Am I Playing Russian Roulette?

[Im A Little Petunia]

I am not sure I have done the safe thing, but let me tell you what I did and maybe I will have some input. I have made several zero clearance throat plates, but was not really happy with them. I was looking at the OEM throat plate last evening and got the bright? idea of making it a Zero clearance. This a.m. I went to the shop, took a piece of Lexan 1/4"x1-1/4"x 11-1/4", some carpet tape and the OEM throat plate. The carpet tape I used was reinforced with some type of fabric-like material (not the seemingly "plastic" type). I have used it before for holding wood together and have, at times, almost not gotten the two pieces apart - anyway I stuck the piece of Lexan to the back side of the throat plate, using a 2x4 placed over the plate I cut a zero clearance slot thru the Lexan. Everything went fine, it appears to be adhering very strongly to the throat plate and there it is! I have not had the "courage of my convictions" yet in using it. :-) What do you think? Is it safe?? Any advise before I fire up the saw?

Lynn

[Popeye]

That double sided tape may never give way, but if it does and the Lexan falls into the spinning blade then.... at best you're gonna think all **** is breaking lose and at worst shards of Lexan are possibly gonna come flying out at you.
One of the purposes of a zero clearance TP is to have a flush surface to run the stock over. From what you describe I don't see how this can be so. Just my two cents. Pat

[lrogers]

If I am understanding what you did, the saws standard throat plate is installed as usual with a piece of lexan taped the the underside? Correct??? I use the carpet tape frequently when making dupilcate parts and it is very strong, but I don't think I'd trust it in this application. The results could be "exciting", to say the least in the event of failure.

Having said that, I see nothing wrong with your general approach. I'd drill and counter sink a couple of holes in each end of the OEM throat plate, off set to either side of the blade, and add a small screw and nylock nut to make sure the lexan stays in place.

[Im A Little Petunia]

Yes Larry, you understood correctly. The Lexan is on the back side of the throat plate.I had thought about small bolts and nuts too, but the oem plate is so thin that I didn't think I could countersink enough to allow the head of the bolt to drop down enough to clear the surface without going completely through the plate. Any suggestions?

Lynn

[LCHIEN]

it sounds like your backing plate does one thing that a ZCTP does and that is prevent scraps and cutoffs from falling into the saw. If that's all you want then you have it.

OTOH, it does not support the cut piece all the way at the bottom, there is some space the thickness of the OEM TP that splintering will take place, another common purpose of the ZCTP.

If the carpet tape were to ever fail there would be a lot of bad things happeneing below the top of your saw... I'm not that big a fan of self-stick adhesives, they tend to fail over time and range of temperatures.

[herb fellows]

My 2 cents, Loring is 100% correct. It sounds like a short cut that has shortcomings, and the eventual danger factor on top of that would make it a no go for me.
If your luck is anything like mine, the day the s**t hits the fan will be the one cut you decided to hold off on putting on the safety glasses 'because this cut will only take a second'.
Much as we hate to admit it, I think we all do it once in a while.

[poolhound]

I am in agreement with the other posters. While DS tape is plenty strong for many applications I am not sure I would want to use it for this and you dont really get all the benefits of a custome fitted ZCTP.

They really are not that difficult to make. Doing them one at a time is a real PITA. What I (and I think many others) do is figure out our setups which is primarily the TS or BS for width and the router for the rebates and then batch cut a bunch of blanks. Creating a simple template for the holes is easy and you can drill through 4 or more ganged together.

Now you have a bunch of plates which you can cut for different uses and should last you a while. Its been over a year since I made my last batch and I still have one uncut blank left.

[dkerfoot]

Here is one approach from a very innovative BT'er:
http://woodworking.phruksawan.com/ec...CTP/index.html

It is a great idea, except for lack of support for the riving knife/blade guard.

[shoottx]

it sounds like your backing plate does one thing that a ZCTP does and that is prevent scraps and cutoffs from falling into the saw. If that's all you want then you have it.

I think there is a huge risk in Loring description. Adding the plate at the bottom to keep scraps and cutoffs out of the saw, means any cutt off or scrap that falls between the blade and the OEM TP will have to be "ground up" by the blade, before passing the ZCTP. It looks to me like an accident waiting to happen. If you get a bunch of stuff stuck in there it could create a lot of problems.

For me the value of a ZCTP is to reduce tearout and support the work piiece at the blade. My dust collecting and periodic cleaning take are of the stuff falling into the saw.

[massanutten]

Lynn, this is an accident in the making. Never compromise on safety for a few bucks - that's all it really is.

[Uncle Cracker]

Agree with all cautions given, and add that if the backing plate is shy of the surface by the thickness of the standard throat plate, the table surface will not be flat, and a catch is sure to happen sometime. It's OK to fabricate, but do the whole ZCTP as one piece.

[Im A Little Petunia]

Hello Everyone:
First let me say that everyone who has replied to my question regarding safety and the Lexan on the OEM t plate has been 100% correct! After Larry's reply I went out to the shop and took the Lexan off the OEM throat plate! I was surprised that it came off as easily as it did. Using it on a slick surface allows it to pull off much easier than I thought it would. I want to say that I appreciate the input from all of you. That is an idea that definitely did not pan out! Something told me not to use it until I asked someone else about it. a couple of things were mentioned which I had not thought about. I don't have a problem making the zero clearance throat plate - where the problem comes in is when I attempt to drill the holes so I can countersink the machine screw heads. I have tried drilling both before and after removing excess wood and I always mess it up. I don't have a problem with the placement of them - it's just getting the holes done correctly - the material that is left after removing what I need to on the throat plate , is so thin that there's hardly any thickness left for anything. Again, thank you all so much for your honest thoughts. Lots of heads sure are better than one in a situation like this - aren't they?? :-)

Lynn

[LCHIEN]

Use a drill press to both drill the holes and countersink. With a drill press it should be very easy to control the feed rate and depth. You push the countersink bit slowly, raise it from time to time and and use a flathead screw upside down to measure when the top of the countersink hole is as large as the head.

Make sure you use the right countersink bit angle, there are 82 degrees and 90 degrees, you need the 82 which is the sandard flathead screw angle.

[shoottx]

Hello Everyone:
First let me say that everyone who has replied to my question regarding safety and the Lexan on the OEM t plate has been 100% correct! After Larry's reply I went out to the shop and took the Lexan off the OEM throat plate! I was surprised that it came off as easily as it did. Using it on a slick surface allows it to pull off much easier than I thought it would. I want to say that I appreciate the input from all of you. That is an idea that definitely did not pan out! Something told me not to use it until I asked someone else about it. a couple of things were mentioned which I had not thought about. I don't have a problem making the zero clearance throat plate - where the problem comes in is when I attempt to drill the holes so I can countersink the machine screw heads. I have tried drilling both before and after removing excess wood and I always mess it up. I don't have a problem with the placement of them - it's just getting the holes done correctly - the material that is left after removing what I need to on the throat plate , is so thin that there's hardly any thickness left for anything. Again, thank you all so much for your honest thoughts. Lots of heads sure are better than one in a situation like this - aren't they?? :-)

Lynn

If you are the ZCTP is for a BT3K or equivalent don't use the end holes, use the hole the same as the factory ZCTP. Much easier. DAMHIK