Fence helper from the days of old (cutting Formica)

[reible]

This post has two parts, one being what I have and then an "issue" I had that you might have some ideas on. So stay tuned for a two part-er.

Sometime in the past I had seen what I thought was a good idea for cutting thin stock ie formica sheets or the like. I had done some of that type cutting and had some issues with doing it on the shopsmith (500 at that time).

The material is thin enough that it can slip under the rip fence. Can't say it happens with all machines but all of the ones I've seen seem to have the potential. When you get to the 520 I would have to say I think all of them are built with this problem by design.

By design I mean that there is a space between the table and rip fence large enough for thin materials to side under the fence.

To prevent this from happening a special fence is built with an aluminum "U" channel that captures the thin material preventing it from getting under the standard fence. Keep in mind this lifts that edge of the stock so works better at some distance to the blade. Since it is embedded in the fence you can not just measure from the fence and have the cutting distance. This is not much of a problem since the laminate is normally trimmed to size later on anyway.

So first some pictures and details. As I mentioned there is a "normal" space between the rip fence bottom and table. As seen here on one of my 500's:

[ATTACH]14065[/ATTACH]

In the next picture you see that this very thick piece of laminate has no problem sliding under the fence. If you attempt to rip the thin laminate to width the leading edge can slip under with no problem, well yes a problem for you as you wreck the material.

[ATTACH]14067[/ATTACH]

The extra fence face attached using the holes in the fence and a carriage bolts (bolts missing in photo but you get the idea). As you can see the channel sits on the table and the stock will slide in the channel.

[ATTACH]14068[/ATTACH]

Here is a shot of the fence face, size for the 500.

[ATTACH]14069[/ATTACH]

I now want to make one for the 520 fence. The major changes will be the holes have to match the t-slots on the fence and it needs to be longer. No problem on that account.

OK that is a brief overview and we can move on to the problem, in the next post.

[reible]

When I built this first one I knew I might be getting in over my head trying to get all the epoxy in place and the clamps on in time.

I did a couple of practice runs and it looked like I'd have at least a minute to spare. I believe I was using J B weld as that has been a favorite for years... how ever I can not be sure any more. It has a 4 minute set time.

I ruffed up the channel on the glue sides with sandpaper then clean it up.

I had test fit the wood and channel to be sure things fit. The surfaces that were not being glued I taped to keep them clean.

I mixed and then applied the epoxy to the wood, covering all the wood surface that needed glue.

I used about a dozen clamps to keep the channel against the wood surfaces in both directions.

I left it clamped for hours then removed the clamps. Set it aside and more hours later I went to remove the tape and notice this:

[ATTACH]14070[/ATTACH]

This amounts to 1/16" of error!

I thought of things that might have gone wrong but I never knew for sure which of them was the problem.

I thought maybe I didn't notice when I clamped it but I can't believe that as it is very large error to not see???

I though maybe the epoxy had hardened to quickly and the clamps were not able to over come this and I missed it happening???

Maybe the mix was weak on hardener and didn't set right, or I took the clamps off to soon???

I have used this fence addition by adding a washer between the fence and wood and it sort of works but I've never been happy with it. Now I've located the "U" channel again and want to do a redo.

My plan is to do a 500/520 version that has both mounting hole and is as long as the 520 (extra length is not a problem on the 500).

So anyone have any other ideas about what went wrong?

A better idea then this for cutting the thin stock?

Comments are welcome, even more so if they are helpful.

Ed

[stew]

The way I handle this problem is I set my rip fence on my auxiliary table and drop that table height a little below the main table. Set the width of cut and now the laminate can not get caught under the fence because it is touching the fence in the middle somewhere. This works for any cut except a small cut narrower then the main table.

Good Luck

[pennview]

Another option would be to simply add a strip of 1/8" thick masonite/hardboard or plywood to the bottom of your wooden fence to form an "L". This would work as well as the channel unless you're having a problem with the laminate riding up off of the table surface.

[beeg]

I can't tell if it's a bad cut on the end or a lack of glue. Next one cut long, then cut rabbit. Trim to length and when gluing, use plenty.

[forrestb]

I have used West System 105/205 to successfully bond an Al strip to fir. They recommend that you first coat the wood and give it a few minutes to soak in before applying the final coat and the Al. They also recommend coating the Al with epoxy. They recommend an Al cleaner but I did what you did: sanded and cleaned with acetone.

Of course, the West epoxy is very thin and has a pot life advertised at 10 min. but I found that by mixing the epoxy on a flat sheet of glass rather than in a cup I got a longer pot life due to less heat concentration.

I also used spring clamps about every 5 inches.

West sells a 'kit' 101-TS Epoxy Packet but it only comes with the fast hardener 205. You get 13.75 ml of 105 and 2.75 ml of 205. Saves having to measure anything.

Good Luck

Forrest

[jondann]

I use a plastic strip intended to join two sheets of thin wall covering (as might be used in a bathroom). It is about 1 1/2" wide and has a mushroom shaped ridge in the middle and costs a few dollars for an 8' piece. I cut a piece the length of the rip fence and put one flange under the fence. The thin material rides on the other flange against the ridge.

[bffulgham]

My solution to a similar issue.....
I like to use a framing square on my 510 to set my rip width....the gap under the fence allows the square to slip under (Attachment IMG_9974).

I use a scrap piece of 3/4" cabinet grade plywood as an aux fence (Attachment IMG_9975).

No more gap. Close-up: (Attachment IMG_9976)

[Ed in Tampa]

Why not use a piece of F channel made for holding up aluminum sofia on a house? It is shaped just like an F so you could mount the tail to the fence and have in effect u channel on the bottom like you do now. No epoxy needed. Less likely to bent to conform to any warpage.

Also have you considered anything like a Unifence they have a part that can be used for very thin stock that allows you to get you fingers down there to hold it. Yet can be taken off and reinstalled to provide a perfectly smooth face to rip thicker stock. Basically it is an L where the horizontal leg of the L is used for thin stock and then flipped upside down and mounted to the fence the vertical side of the L now becomes a fence face for thicker stock.

Or have you thought of using a smaller L stock and mounting it to your fence. instead of the U channel. Mount the vertical side of the L to the fence in a shallow rabbet and the bottom side of the L would act like the bottom side of U channel you are using. Again you could use counter sunk screws and eliminate any need for epoxy.

Or am I missing something?