How about a sliding outfeed support for TS?

[Noah Katz]

I'm just about to start mounting some heavy duty 36" drawer slides on either side of my PM2000's cabinet, with a cross-support the width of the saw to support the end of stock as feed it.

It seems so simple that I can't imagine nobody has done it before, so I wonder if I'm missing some obvious reason not to do it.

The stock support will 1X4 or 2X4 with a piece of UHMWPE on top.

To make sure the slides extend instead of the stock just sliding over it, there will be some thin springy material attached to the back face.

The stock will push against it and extend the slides, and if the slides reach their full extension (will only happen with more than 8'), the stock will just push it out of the way.

There will be some light return springs or maybe a counterweight & pulley to make it self-retracting.

The advantage is it won't need to be deployed like a folding or rolling outfeed table, and it will keep me from having a surface to clutter up.

I'm going to see if I can work in one or two floating cross pieces so long stock has intermediate support.

So what do you think?

[Jamie Buxton]

That's a slick idea.

Strong slides would be a good idea. You might consider Accuride's 9301 series. They can be had up to 60" long, and are rated for 400 pounds. http://www.accuride.com/products/industrial/details.php?p=9301&c=heavyduty_ie I believe Rockler retails them.

[Roy Harding]

That IS slick!

I'll be interested to hear how you make out with it - perhaps a patent is in order?

Roy

[SCOTT ANDREWS]

That IS slick!

I'll be interested to hear how you make out with it - perhaps a patent is in order?

Roy

Don't suppose you would provide us Creekers a drawing of it before the patent.At least some detailed pictures.I too would like to know how that turns out.

[Jason Beam]

~~~~ Monkey Wrench ~~~~

1. You're gonna have to make sure those things are DEAD parallel to your blade so that they don't lead the stock into kickback land.

2. A spring might get stronger and stronger as you push further and further past the blade. This could actually push the wood BACK into the back of the blade into MAJOR kickback world. Counter weights may work a bit more uniformly.

3. A minor thought about the intended space savings. You'd still need x inches of untouched space at the level of the slides out to their extensions. This basically means you could still stick something back there, just shorter than the height of this system to allow it to pass over. Maybe a jointer, set low enough? The space would still be of (possibly slightly) limited utility.

4. The springy backstop is the interesting part .. it has to be strong enough to extend the slides but weak enough to yield at the least bit more presure and still stay in place with varying feed rates. This, to me, seems like the biggest challenge to get dialed in. It has to be able to take the weight of the piece, which may introduce some resistence that might be a factor.

~~~~ Monkey Wrench ~~~~

It sounds like a great idea. It may take a few tries to get everything working perfectly. I'm very interested to see the progress of this one. All the great ideas I see anymore always leave me with "Huh, why didn't someone come up with that sooner?" This idea has me thinking similar thoughts. I hope it works out and I can't wait to see it in action!! :D

[glenn bradley]

I believe it was Wood magazine that had a similar setup. I'll see if I can find the issue number. Their's was just a slide out extension that pretty much stayed put once in position but it could give you some ideas on mounting methods, etc.

[Noah Katz]

"You might consider Accuride's 9301 series. "

Thanks, I already got them on ebay, $55/pr, 250 lb capacity IIRC. 3" high, same as the Accuride.

"I'll be interested to hear how you make out with it - perhaps a patent is in order?"

Not worth the hassle and expense to me, if it's even patentable.

"1. You're gonna have to make sure those things are DEAD parallel to your blade so that they don't lead the stock into kickback land."

Hmm, interesting point.

Do you think it's any different than a roller support that's not perfectly parallel to the table?

Another good reason for having the UHMWPE top piece.

Also I have Board Buddies, so that should help.

In any case, you just saved me some work; I was thinking of tilting them in from the vertical to increase lateral stiffness.

I'll just leave them fully vertical. I think the first couple of feet should be fine before there's much stock past the end of the table, and after the slides are extended that much they get pretty flexible laterally.

Shoot, I just remembered that the other reason is so the slide fits above the motor cover....

"2. A spring might get stronger and stronger as you push further and further past the blade. This could actually push the wood BACK into the back of the blade into MAJOR kickback world. Counter weights may work a bit more uniformly."

Right, exactly why I'd use a counterweight.

I should probably just nix the auto return altogether; it won't be that hard to just push the slides back in.

"3. A minor thought about the intended space savings. You'd still need x inches of untouched space at the level of the slides out to their extensions."

Yes, but I can touch it whenever I'm not cutting long stock :)

"4. The springy backstop is the interesting part .. it has to be strong enough to extend the slides but weak enough to yield at the least bit more presure and still stay in place with varying feed rates. This, to me, seems like the biggest challenge to get dialed in. It has to be able to take the weight of the piece, which may introduce some resistence that might be a factor."

The spring need only be strong enough to overcome the slide resistance.

I just clamped a slide in a vise and hung a 45 lb weight at the end and extended it the full 36"; only a couple of lb of force at most was all it took.

I was thinking a piece of thin plastic, spring steel, or whatever, held on with a clamping knob so I could swing it down out of the way if I want.

Now that I think about it, I could start with a long piece and clamp it at an angle, increasing its effective length and compliance; once I find an angle that works well I cut it to proper length.

Or a hinge with an adjustable spring, perhaps make it over-center, again so that I could get it out of the way.

I appreciate everyone's feedback (Glenn, please do post the Wood article if you find it). Nothing sufficient to dissuade me yet, so I'll proceed.

I'll post results with pictures.

[Doug Shepard]

Interesting idea. Finding the right springs for this may prove very difficult. I recently went through a fair amount of trial and error finding some to spring-load some blastgates which only had to extend 6-8". If I understand how you intend these to work, you need the deflection on these to be 36". Short of getting something custom-made, my guess is that anything off-the-shelf you can find with a 36" deflection is going to already be longer than 36" to start with or be of a larger diameter that would be too strong (issue #2 noted earlier).

McMaster-Carr has a pretty large selection. Go to
http://www.mcmaster.com/ (http://www.mcmaster.com/) and type 1147 (catalog page) in the Find box. There's some good extension spring info on that page. Wasn't able to spot anything there that looked usable though.

If you go on Century Spring's site
http://www.centuryspring.com/Century/GateWayServlet?destination=MainCatalog.jsp (http://www.centuryspring.com/Century/GateWayServlet?destination=MainCatalog.jsp)
and scroll down to the extension springs, you can play with the specs to see what they have available. I struck out with a 36" deflection but was using 5 Lb for the Load parameter. They might have something else close that would work though?
They've also got some FAQ stuff here
http://www.centuryspring.com/pdfs/techfaqs.pdf (http://www.centuryspring.com/pdfs/techfaqs.pdf)

[Dave Morris]

Noah, although that sounds like a cool idea, I'd be VERY leery of having any "return" pressure on the material being cut... counterweight, return spring, or whatever. Any vibration of the saw would make the material that much easier to move back and contact the spinning blade teeth. The potential for kickback seems more probable than possible. (Yeah, it's a PM 2000, but a nickel can move/roll while still passing the nickel test, eh?)

The extendable outfeed support is a great idea, but how much trouble will it be to simply push the support back when you are done using the saw and have to walk behind it? Or... attach a string, run it under the table on one side of the saw, and pull the support back if you need to. Once the cut is done and the blade has stopped spinning, there's no potential for kickback.

Something akin to the workings of a roll-top desk could be made to fill the gap as the slides extend, so shorter pieces wouldn't fall between the back of the saw and the end of the *extended* support. Also, maybe use three slides instead of two, so the material spanning the width of the outfeed doesn't bow down in the middle? One slide on both sides of the saw cabinet, and one at the far end of the fence rails.

Not saying it's a bad idea, just playing with the idea in my head to try and identify potential problems for the sake of safety. I'll be interested to see what your final design looks like.

[Noah Katz]

Yeah, I'll just forget the whole return spring idea.

"Something akin to the workings of a roll-top desk could be made to fill the gap as the slides extend, so shorter pieces wouldn't fall between the back of the saw and the end of the *extended* support."

After looking at the slides and thinking about this some more, I'm going to attach one cross support to the end of the fully extending slide, and one to the end of the middle section.

The former catches the board as previously described, and after it extends 18", the latter starts to extend, so there will never be more than 18" unsupported.

"Also, maybe use three slides instead of two, so the material spanning the width of the outfeed doesn't bow down in the middle?"

The cross supports will be 1"x2"x1/8" rectangular steel tubing, 48" long with about 3' between the slides.

Max deflection with 50 lb load is .0024".

[Noah Katz]

I can also counteract sag of the slides by inclining them slightly upward toward the back to compensate as they open.

[Dave Morris]

<<<< The cross supports will be 1"x2"x1/8" rectangular steel tubing, 48" long with about 3' between the slides. >>>>

<<<< ...counteract sag of the slides by inclining them slightly upward... >>>>


Okay, methinks think you got the sag pretty much covered. ;-)