Installing zero-clearance throat plate

[Sue Wise]

Hi Friends,
What is the best way to install a zero-clearance throat plate when blade cannot be lowered enough? I have a Delta contractor's saw with a standard carbide-tipped 10" blade. Will I need to buy a smaller blade to use to install the throat plate?

[Tyler Howell]

Welcome to SMC.
Great bunch of folks here.

Never had that problem Sue:confused:
How about a smaller diameter blade from your Csaw or a dado chipper:confused:
Load it up with some scrap then raise the blade till it punches through the ZCI.

[Jim Becker]

Susan, three methods come to mind:

1) Clamp the new insert directly over the OEM unit and raise your standard blade.

2) Use the outer blade from a dado set as Tyler suggests as it's smaller in diameter and will "fit" under the new insert

3) Route a channel in the bottom of the new insert to allow it to sit in the saw with the blade fully down

I actually have used all three methods, but typically use number two at this point for simplicity.

[Tom Pritchard]

Hi Friends,
What is the best way to install a zero-clearance throat plate when blade cannot be lowered enough? I have a Delta contractor's saw with a standard carbide-tipped 10" blade. Will I need to buy a smaller blade to use to install the throat plate?

Sue, welcome aboard!

I use a blade out of my circular saw (7 1/4") to start the cut in the throat plate, and then move up to the 10" blade. Make sure you clamp a piece of scrap wood over the top of the throat plate so that it doesn't go flying out, and it prevents tearout on the top of the plate when the blade comes through! Good luck!

[Ralph Barhorst]

If your 10" blade is a standard 1/8" thick blade then use Jim's # 2 suggestion as the outer blade from a dado set is 1/8" thick.

If your 10" blade is 3/32" thick then use a smaller blade that is also 3/32" thick.

[Jeffrey Makiel]

I always used a 7 1/4" circular saw blade but it was always too thin. Never thought about using the blade from my dado. But, then again, I was never the sharpest knive in the draw either.

-Jeff :)

[Sue Wise]

Thanks for all the suggestions. The circular saw blade is a bit thin and I don't have a dado blade (but could probably borrow one), but clamping the insert on the old insert to begin the cut would work well. Thanks again for the help.

[Gary McKown]

I wouldn't use the clamp-over method to cut the complete slot because if you are off a little bit, then you end up with something more than "zero" clearance. I want the insert blank in place and adjusted for exact fit before cutting the slot.

You can use the circ. saw blade, then add a thin washer against the saw arbor flange to make a wider slot. If you stop the slot cuts so the 10" blade clears but before the thin blade comes through the top, then you needn't be too precise about the pre-cut slot width (so the clamp-over method would work here, too). Grizzly phenolic inserts have a ¼" wide pre-cut, in fact, so the same blank can be used for a normal ZCI or one made for a bevel angle, etc.

Don't forget to add some type of hold-down device at least to the rear of the ZCI. I like to use a positive-lock at both rear and front, so it is not likely to come out on its own.

[glenn bradley]

I assume you have one of the ZCI's that does not have the pre cut dado or you have made your own as I do. I have used 2 methods; put my dado on which is 8" and clears with no problem ( I raise it to within an 1/8" or so of puching through set for about 3/8" wide), If you have no dado blade for the TS, use the router table or free hand with a guide and slot the ZCI in the blade position to a depth and width that will allow installation.

The thing you DON't do is turn on the saw and lower the insert onto the blade :eek: . Once I establish the position to add my slots, I go ahead and do a half a dozen so they're ready. I mark my ZCI's on the underside with a felt pen as to; 24T Amana, 40T Lietz, WWII, Frued 80T, etc.

[Matt Guyrd]

Let me preface by saying I am far from being a table saw connoisseur, hence the seemingly simple question.

Is it common to have a contractor's TS in which a 10" blade doesn't lower enough to be below the table? Does this saw come stock with a 10" blade or smaller?

I'm sure I am missing something here...just seems odd that the blade would not be capable of lowering out of sight unless it wasn't designed for a 10" blade.

Regardless, sounds like enough good recommendations that the problem has been encountered before.

Thanks!
Matt

[Chuck Nickerson]

the top of the table, but not below the bottom of the table. These are the saws that need some relief on the bottom of a ZCI.

[Mark Rios]

Let me preface by saying I am far from being a table saw connoisseur, hence the seemingly simple question.

Is it common to have a contractor's TS in which a 10" blade doesn't lower enough to be below the table? Does this saw come stock with a 10" blade or smaller?

I'm sure I am missing something here...just seems odd that the blade would not be capable of lowering out of sight unless it wasn't designed for a 10" blade.

Regardless, sounds like enough good recommendations that the problem has been encountered before.

Thanks!
Matt


Matt, The blade on all of saws do, in fact, go below the plane of the table surface. However, some (most?) don't lower 1/2" or so below the table, which is the thickness (roughly) of a blank insert, especially a homemade one. This is an issue that all WWers will encounter at some point in their hobby. It can be very dangerous if done incorrectly but usually goes without a hitch when someone unfamiliar with the process asks questions about it before doing it, like Sue is doing here.

As some have mentioned, some ZCI manufacturers put in cut outs/kerfs in the bottom of their ZCI's to try to helpp deal with this situation. But some tablesaws have baldes that just clear the surface and one still needs to use a smaller blade or some other method to get the blade started.

hth

[Matt Guyrd]

Chuck...thanks! That makes much more sense to me. I didn't realize the distance between the top of the table and the bottom of the ZCI was so much that the blade wouldn't clear a ZCI in it's fully retracted position. I'll have to take note on my TS to see if I would run into this problem when replacing an insert.

Mark...just saw your response...thanks to you too! What a wealth of knowledge here!

Thanks again!
Matt

[Sue Wise]

Thanks Gary! Using a washer to make the slot wider is a great idea.

[Greg Sznajdruk]

I have noticed that Norm has a ZCI on his Unisaw. It appears to be made of metal with a replaceable center section. Can't find any source for this product. Anyone know a source for this ZCI?

Greg

[Don Fuss]

I use the clamp over method on my hybrid saw. There's a little trick I use to ensure that it's perfectly positioned, however. The original insert plate has leveler screws. If you retract those fully into the insert, the entire plate will sit about 1/16th of an inch lower than the table. That's enough to register the new ZCI in perfect position. I then clamp it down and make the cut.

[Kyle Kraft]

Good idea Don,

We have a Powermatic 72 at work and the blade cannot be lowered below the insert rest tabs in the table. The same is true of my Jet 10" cabinet saw. At first I thought something was wrong with my saw, but when I noticed the PM 72 at work (which is pretty old) did the same thing, I thought otherwise.

My FIL's Jet and Delta contractors saw share the same problem, BTW.

If I owned a company that made table saws I would change the design to make it safer for the user to make and cut their own ZCI.

[Kent Fitzgerald]

I have noticed that Norm has a ZCI on his Unisaw. It appears to be made of metal with a replaceable center section. Can't find any source for this product.
Greg, I know what you're talking about, and I'm pretty sure Woodcraft sold them, but I don't recall seeing them for the past few years. They cost close to $100, and I suspect that was just too pricy for the market.

[Jim Becker]

I have noticed that Norm has a ZCI on his Unisaw. It appears to be made of metal with a replaceable center section. Can't find any source for this product. Anyone know a source for this ZCI?

Eagle America carried it awhile back. Somewhat expensive to get started...I make mine from 1/2" MDF scraps.

[glenn bradley]

I route a groove on the underside where the blade will be. Another method would be to use a blade from your circular saw if the kerf is wide enough. Just don't cut all the way through or you lose the benefit of the ZCI conforming to the blade for which it is intended. Here's a commercial plate with the groove I copy:

http://ec1.images-amazon.com/images/P/B0002897MW.01._AA280_SCLZZZZZZZ_V39114701_.jpg (http://www.amazon.com/gp/product/images/B0002897MW/ref=dp_image_z_0/105-9228333-6099625?ie=UTF8&n=228013&s=hi)

[Hoa Dinh]

Sue,

It's probably too late for the current ZCI, but if you are making your own ZCIs (if you are not, learn how do it yourself), this is for next time:

I assume you use an existing insert as a template, and use double-sided tape to attach the template to the blank ZCI. After triming the new ZCI, don't separate it from the template. Instead, with the blade lowered all the way, put the whole thing in the blade opening with the new ZCI on top, clamp it down with a piece of scrap lumber, turn the power on and raise the blade.

That will cut a slot in the new ZCI exactly where it should be.

[Scott Patterson]

I used this link to build one from MDF for a dado blade on my Contractor's saw:

http://www.woodsmith.com/issues/146/...e-dado-insert/ (http://www.woodsmith.com/issues/146/videos/making-a-zero-clearance-dado-insert/)

Uses rip fence + wedges to hold the insert as blade is raised. Pretty easy and safe.

Regards,
Scott

[Mike Goetzke]

Greg, I know what you're talking about, and I'm pretty sure Woodcraft sold them, but I don't recall seeing them for the past few years. They cost close to $100, and I suspect that was just too pricy for the market.

Here's a review on them:

http://www.onlinetoolreviews.com/reviews/betterleytrucut.htm

[glenn bradley]

http://www.rockler.com/ecom7/product_details.cfm?offerings_id=10936

For $80 I'd make a shop made MDF body that would take 1/4" hardboard inserts. The advantage would be that the replacement inserts could be square and made quickly.

[Matt Anfang]

I was planning on making a few inserts this weekend, cause I'm to cheap to buy them from delta.

My plan was to just have some extra long set screws so I could raise up the ZCI to just above the blade and then clamp a piece of wood on top.

Any reason why that wouldn't work?