Ripping long thin stock safely

[Jamb]

What is the safest way to rip a 8ft x 3 ½in x 5/8in thin MDF in half to get two 8’x3 ½”x ¼" strips ...or trim off ¼” to get a 8’x3 ½”x3/8” piece? How would you do this cut?

Akos

[mdutch]

0. Start with your stock oversized -- square on two faces and NOT cut to length. Saw your plank's width first, then rip for thickness, then trim to final length!

1. It's imperative that your fence be completely parallel to the blade. (See the manual AND setup instructions by users in the Articles section of this board).

2. I'd suggest you have a pair of feather-boards to keep your stock against the fence properly.

3. Decide which cut you want -- the 3/8 vs the two 1/4" rips are different setups. You need to determine the kerf width of the blade. If it's a 1/8 kerf and you've got a 5/8 thickness, you can rip the board once and get your two 1/4's if you set up the rip correctly. Don't guess on kerf width -- make a cut in a scrap and accurately measure it. (I use an inexpensive plastic micrometer extensively to check small measurements on my saw.)

4. If you're determined your cut can be done in one bisected rip-cut, use scraps of the same dimension to set up your rip: Making a tiny end-cut, flipping the piece over with the inside-blade face on the outside and make a matching cut on top of the other, to see if the blade is really centered. You can make fine adjustments.

5. You need an excellent ripping blade for composite stock. I'm NOT an expert here, but I know the stock blade with the BT3K will do the job well.

6. Don't put the blade higher than you need to. The bottom of the teeth should clear the top of the stock, no more.

7. Support your outfeed stock with roller-guides, or a table so you don't get distracted by your piece moving on you at the end of your cut.

** (There's lots of info on the most important part of woodworking, milling your stock square on four sides. here's one link I like!)

GOOD LUCK!

[Jamb]

Start with your stock oversized -- square on two faces and NOT cut to length. Saw your plank's width first, then rip for thickness, then trim to final length!

This is interesting. I would cut it to length first. Isn’t it easier to rip a shorter piece than a long one?

Decide which cut you want -- the 3/8 vs the two 1/4" rips are different setups. You need to determine the kerf width of the blade. If it's a 1/8 kerf and you've got a 5/8 thickness, you can rip the board once and get your two 1/4's if you set up the rip correctly. Don't guess on kerf width -- make a cut in a scrap and accurately measure it. (I use an inexpensive plastic micrometer extensively to check small measurements on my saw.)

The exact size is not crucial. I have a few of those pre-made but I want them a little thinner. They can be between ½” and ¼” as long as they are all the same. Why is the setup different?

I have a feather-board (first project on the BT) to push the stock against the fence but my main concern is kickback. I have to remove the blade guard with the splitter for this cut and I am afraid, the pieces will close behind the blade. If I decide to cut them in half, there will be a ¼” piece between the blade and the fence? How do you push it through? A push stick gets dangerously close to the blade, doesn’t it?

What if I want to keep a 1/2” thick board? I think the kerf of a Ryobi/Freud blade is 1/8”. Can I just make sawdust of the 1/8” cutoff or it is not the right way?

[JimD]

I always use a splitter but seldom use a guard. It is certainly better to use both, just saying what I do. I would be least worried about lack of both in a composite material like MDF. Solid wood tends to be warped which is what causes the kerf to close down pinching the blade. Composite material is not normally warped, particularly not MDF. I would be more comfortable with a splitter, it still helps with kickback by keeping you aligned with the blade, but if you had to cut without one, MDF is what I would want to cut. I think you can buy a splitter from the shark guard place. I made mine out of 0.090 inch thick 6066 T6 aluminum from McMaster Carr. I used the stock splitter for a pattern but made it shorter so it can stay on the saw unless the dado blade is on the saw. Only took a few minutes but if you only want one it may be just as cheap to buy it already made.

My normal way to work is to put the piece I am keeping up against the rip fence. I have push sticks in varying thicknesses and would probably use the 1/4 inch wide one for this cut. You should have a push stick of some sort handy whenever you are making a fairly narrow rip so you avoid the temptation of getting your hands too close to the moving blade.

It does not affect accuracy with the saw set up right to only trim off a little bit. If anything, I tend to make these cuts more easily accurately. You don't have to worry about the off-cut piece pulling the material out of alignment with the blade.

Jim

[gary]

What is the safest way to rip a 8ft x 3 ½in x 5/8in thin MDF in half to get two 8’x3 ½”x ¼" strips ...or trim off ¼” to get a 8’x3 ½”x3/8” piece? How would you do this cut?

Akos

Safest would be to resaw it on a bandsaw.

[Brian G]

They can be between ½” and ¼” as long as they are all the same.

If that's the case, then I'd buy a sheet of 1/4" MDF, cut with a circular saw about 3.75" strips (one from each edge so you have the factory edge that goes against your rip fence), and then rip it to final width with the tablesaw.

That would be safer and less harsh on your blade than trying to resaw MDF.