set screws in homemade zero clearance inserts

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Forum topic by WorksInTheory posted 02-05-2014 06:02 AM 2596 views 0 times favorited 15 replies Add to Favorites Watch
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156 posts in 1799 days

02-05-2014 06:02 AM

Hi – 1) don’t know if I put this in the right category, 2) don’t know the rules around starting a new question or replying to someone else’s relative topic or really old topic (is that rude even to jump in on someone’s else’s thread? don’t know).

But here’s my question – when you make your own zero-clearance insert and put set screws in, what is the dimensions of those screws? For example for Craftsman they are 1/8”. Typically people use 1/2 and route or drill to accommodate the tabs and then put in set screws.

So how long are these set screws for a 1/8” insert? I saw options for example on HD site 3/4, 3/16, etc.

Do you just drill slightly smaller and then screw them in or tap them in?

15 replies so far

View Paul Stoops's profile

Paul Stoops

352 posts in 2758 days

#1 posted 02-05-2014 05:54 PM

Your question is a little hard to answer because you don’t really specify what the thickness of your ZCI is. The ZCI’s I made for my Ridgid R4511 are 1/2” thick, so I used 1/2” long 10-24 Allen head setscrews. For wooden ZCI’s I just drilled a slightly undersize hole and screwed in the setscrews. However, for my phenolic ZCI’s I drilled and tapped the holes because the material is very hard. In general, I would think using a setscrew the same length as, or slightly less than, the thickness of the ZCI in the area where they will be mounted—some saws have ledges where the screws are which reduce the thickness in that area. Usually, the setscrew will be set slightly under the top surface of the insert, allowing you to use full thickness screws.

-- Paul, Auburn, WA

View waho6o9's profile


8516 posts in 2774 days

#2 posted 02-05-2014 06:01 PM

+1 for Paul

View mantwi's profile


312 posts in 2093 days

#3 posted 02-05-2014 06:13 PM

If I understand correctly and you insert is 1/8” thick you will be hard pressed to find a set screw that is that short and if you did I doubt there would be sufficient thickness to hold that screw in place under pressure. It sounds like you are making a zero clearance insert for a benchtop saw. I had a Ryobi BT 3000 and found the best way to level the insert with the table top was to apply tape to the ledge it sat on until it reached the desired height.

View TopamaxSurvivor's profile


18387 posts in 3873 days

#4 posted 02-05-2014 06:40 PM

If I were doing it for a very thin insert, I would wax the saw ledge very well with Johnson’s Paste wax, put a dab of epoxy in about 4 places to hold it level and put the place the insert on it level. If it doesn’t get prefect the first time, it is easy to redo.

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

View BinghamtonEd's profile


2298 posts in 2567 days

#5 posted 02-05-2014 06:42 PM

I saw a Woodsmith episode where they rub some wax on the little ridges on the saw where the set screws sit, then apply a dab of hot glue to each, then put the insert on top and push it down with a square to level it to the table. Let it sit for a minute and then you can lift it out, with the hot glue still stuck to the insert. No set screws needed. I haven’t done it yet, but plan on it, seems like it will work,

-- - The mightiest oak in the forest is just a little nut that held its ground.

View PurpLev's profile


8547 posts in 3846 days

#6 posted 02-05-2014 06:49 PM

I used blue painters tape to shim my inserts to level. no screws to play with.

but if you wanted to play with set screws, just make sure the length of screw you are getting is less than the thickness of your insert (so that you can completely sink it in), but still have enough threads to grip if you extend it 1/16 out (if you need to extend it more than that , you should probably be looking at remaking your insert).

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View CharlesA's profile


3351 posts in 1995 days

#7 posted 02-05-2014 06:51 PM

+1 on hot glue.

-- "Man is the only animal which devours his own, for I can apply no milder term to the general prey of the rich on the poor." ~Thomas Jefferson

View pintodeluxe's profile


5797 posts in 3010 days

#8 posted 02-05-2014 07:02 PM

They are pretty small maybe 1/4-3/8” diameter or so. Just buy some that are not longer than your ZCI is thick.

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

View WorksInTheory's profile


156 posts in 1799 days

#9 posted 02-05-2014 09:48 PM

mantwi – no not benchtop. Unfortunately some of the hefty saws from Craftsman, Ridgid, Grizzly have a weird 1/8” thin insert. Makes it hard to make zero clearance but can be done if you work with thicker stock and router out the edges or just the parts where it hits the tabs. You can buy Leecraft inserts but I was hoping to do it on the cheap and it seems fun to try but didn’t know about the set screw. Theoretically should get 1/8” set screw but I don’t see those and you have a great point about it not being thick enough to hold it well.

View Don W's profile

Don W

19006 posts in 2765 days

#10 posted 02-05-2014 09:53 PM

I would buy the set screws I can find, and cut them to 1/8” (or slightly less)

-- - Collecting is an investment in the past, and the future.

View WorksInTheory's profile


156 posts in 1799 days

#11 posted 02-06-2014 04:13 AM

pintodeluxe – those are mighty nice – what’s the material or did you paint them red?

View mantwi's profile


312 posts in 2093 days

#12 posted 02-06-2014 05:13 AM

I have an old Grizzly G1023 and though the insert supports are thicker than a 1/8” they wont allow the use of 3/4” plywood without altering it. As you said in your original post I had to reduce the thickness around the perimeter of the ZCI I made and then use a layer or two of tape to bring it level with the tabletop. I’d forgotten that but without going out to the shop would estimate the thickness to be about 3/8” where it sets on the supports. While this is thick enough for set screws I didn’t have any at the time and the tape works fine. Why complicate the matter unnecessarily, once you dial in set screws it’s not like there’s a need for constant adjustment so they offer no advantage over using tape or as BinghamtonEd suggested a dab of hot glue on a waxed surface. That’s an excellent idea and I will use it on my next ZCI. God bless.
PS be sure to put a # 4 or #6 finish nail on the back end of your insert to contact the underside of the table and keep it from being lifted out of the slot by the rotating blade. I hate it when that happens, too much excitement for an old guy.

View Woodknack's profile


12430 posts in 2577 days

#13 posted 02-06-2014 07:59 AM

I tried the hot glue and went back to set screws. I had 2 problems: Sometimes the glue would rebound after pushing the insert into place and if you don’t get the insert perfect the first time you have to peel off the glue and start over. Second, sometimes after a few weeks or months the hot glue would fall off the insert (mdf). Drilling a hole and twisting in a set screw was much easier.

-- Rick M,

View WorksInTheory's profile


156 posts in 1799 days

#14 posted 02-06-2014 07:26 PM

mantwi – 2 questions for you.

On not needing to adj set screws again – isn’t there some change caused by temp/humidity esp if you use a plywood insert plate, but I assume even using a cutting board, etc those can expand and contract?

next – you mentioned a G1023 – I am looking at 2 of those on CL and was wondering how you like it. They look nice and I would have to get 220 (which from my other post, still pondering – got an electrician coming to look tomorrow). Also it doesn’t come w/ riving knife looks like – did you get an aftermarket?

View Don W's profile

Don W

19006 posts in 2765 days

#15 posted 02-06-2014 09:25 PM

I love my G1023. Mine doesn’t have a riving knife.

-- - Collecting is an investment in the past, and the future.

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