Joining 2 cabinet table saws together. Tap new holes or clamps?

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Forum topic by Holbs posted 04-09-2021 05:48 PM 693 views 0 times favorited 9 replies Add to Favorites Watch
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2379 posts in 3115 days

04-09-2021 05:48 PM

With my home security issues seemingly resolved after nearly a year, I have moved my work vehicle out of my 2 car garage wood working shop and ready to irritate folks with all kinds of goofy projects & questions :)
I did purchase a Sawstop ICS 52”. Already have a Unisaw 52”. I am trying to combine the two (Sawstop for normal rip cuts, Unisaw for dedicated dado or secondary cuts). I have the Unisaw aligned & coplaner with my 4’x8’ outfeed table (ooo….really gotta upload projects and tool reviews shortly) set to the right of my not yet aligned/coplaner Sawstop. Joining everything across the top with the associated cast iron wings. I also have a Bench Dog cast iron router table that will be attached to the Unisaw. That’s alot of cast iron :)
I will need to tap new holes in the Unisaw cast iron top to accept the 52” rails from the Sawstop. Same for the Bench Dog.
I have never tapped holes before. I assume I should go with M8’s as that is what the Sawstop is using for it’s top. Between the Sawstop right side extension and the Unisaw, I am thinking should only need metal beam clamp the two tables together instead of bolts as there should be enough support structure from the 52” rail assembly and from the table tops themselves.

Tapping cast iron for M8’s. Sounds normal to do or are there some gotcha things to worry about?

-- The Carpenter Bee is derived from the Ancient Greek word wood-cutter "xylokopos/ξυλοκὀπος"

9 replies so far

View therealSteveN's profile


7700 posts in 1660 days

#1 posted 04-09-2021 06:55 PM

Probably going to end up being your best use of space available to you, but most 2 saw shops I have seen have them facing each other, with a common outfeed table between them. Most times I have seen this one is right, and at the other end of the outfeed that saw is on the Left, leaving open table in front of both for longer pieces of work.

Your thought of dedicated Dado is usually listed as the reason for it. In my case I am considering it for R and L tilt saws, as I have one of each.

-- Think safe, be safe

View MrRon's profile


6024 posts in 4329 days

#2 posted 04-09-2021 08:28 PM

Setting the saws side by side, will allow the use of one common fence rail; end to end will need two fence rails.

View Holbs's profile


2379 posts in 3115 days

#3 posted 04-09-2021 11:41 PM

I used to have a Powermatic 66 and this Delta Unisaw face to face. Lots of pro’s to such a setup. However, the one of the con’s was that I had no rearward space to speak of. If I had a 2’ or 3’ board to dado, no space.
With the side-by-side, this allow me to have a 4’x8’ assembly table with storage under the top.
I guess it comes down with saving real estate. As I’m that One Guy who has too much in his dinky 2 car garage!
The question remains about tapping a screw hole into cast iron. I’m pretty sure it’s OK to do.

-- The Carpenter Bee is derived from the Ancient Greek word wood-cutter "xylokopos/ξυλοκὀπος"

View ibewjon's profile


2422 posts in 3879 days

#4 posted 04-10-2021 03:20 PM

Cast iron is fairly soft, easy to drill and tap. Also easy to drill out of round holes if you don’t hold the drill carefully. Use a good lube, and turn the tap slowly, in and out to clear the chips. Don’t rush. I will be drilling my shaper table to mount a power feeder when I get time.

View pintodeluxe's profile


6378 posts in 3899 days

#5 posted 04-10-2021 03:26 PM

I’m currently doing a two saw setup, but they’ll be back-to-back. A short outfeed table will connect them, which allows room for miter bars and sleds etc.

I had to drill out the cast iron on my Laguna bandsaw to mount an outfeed table. I used a self centering doweling jig and it worked fine.

Good luck with your cool idea.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View tvrgeek's profile


1870 posts in 2735 days

#6 posted 04-10-2021 03:58 PM

I would drill holes and use bolts and nuts, but that is me. Don’t know your clearance or access restrictions.

I would be careful to put both saws on the same subframe as any tilt might break the tops.

Normally, you don’t use lobe to drill cast iron. I use my Cobalt bits. I Always drill a 1/8 or so first, then side correctly. Don’t get triangular holes that way.

View Kudzupatch's profile


197 posts in 2294 days

#7 posted 04-10-2021 04:11 PM

Currently have an old Unisaw and Shaper side by side. They don’t really move so don’t need clamping. But I used a couple of c-clamps on the tables to hold them together. Just push them together and don’t over tighten them. Cast iron will break.

Cast iron is easy to drill and tap but as long as you have lip there I would clamp them together.

-- Jeff Horton * Kudzu Craft skin boats*

View Robert's profile


4557 posts in 2566 days

#8 posted 04-10-2021 08:35 PM

I just clamped mine with small C clamps.

IMO they need to be further apart or will interfere. At least that’s what my experience was. I would put the wing back on the left side of the Unisaw.

-- Everything is a prototype thats why its one of a kind!!

View Holbs's profile


2379 posts in 3115 days

#9 posted 04-17-2021 11:18 PM

Thanks guys. Tapping a couple M8’s was not shabby at all through cast iron. Did use tapping fluid just to cover all bases. Went through like butter. I did bolt other places as well, especially the Benchdog cast iron router table. That has 5 fasteners. Might even put a brace under there (to be safe).

-- The Carpenter Bee is derived from the Ancient Greek word wood-cutter "xylokopos/ξυλοκὀπος"

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