LARGE BIG TS Sled w two guide bars OR against Fence ??

[Marc Jeske]

Still digging through Google images and Youtube videos.

Have 45 ? yr old PM Contractor saw w 52" Biesemeyer.

May be upgrading in future to D/R 12/14 w Bies 52 .. will decide BEFORE I do any "permanent" ext table design/ install.

It stays stationary and never has to move... Plenty of clearance ALL around.


Want to regularly crosscut one foot of length off of 16" x 8' panels...so end up w 16" x 7'.

I purchase them at already 16"... Factory ends may not be perfectly square.


First question - Why do I never seem to see sleds that bear against the Fence as the guide ?

Always they use the miter slot.

Remember, in my case I am only cutting off one foot to the right of the blade... not something over the "52" " reach.

Seems to me one could make a sled w an extended fore to aft right edge that would seem to work.


Second question - How realistic is it to make a sled that uses BOTH slots w no bearing on fence ?

Concerned about binding in a fluctuating ambient humidity.


So basically I am brainstorming about making a poor mans equivalent to a Rolling Table or Euro panel saw really mostly kinda only for the job described above.

Commercially available like Excaliber, Sawstop etc "Sliding tables" are too expensive for my taste.. especially not being very large.


Currently, I use a dedicated piece of ply 8' x 2' w a back fence and 90 deg guide bar I run the little PC worm saw against.

Works fine but would rather be able to do on TS.

I do have the floor space around the saw no problem

Lastly.. I have learned occasionally on some large panels to sprinkle a tiny bit of blasting Potters glass beads to act as microbearings.. works great for occasional work.

So for the not often I need to do this, that could be employed in addition to good waxing.

I will be building ext tables around infeed, left side, and out.. so my left table will support this sled.

Comment please.. mostly on the two specific questions to start with.

I think I gave all pertinent info, please read carefully.. if not.. ask.

Thank you all very much, Marc

[Ken Fitzgerald]

Answer to 1st question, I adjust my fence so the far side splays to the right a couple thousandths so boards can't get trapped when I am ripping them. I wouldn't want a sled riding against the fence.

Answer to the 2nd question, my sleds do use both miter slots and don't use the fence.

Lastly, personally, I would not use glass beads as I would not want to take a chance on inhaling any or any particles they might generate if they accidentally came into contact with the blade. I wax the tables on my T/S, B/S and scroll saw.

[Tom M King]

Sorry, I don't have an answer about the best way to make that cut on a TS. I would use a RAS. No way would I feel comfortable making that cut on a regular TS. I'd make a dedicated rack to cut it with a circ saw, if I didn't have a RAS.

Is your PM contractor saw a model 62? I still have one that I bought new then. I've never seen another one.

[Brian Holcombe]

Sprinkling glass beads is going to destroy the machine, it would be prudent to discontinue that practice.

[Marc Jeske]

The glass beads never get within a foot of the blade.

They are used very methodically in extremely small quantity...less than 1/8 tsp.. Never used for repetitive cuts where they would in that case migrate "everywhere" including blade.

So ya, NO problem.

Tom M .. Pretty sure it is a #62 AFAIR.

And, I did say I already currently use a dedicated "Rack" w a PC little circ saw.

Ken... RE inhaling... I have given now more detail on the use of them in this post.

My Daughter in Phoenix inhales more Silica in ONE day during their "Dust Storms" than I will in a Lifetime.

I choose to leave my fence closer to parallel.. not perfectly... but close enough to ride against for realistic "90"

Please talk about a sled using two slots works out if in fluctuating ambient humidity.

Interested in that.

Marc

[Marc Jeske]

The glass on table, the < 1/8" tsp.. is swept off to the left after rare use.

It is ONLY applied to left of blade... NONE to right of blade..NOT within 1 ft of blade... and VERY sparingly.

Not like when I eat Spaghetti and use 1/3 jar of Parmesan !!

Marc

[Marc Jeske]

Tom - Thing is... I need to do the same thing on my 28" Casket lids as the 16" sides.

RA is too small a reach.

Marc

[Cary Falk]

1) A sled that rides against the fence can rotate out into the blade and bind then kick back. This would be even harder to control with a 7' board hanging off one end. No way I would want to use the table saw. If you have the room find a DeWalt 790/7790 with a 16" crosscut for $100-$150 and use it. If you don't have the room. Make a jig that you quickly rreference and cut off the piece.
2) People use 2 runners on large sleds all the time.
3) No way would I want glass bead near my tools. A good wax should be good enough.

[Lee Schierer]

Want to regularly crosscut one foot of length off of 16" x 8' panels...so end up w 16" x 7'.

First question - Why do I never seem to see sleds that bear against the Fence as the guide ?

Always they use the miter slot.

When you put your panel or a sled against the fence you have no garuntee that it will stay tight to the fence. The drag to the long side of the piece will tend to make the piece want to twist as you slide it across the table. As you know any binding not only ruins your cut but it can be dangerous.

With runners in one or more of the miter slots the crosscut sled cannot twist relative tot he blade, hence no binding and no kick back. You can use a stop block or short fence to set your cut off length for repetitive cuts.

Waxing your table surface will make the sled slide more easily and also helps keep your saw table clean and shiny.

[Peter Christensen]

As I understand you, using the fence to run the sled against over time, because you can't always get the fence in the same place every time you use it, your blade slot gets bigger and bigger. That would provide less support beside the blade increasing the splintering of the cut edges. As Cary said the sled can come away from the fence and kickback. That could be overcome by having a U shape on the end of the sled that fits over the fence but you still have the problem of locating the fence.

The two runners work fine especially if you keep them waxed. If you have a seasonal humidity problem make the runners out of something that doesn't get affected by moisture. Corian, UHMW (the 3/8" x 3/4" x 48"LV sell for example) steel bar stock, pre-made runners http://www.leevalley.com/en/hardware...76,61994,61986 or http://www.leevalley.com/en/wood/pag...47&cat=1,43455 .

I wouldn't use the glass either. Talcum power if anything. I have never needed anything more than paste wax or a wipe with a bar of canning/candle wax. Don't use Pledge or similar. They have silicone in them that plays havoc with film finishes.

[Ken Fitzgerald]

Marc,

Where I live we get 13" of moisture annually. Fluctuating humidity is not much of a problem but you don't have to use wood for the runners for the miter slots. I use quarter-sawn wood, finish the miter runners and the bottom of the sled. Then I wax the runners and the bottom. My poly finish is thinned and still has the desired effect.

For the record, my fence is very close to 90º to the rail end but 0.001-0.003" at the far end of the fence isn't going to cause much of a problem at the blade where the ripping takes place.

[Ken Fitzgerald]

Marc,

where I live, we only get 13" total annual average moisture so relative humidity has little effect here. You don't have to use wood for the runners but I do. Then I put a thinned coat of poly on the bottom and runners followed by a couple coats of wax.

My fence is very close to 90º as 0.001-0.003" at the far end of the fence has very little effect at the front edge of the blade where the cutting is taking place when ripping.

[Rick Potter]

Sounds to me like a good use for the Festool track saw with their MFT, or, heaven forbid, the new Kreg track saw and table setup.

[Marc Jeske]

OK, so consider me argumentative.

Pretty familiar w the issues explained above.

Been there ... done that.

I have crosscut one foot off the end of many 4x8 panels along the fence w minimal trouble....

HENCE - Why can't I build a sled w a over length... lets say 4' edge that rides along the fence ?????

Please think about that before giving an answer to it.

Marc

[Marc Jeske]

Rick - Again... I already have a dedicated jig as I clearly described above to do the equivalent of this.

Marc