Flattening UHMW throat plate?

[pecker]

I made the mistake of ordering several UHMW throat plates during PeachTree's recent half price sale. For $8 it didn't seem worth making them from scratch.



Well, they are rather poor fitting, but since I will be making dado plates from them, it's not too critical.
However, they are bowed upward in the center about 1/32", which WILL affect how the stock rides over the plate, as well as the depth of the dado.

So, does anyone know a method for flattening these things? Maybe heating, then clamping them between two flat plates as they cool?

Thanks.

[steve-norrell]

Could you machine off 1/32 inch from the bottom of the plate and rely on the saw's table to support the piece you are cutting?

Alternately, if the TP is too tight in its slot it may bow upward when forced into position. Machining the ends and sides, using the OEM plate as a template, might fix the problem.

I have a BT3100 which has a square throat plate and is relatively easy to machine on a router table. I don't know if that would work for you.

Regards, Steve

[pecker]

Actually, they are poor fitting in the sense that they are small and flop around in the opening a little.

There are leveling screws, so I can adjust the leading and trailing ends below the saws surface, and just leave the central, bumped up area level with the main table. But I'd like to get them flat if at all possible.

[Cochese]

Could you attach the plate to something and plane it down? I think a plunge router and a straight bit would work well.

I don't know how that would effect the slickness of the plate, though. But when I had to router some UHMW for a guide before, it didn't affect it much.

[LCHIEN]

UHMW works well with wood tools. If its not too short then a small pass or two over a planer or jointer set to take off 1/64th per pass would flatten that in a hurry. That would certainly be the quickest, and you don't have a lot to lose at $8.

[Tom Slick]

You will not be able to "flatten" the UHMWPE with heat or pressing/clamping, you'll need to work with the warping. It's just part of working with a cast material that is soft, sort of like wood grain.

[herb fellows]

You will not be able to "flatten" the UHMWPE with heat or pressing/clamping, you'll need to work with the warping. It's just part of working with a cast material that is soft, sort of like wood grain.

I guess this comes under the heading of 'ymmv', I've had a different experience. It warps easily, but putting weight on it for a couple of days straightened out my 1/4" thick x 4" wide stuff.
Once it's straight, you have the saw as a 'sub base', so it should stay flat from there on out.

[pecker]

... and you don't have a lot to lose ...

My fingers, maybe?

Being somewhat flexible, the planer rollers would just press it flat. So I reluctantly tried the jointer on one of them. Since it is so slippery, I put a sanding sponge on it, then a sanding block on top that, to try to get a good grip while keeping my fingers away from the jointer knives.

After a couple passes, it was flat, but not smooth...many scallop marks. I may try sanding it a bit, but overall I think I've wasted my time and money.

The Leecraft phenolic plate I already owned is far superior to these plastic ones.
http://www.amazon.com/Leecraft-RG-1-...968375&sr=8-16

[LinuxRandal]

While I wondered about screwing it down upside down for a couple of days (see if it straightened out), I also wondered if you could just use some sandpaper, if it was only a little crowned? (might go through a bunch since it is plastic, but a sanding sponge might be handy)