Problems w/ warping on Powermatic table saw fence (Pics included)?

[Porter Friedman]

I've had this problem for the year and a half that I've had my PM-1000 saw and am interested in seeing if others experience it as well, and if so, how you deal with it... Seeing as powermatic uses the same UHMW material on all of their fences, I cannot be the only one?

Basically, the plastic warps pretty significantly not only where the t-bolts hold it to the fence, but especially on the front and back ends. I've included some pictures that are hopefully good enough to see what is going on. When holding a straight edge to the fence, there is an easy 1/16" gap in the middle. This ends up causing lots of problems first of all when measuring, as its hard to adjust the fence and accurately measure from the blade when the plastic wobbles in and out across its entire length, but also when pushing longer stock through the saw as the end of the fence pushes the material into the riving knife and blade. It does seem to be more prevalent in the colder months (unheated shop, 40-50 degrees F).

for a high-end saw, I am finding this very frustrating and pretty unacceptable. Does anyone else experience this? Have you found a solution? Yes, I've tried adjusting the t-nut tension.. No help there.

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[john bateman]

If it were mine, I would just replace the plastic with something more stable, such as melamine coated particle board.
But if you really want the plastic, maybe buy some from a 3rd party and cut it to fit. It's not that expensive:
http://www.usplastic.com/catalog/item.aspx?itemid=23217&catid=868

Of course theirs may deform also.

[Andrew Hughes]

Have you checked the metal surface that the plastic is screwed to is flat?
If it is not then your just gonna have to flatin whatever you attach to it.
I used to have a lovely piece of Yellow cedar attached to my Fence on my Unisaw.Once a year I would true it up to perfection with my foreplane.
This is my experience

Aj

[Dick Brown]

You could countersink some self tapping screws between the existing fasteners to help hold it straight but a better option in my opinion would be replace it with Baltic Birch and Formica or some other more stable material. I build a fair number of Biesemeyer type fences and really like Corian or other solid surface material but it is tough to find most of the time. Seems to be very stable.

[Robert Hayward]

Have you called Powermatic and talked to them ? I thought all Powermatic saws used in a home shop carry a five year warranty ?

[Porter Friedman]

Have you called Powermatic and talked to them ? I thought all Powermatic saws used in a home shop carry a five year warranty ?

I did call Powermatic and they seemed to have never heard of the problem.. I bought the saw "scratch & dent" so it unfortunately does not come with any kind of warranty.

[Porter Friedman]

Luckily the metal fence itself is perfectly straight.. I guess I just need to make some new faces for it.

[Andrew Kertesz]

Have you checked the thickness of the UHMW? Could be that it is not warped just not a consistent thickness as it is not a cast material....

[Mark Wooden]

+1 on replacing it. I use a sacrifical hardwood ply or hardwood, well waxed. It allows me to screw featherboards, stops etc. to it and when it gets beat, not hard to re-do.

[John McClanahan]

+1 on replacing it. I use a sacrifical hardwood ply or hardwood, well waxed. It allows me to screw featherboards, stops etc. to it and when it gets beat, no hard to re-do.

Mine was the same way when I bought my used PM66. I replaced the left side with a strip of good quality plywood.


John

[Cary Falk]

You could also replace it with a piece of extruded aluminum. I have a piece from Rockler that is as straight as I can measure with my precision straight edge. It won't be as pliable as the plastic.

[pat warner]

HDPE is never flat nor of uniform thickness, unless machined that way.
Moreover, it can bend/deflect at the fasteners.
The only thing it's got going is slip.
So I'm not surprised you're having trouble.
You can plane it, however!
But better choice would be machined Delrin.
And in my view, aluminum extrusions are not flat unless they are machined.

[Martin Wasner]

I have that fence on one of my saws. I hate it with a passion.

You could take the whole fence to someone with a mill and flatten it out.

Make a new face from Baltic birch, and laminate both faces.

I've got a scrap of Richlite I've been meaning to mount. It should be stable and slippery, but it's black. I'm not sure I'd like having a black face on the fence.

[John TenEyck]

I did call Powermatic and they seemed to have never heard of the problem.. I bought the saw "scratch & dent" so it unfortunately does not come with any kind of warranty.

Well that's not surprising. But really, if the fence is flat either joint/plane the plastic flat and true or replace it with wood/plywood. Not to be rude, but I would have fixed that the day I found the problem. You can't do quality work with it like that. Make it right.

John

[Joe Jensen]

Take the plastic off the fence. Put some auto body filler one the sides and once hard, use a flat board with stick on sand paper to flatten it. Go slow and check often to square and flat. Once you have it flat put the faces back on and they will be flat. The steel tube should have been grown flat first. The original Biesemeyer fences were.

[scott spencer]

Some options:
- shim the faces
- flatten the faces (jointer or drum sander)
- replace the faces

[Porter Friedman]

Yea, I luckily have some scrap 3/4" baltic birch and some wilsonart laminate lying around. I suppose its time to bite the bullet and make some face plates for it. I am just surprised that a top tier saw would stick with a fence that causes problems like this..

[Joe Jensen]

Yea, I luckily have some scrap 3/4" baltic birch and some wilsonart laminate lying around. I suppose its time to bite the bullet and make some face plates for it. I am just surprised that a top tier saw would stick with a fence that causes problems like this..

Before you make new fences, make sure the tube is flat and straight. Otherwise the new baltic birch will warp too.

[Martin Wasner]

Yea, I luckily have some scrap 3/4" baltic birch and some wilsonart laminate lying around. I suppose its time to bite the bullet and make some face plates for it. I am just surprised that a top tier saw would stick with a fence that causes problems like this..

First mistake is thinking that powermatic is top tier. That never has, and likely never will be true. Mediocre is a fair assessment of powermatic quality in most instances.

And yes, I have a bunch of powermatic equipment.

[Andrew Hughes]

I doubt Powermatic would be able to satisfy me.Im really picky being a perfectionist comes with a price.:)
I also have a Powermatic planer and bandsaw.

[Tony Leonard]

Yep, my PM2000 has the same issue. I played around trying to overcome it with shims, but it didn't really work well. To be honest, it has never been an issue. I don't like it, but my cuts are fine and it doesn't hurt anything. It has been on my to-do list for years, but I haven't gotten around to fooling with it. I like the slick surface. I used playing cards as shims and was able to get some of the "waves" out but it is still not perfectly flat. Maybe I'll get back to it....someday!

Hmmm...I have a CNC router..perhaps I can just skim the surface with it. That's probably work. Need to figure out how to reference it first though. I never have messed with the other side of the fence since I rarely (maybe once) use it. Could take it off and use the extrusion as the reference. Something to think about...

Tony

[Justin Ludwig]

Threw my UMHW fence away a long time ago. Was junk. I replaced it with a homemade laminated MDF that was taller. No problems since then.