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Zero Clearance Insert (ZCI) on demand.

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Project by LittleBlackDuck posted 09-15-2017 08:27 AM 20280 views 7 times favorited 15 comments Add to Favorites Watch

With all the twists and pitfalls in life, occasionally one can get lucky…
and be born beautiful like me…
and if you don’t like your face, upon your next reincarnation, ask the Obstetricians to shove you back in and pull you out with a better dial…

Now if you believe the above, stop reading woodworking articles especially by anyone resembling an Anas Platyrhynchos (duck… and more so a not too tall black one).

Now what has all that to do with ZCI…? absolutely nothing, but I bet I had you questioning my sanity regarding this post while I’m waiting for the silicon to dry on my current project… no not an implant… a glass display cabinet.

However, where I was lucky is that the step down on my table saw from the top of the table to the throat plate support was virtually 6mm (a 6mm thick MDF sanded to 320 and polished, sat flush).

Transferred the shape of the original throat plate into SketchUp and through the magic of PC, transgressed from SketchUp to Layout to Corel Draw and finally my laser… not to mention the table saw.

I have abandoned the original “splitter” that came in the shape of an anchor for the blade guard as the blade guard was impractical/useless and it reminded me of a donkey… (temporarily posing with a mag-switch shoe)

only because of the shape of anti-kickback tabs (held up by a piece of dowel in pose for the photo) that were as useless as a donkey in a cattle muster.

Replaced it with a Micro-Jig splitter (Pro version – both 1/8” and thin kerf).

While they work a treat, setup is a tad cumbersome (using their supplied jig),

which is why I now embrace my laser method.

Fortunately, with the laser, I can cut the splitter mounting holes (and the other holes) in the exact required location repeatedly on my laser (refer gallery picture #2) out of standard 6mm MDF.

After cutting the form and tidying up the thumb hole, MJ splitter holes and the screw locator holes, I hit it with 240 and 320 grit ROS and a coat of wax and buff to slicken it up and bring it to the right thickness.

I flip it over and glue a small mounting block for a “fender washer” spacer that is used as an anchor for the far end of the ZCI (gallery picture #5) against the table top throat.

While I don’t condone it (aren’t I such a nice guy for such self admission), note that in gallery picture #6, the 10° ZCI is not blessed with a “washer anchor” as the table saw fence is located over the ZCI to hold it down (was an unnecessary step for that particular requirement).

Once done I can then mount it and raise the appropriate blade, insert the splitter, test it and blaspheme as the fit is so incredibly good, the under table “dusty” cannot suck up any sawdust above the tabletop… must work on a above table dust hood.

Unfortunately the MJ splitters do not cater for 1.7mm kerfed blades.
The near ZCI in gallery picture #5 was marked as 1.7mm kerf, but due to non-conformity, was promoted to a 2.2mm ZCI after the cut jammed on the splitter.
However, once the kerf is cut I extend it manually by about 25mm towards the back, insert a 1.7mm veneer at the back of the kerf (refer gallery picture #4) and brace it with a support block,

Re-raise the blade to full height which will shape the splitter/support-block to fit. Though the 1.7mm veneer is quite fragile on the few occasions that I use that blade I take extra care in not snapping the splitter. Who says I can’t learn after snapping about 20 of them on my first day of use.

I don’t know about all you other ZCI advocates, but I had to make one of these “mushroom” plugs as after countless repetitions,

(also note the 22mm ratchet spanner that I use on the tablesaw arbor… saves the knuckle skin).

I had to prevent losing the hold down screw through the ZCI’s finger hole,

Gallery picture #6 is my current tablesaw ZCI family. The bottom left throat place is not figured redwood but the original throat plate and still has it’s use when I need to make the occasional 1 of bevel cut, without bothering to make a new dedicated plate.

I have a basic ¾” dado ZCI (gallery picture #6, bottom right), however, it’s accuracy is limited as I use a Freud “Dial a width” dado set (should also apply to all you “shimmy” devotees) as the 3/4’’ kerf is never exactly the same.

A word of advice. For all you non laser or CNC owners, when you make your first ZCI with all the layouts, put it aside as your permanent template. Ok, that was more than “a word”…

Happy ZCIing… just don’t show this to your kids as they might misread it as SKIing (Spend Kids Inheritance).

As always, if you find this article boring and/or inappropriate, I beseech you to not peruse any further.

-- If your first cut is too short... Take the second cut from the longer end... LBD





15 comments so far

View Scott Oldre's profile

Scott Oldre

1128 posts in 4926 days


#1 posted 09-15-2017 10:22 AM

Interesting read. Off to see a therapist about getting you a referral expeditiously. I use three inserts. Original, extra wide phenolic (dado) and standard kerf phenolic on my Craftsman.

-- Scott, Irmo SC

View LittleBlackDuck's profile

LittleBlackDuck

9454 posts in 2316 days


#2 posted 09-15-2017 11:22 AM

Thx for your feedback ScottieO.


... therapist about getting you a referral expeditiously….

Hope yours is cheaper than my last 10 were. The missus had to pawn her high-heeled gum boots for the deposit on my last therapy session.


... I use three inserts…

- Scott Oldre


I primarily use 3. The 3.2, 2.2 and the dado. However the dado is more for looks as there aren’t to many parts I cut with it that would let pieces fall through and the kerf seldom fits my 3/4” individual configuration… one would think 3/4” is 3/4” and not the deviance I have experienced in timber… even from the same source. Since I started making box joints on the tablesaw (as opposed to the router) my collection started to grow. I eventually imported the design into the “laserable realm” and found that it took very little effort to customise as per need. Keeps me in the workshop and out of the kitchen washing dishes..

-- If your first cut is too short... Take the second cut from the longer end... LBD

View htl's profile

htl

5628 posts in 2654 days


#3 posted 09-15-2017 11:45 AM

Thanks for the pictures but all them wordssssss!!!
Very interesting non the less.

-- An Index Of My Model making Blogs https://www.lumberjocks.com/htl/blog/130264

View Upgrayedd's profile

Upgrayedd

138 posts in 2678 days


#4 posted 09-15-2017 03:30 PM

alotta words… probably wine induced.

-- Upgrayedd - spelled thusly, with two Ds, for a double dose of this pimping.

View helluvawreck's profile

helluvawreck

32122 posts in 4362 days


#5 posted 09-15-2017 05:04 PM

Duck, this is interesting and you are a very creative fellow.

helluvawreck aka Charles
http://woodworkingexpo.wordpress.com

-- helluvawreck aka Charles, http://woodworkingexpo.wordpress.com

View htl's profile

htl

5628 posts in 2654 days


#6 posted 09-15-2017 05:08 PM

Not the Duck surely not the Ducky they like water not wine!!!
I have read when he got a little whiny but wino no way!!! :-}

-- An Index Of My Model making Blogs https://www.lumberjocks.com/htl/blog/130264

View LittleBlackDuck's profile

LittleBlackDuck

9454 posts in 2316 days


#7 posted 09-15-2017 10:58 PM


... probably wine induced.

- Upgrayedd


BINGO! My expensive therapists are vino merchants!

I’m not an alcoholic... I’m a drunk... alcoholics go to meetings!


... they like water not wine!!!

- htl


This Duck never learnt to swim… The alcohol keeps evaporating before I can get my feathers wet!

-- If your first cut is too short... Take the second cut from the longer end... LBD

View Pjonesy's profile

Pjonesy

465 posts in 2321 days


#8 posted 09-16-2017 02:09 AM

You’ve done it again Ducky. I agree with you that normal splitters (riving knives) are a bad design as we all seem to throw them out as they only get in the way.

-- Don't tell me it can't be done.

View LittleBlackDuck's profile

LittleBlackDuck

9454 posts in 2316 days


#9 posted 09-16-2017 11:54 PM

Thanks for the suspender belt (hidden support), PJ.

There are far too many woodies that have surrendered their ”splitters” for comfort and endangering their midriff. While built in riving knives should be mandatory, we with economy tablesaws, don’t share that luxury. After a 120×19 mm tattoo across my ample belly, I have summarised my views and become an acclaimed, awesome, avid, abhorrent, abject, advocate of a splitter (and any other ”A”s that may befit the topic).

If I can leave this blog with a message… incorporate a ”splitter” in your TS or spruce up you gut for an uninvited encounter.

-- If your first cut is too short... Take the second cut from the longer end... LBD

View Ocelot's profile

Ocelot

3826 posts in 4133 days


#10 posted 04-30-2021 09:50 AM

An old but useful post. If I had a laser it would be better, but… meanwhile. .

Your solution for the 1.7mn (.067 to me) blade is something I had been wondering about. I knew some people use7 1/4 inch blades on the table saw, but I didn’t know what to do about a splitter. Why veneer? Why not steel or aluminum?

-Paul

-- I intended to be a woodworker, but turned into a tool and lumber collector.

View LittleBlackDuck's profile

LittleBlackDuck

9454 posts in 2316 days


#11 posted 04-30-2021 10:37 AM



... Why veneer? Why not steel or aluminum?
- Ocelot

Primarily I hate working with metal and didn’t even consider it.
Any afterthought had me wondering how I could get 1.7mm aluminium or steel.

I made the following suggestion to some other ZCI question using metal,

however, it was only a concept for attaching. Shape and thickness was still an engineering issue above my paygrade. Also has the issue of fixed vs. non-through cuts.

Veneer out of hardwood is easier to make and shape and easier to glue.

If you are good at metalwork (steel or aluminium), you should be able to make one based on the MJ Splitter shape/principle for 1.7mm.

I just feel that stuffing around for hours justifies buying the MJ Splitter (thin) and compromising on a Diablo 2.3mm kerf.

-- If your first cut is too short... Take the second cut from the longer end... LBD

View Ocelot's profile

Ocelot

3826 posts in 4133 days


#12 posted 05-03-2021 08:10 PM

Well Duck, if the veneer breaks as easily as you say, I was feeling some concern that it might not be very effective at preventing kickback. I think it would certainly be better than nothing, but …

I’m certainly not any skilled worker in metal either, but what I would do is take the 4’ (3.2’ now) alluminum ruler that I bought to sacrifice for things like this, and cut another inch or 2 off the end and work out how to apply the flat side of it to the belt sander and measure thickness from time to time… something like that.

Or take one of those dozen’s of extra brackets that came with the window blinds years ago, that I put in a box to save for things like this, and hammer it flat (they are steel, painted white). That is, if it it’s in the ballpark thicknesswise, and put a little bump in it to make it thicker (if you know what I mean). ... and go from there. Very crude, but maybe stronger than a piece of veneer. Just what I’m thinkin’ though I’ve done nothing as of yet – and you have somethign already tested which is more than a bird (Duck) in hand… while mine haven’t even landed in the bush yet.

Either way, I would still stick it through the crack from the bottom just as you suggested.

-Paul

-- I intended to be a woodworker, but turned into a tool and lumber collector.

View LittleBlackDuck's profile

LittleBlackDuck

9454 posts in 2316 days


#13 posted 05-03-2021 11:38 PM


Or take one of those dozen s of extra brackets that came with the window blinds years ago, that I put in a box to save for things like this, and hammer it flat (they are steel, painted white)...
- Ocelot

Oh if it was that simple Oce’... Ducks don’t wear pants so you can appreciate the lack of modesty. My windows don’t have blinds and I unashamedly parade inside my house to the exposure of my neighbours. Consequently, the only way I could have those brackets is by theft… and with short legs, ducks don’t waddle a quick getaway.

Veneer sideways with the grain is quite strong and if you choose your timber carefully it could work… (eg, Ironbark,,, with thin bark… just kidding (in case some novice takes me seriously)). Height, which would contribute a lot towards it’s vulnerability (ie. too high), should not be an issue (refer to height of an MJ Splitter).
With me, my 1.7mm blade is usually used for cosmetic cuts which tend to be non through, so the 1.7mm was more an idea rather than a life preserving practice.

Nevertheless, I reckon that some carefully crafted highly polished sheet metal, maybe lined with that Slick Strip (USA sourced of course), to build up the kerf, might foot (or 304.8mm) the bill. Just need to ensure it stays vertical unless your TS tends to lean and then perpendicular.

For me, my MJ Splitters (thin kerf and standard) is what I concentrate on.

-- If your first cut is too short... Take the second cut from the longer end... LBD

View Ocelot's profile

Ocelot

3826 posts in 4133 days


#14 posted 05-04-2021 03:30 PM

I have the MJ steel splitter (thin kerf), but have never installed it because… well, you have one so you know… because it’s rather complicated to install – and on top of that I’ve been using phenolic ZCI, which MJ says should shouldn’t try to drill through with the hand drill , but just mark and then finish drilling with the DP.

So, I just use the factory splitter so far (for 15 or more years).

-- I intended to be a woodworker, but turned into a tool and lumber collector.

View LittleBlackDuck's profile

LittleBlackDuck

9454 posts in 2316 days


#15 posted 05-04-2021 11:12 PM


I have the MJ steel splitter (thin kerf), but have never installed it because… well, you have one so you know… because it s rather complicated to install…
- Ocelot

It’s only “difficult” once… and I wouldn’t say difficult but rather “involved”, though from what I remember, the intrutions are explicit and easy to follow.
Once the first ZCI is made (I only went through the installation procedure once), it should be put aside and used as a template… for routing and MJ Splitter anchor drilling… and laser cutting for me, after using the 1st. to import into SketchUp.

..... So, I just use the factory splitter so far (for 15 or more years).
- Ocelot

As long as you use any form of a splitter you are forgiven.

-- If your first cut is too short... Take the second cut from the longer end... LBD

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