support the base of the router when routing. However, the reality is that most use the router table and router as a shaper. Therefor choose a top material that is flat and support it underneath so it remains that way.

With regard to miter slots, consider this. A round cutter like a router bit has no need to pass the material parallel to it because there is no parallel with a circle. A saw blade is a linear cutter and material has to be presented to it at one angle only. A miter slot parallel with the blade is useful, even necessary. Not true with a round cutter.

One more thought, just because there are large router tables, miter slots in router tables, and drop in router bases, doesn't mean that those are the best idea. The thinking we bring to the router and its use is too often lock step with linear cutters like saws. And that can complicate the use of the router and make things unnecessarily difficult, even unsafe, and hugely frustrating.

Just a couple of centavos from the Router Lady (retired).

For more info, come to Burning Wood at Brent's in Nevada in June. Or track down a copy of my book, Router Joinery Workshop. It was printed 10 years ago but the principles of operation don't change.
 
"For more info, come to Burning Wood at Brent's in Nevada in June. Or track down a copy of my book, Router Joinery Workshop. It was printed 10 years ago but the principles of operation don't change. "

and neither does its author:)
 
I've never built a router table, so I may be missing something, but why would you need to rabbet it? Just tell them you want a hole cut in it for a 12" square sink. :) They're professional hole cutters, after all. The can radius the edges however you want, etc (think holes for undermount sinks).

Did you see the thread on Sawmill where another guy has done exactly what you're thinking about?

http://www.sawmillcreek.org/showthread.php?84803-Router-Table-Top-Gloat!
http://www.sawmillcreek.org/showthread.php?86201-Granite-Router-Table-Finished-Pics

EDIT - I read through the first thread for you and pulled out the pertinent quote:

As far as the table top goes I'm planning on using 3/4 ply on the top of the cabinet with a hole cut 3/4" smaller than the opening in the granite and attach the 3/4" Birch strips for the plate to set on. I'll be using brass inserts with set screws under the plate to level it up and using the four corner holes in the plate to mount it down to the Birch ply. By doing it this way, if you have to change the strips out for whatever reason you don't have to remove the old adhesive from the granite. Also by using a ply sub straight I can add a border of maple to the outer edges and round the corners. That's what I'm thinking anyway. Things might change as I go.
 
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I had a somewhat similar question, but it involved the use of Corian of a size similar to your granite as a potential router table top. Carol gave me some good, similar advice as she did to you above. I now have my doubts about making a full blown router table, especially from Corian, as a bench top model may very well suit my needs. I bought her book on the recommendation of Rob Keeble and others and am waiting on delivery. Come to think of it, I bought it off Amazon on Feb 27th. Hopefully, it will arrive soon?? I plan on using her book for deciding what I will finally do for a router table.
 
Ok; Lots of good stuff here. I didn't quote it because of the long replies. thanks by the way.

I asked the seller to check the granite for flatness and he claims its very flat. I'm gonna bring my 5' straight edge and see for myself. I have a feeling the top is flatter than anything I can make. My last 3 attempts at making flat tops has not yielded the best result for me. I have no idea why I can't get things flat. it just doesn't seem to be in my skill set.

The router table is also my TS extension. I originally put it there to save space and that has worked well for me. I know many people prefer a shaper and say it cuts better but I already have the router lift and plate and router I purchased just to do this some day so I am kinda set on this course. I have to go look at it and get a name to tell everyone. its supposed to be a pretty good set up.

I am going to put the granite on a 3/4" substrate. That seems to be the right direction. I like the idea of the router plate sitting on the substrate as opposed to the granite. I may just do that. But i have found some braised diamond bits for stone on clearance and since I have been thinking of it the rabbit isn't that deep. The aluminum plate is less like 1/4" thick. that shouldn't be too hard ( I dont think. )

I am going to order your book also carol. I am going try to find a used one first but if not I'll look on amazon. It would be cool to read something from an author I kinda know on a subject I love.

Looks like I am getting it tomorrow. wish me luck so it doesn't crack in half on the way home. Its a full 1+1/4" thick by the way.
 
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