Cutting up an 8' x 4' panel

[chrispuzzle]

This may seem like the dumbest of dumb questions, but how do scrollers recommend cutting up an 8' x 4' panel given a small workshop area of 10' x 10' - although the back yard is available.

For example, is my BORG jigsaw OK or would I be significantly better off with a low-end circular saw? How many trestles do you usually use to hold the board? Do you cut it down the middle or do you cut from one end? Can you stand it on edge and cut vertically to save space...? Is there a significant difference to your method when handling 1/4" as opposed to 1" board?

Chris, who is not remotely a carpenter

[Daryl185]

Chris I would highly recommend a min of 4 saw horses a circular saw and some helping hands to hold the ends as you cut them

[PuzzledMoose]

You could probably do it with a jigsaw, Chris, though it would be easier with a hand held circular saw - preferably one with a plywood blade (lots of teeth!)

I usually put 4 lengths of 2x4 under it - two fairly close together either side of the cut and then two at the edges of the board. I find it's faster to clamp a straight edged piece of wood on the top of the board to act as a guide for the saw.

Hope this helps - and this is with the proviso that I ain't a carpenter either ..:-)

[stevebuk]

hi chris
depends on what size board you want to work with, but i would tend to cut from one end only using a handheld circular saw or jigsaw, both are inexpensive nowadays.
steveb

[Gill]

Hi Chris

I usually get the retailer to cut mine.

If that option isn't open to you, I find a couple of cheap 'workmates' with their jaws open (and a couple of clamps to fasten it) will support an 8x4 board quite happily while I tickle it with a cheap hand saw. I've never cut an 8x4 1" thick board before but I've never had any problems with 18mm.

Hope nobody minds me mixing imperial and metric measurements - it's not unusual on this side of the Pond .

Gill

PS However you cut your panel, it's a good idea to score the underside first with a craft knife to prevent tear out as you cut.

[sawdustus]

how to cut 4x8 ply sheets

Chris,

Between my own house, my three kids houses, and lots of inlay puzzles for my granddaughter, I have cut dozens of sheets of ply.

I usually use a small circular saw for 1/2" or thicker ply and a jig saw for 3/8" or thinner. The weight of a circular saw can bow the thinner ply and throw off your cut or actually bind the saw in the kerf causing kickback.

You can get away with 2 horses, 3 are much better, and 4 is great, but don't overhang the end you are cutting too much( about 18" if cutting the short dimension) because unless you have someone holding up the offcut, it gets very heavy and unwieldy.

Puzzled Moose's suggestion of 2x4's is what I have always used. Works for sheetrock also. I also put them on either side of the cut line for support.

I also clamp a long straight edge to the plywood to guide your saw. Makes for less waste and usually eliminates the need to retrim after you have cut to size. If you use a spare piece of lumber, make sure there are no bows in it.

Good luck and remember that the only dumb question is the one you don't ask because you don't know the answer and are too embarassed to ask.

[Bill Wilson]

Here's my method for cutting down 4x8 sheet material. I use 2 sturdy sawhorses (trestles). I lay four 8' long 2x4's across the saw horses and lay the plywood flat across the 2x4's. If I'm making long rip cuts, I space one 2x4 just on each side of the cut and one under each of the other edges of the sheet. This gives me two 2x4 supporting both pieces.

If I need to cross cut the sheet, I take several shorter lengths (4' long) of 2x4 and put them perpindicular to the 8' boards and arrange them in a similar fashion, relative to the cut. This method prevents binding and sagging of the material, regardless of what type of saw you use.

As for the actual cutting, I use a 7 1/4" circular saw. With a good plywood blade, you will get cleaner cuts faster than with a jig saw, but a jig saw will work as well. If you can find a straight edge at least 8' long, you can use it as a guide to make very straight cuts in the sheet. There are a few different types of jigs setups you can use. You can even buy commercially made straight line cutting jigs, but the simplest is to use a cutoff of another sheet of plywood at least 1/2" thick by at least 3-4" wide by 8' long. it must have one factory edge. Clamp this straight edge securely to the sheet at each end. You will have to offset it from your cut line by the distance between your saw blade (taking into account which side is waste) and the edge of the saw base. The saw will ride along the straight factory edge, right down your cut line making for a very precise and straight cut. You can use the same technique for cross cuts and use a shorter straight edge, if available. I hope I explained this well enough. If not, reply and maybe I or someone else can make it clearer. Good luck.

Oh and a word of caution, if you use a circular saw do not over reach trying to make the long cuts. Once you begin to stretch too far with the saw, stop, let the saw come to a complete stop without letting go and change your position to be better able to reach and finish your cut. Cutting thin sheet material with a circular saw can lead to kickback if you aren't careful. This is primarily caused by the saw binding in the cut, which happens when you over reach or otherwise pull the saw out of alignment with the cut line. It can happen suddenly and unexpectedly with a measure of violence that will make you hesitant to pick the saw up again. Hopefully no body parts were in the path of the blade and at worst you will ruin a piece of your plywood.

This is going to be difficult, but not impossible to do in a very small space. You need to clear a path around your set-up so prevent tripping over something at an inopportune moment (see above warning on kickback). Making the first cuts outside, where you have more room would be easier, then you can always break them down smaller sizes in your shop. Just be safe!

[workin for wood]

I go with a 72" excalibur sliding table and an 8' long outfeed table mounted to the tablesaw...oh..but that's just a dream..I wish I had that sliding table.

[earlinjax]

I made a "frame" out of 2 x 4's that sits on top of two saw horses. I use a circular saw and some aluminum straight edges clamped on the ply. I set the depth just a little more than the thickness of the ply and cut into the 2 by's. The down side is storing the "frame," but it works well for me.

Another idea that some people use is to lay the ply on a 4 X 8 sheet of structural foam and cut on that.

EarlinJax

[chrispuzzle]

Thanks a lot for all the detailed advice so far! It seems everybody's got their own wrinkle to add. I feel much more comfortable about handling large boards now. But do please add to the thread if you have more about cutting boards.

Gill pointed out that retailers can cut it for you but my main problem is that I don't drive, so I can't collect at the timber merchant. So I would have to find a supplier who will both cut and deliver at a reasonable price which is trickier in the UK. Believe it or not, a timber merchant just two or three miles away, almost on the same road (except for one turn at the end into mine), regards me as "not local" for deliveries! That's London for you. Mad.

Chris

[dale]

Do you have a friend that does woodworking? If so do they have a table saw.
I dont know how it would be in the UK. but many people here in my parts of Missouri do some woodworking. I had a 4X8 piece of Mahogany and dropped by the friends and he cut it up in just a min.

I have a contractor table saw but my father in law borrowed it about 3 years ago... I really need to go and pick it up now that im doing some scrolling.

bought some Baltic Birch ply wood the other day and need to cut it up.

dale

[Rivari]

I use a table saw and the eager hands of my youngsters to catch the material on the output side. With a smaller shop as you described it sounds like you definately need to do that sort of thing outdoors.

[GrayBeard Phil]

Chris:

Since you are from the city of London, and you claim little carpentry background:

The problem you will be facing is as you reach over to finish the cut on the plywood sheet, your balance is off. Add to that the problem of the wood wanting to fall down as as you cut, causing the wood to pinch the blade. The power of the saw, jig or circular, your loss of balance and thus your loss of control over the tool, plus the wood pinching the wood all add up to problems. Just how close are you to emergency medical treatment? 'nuf said!

As others have suggested, you need to make sure the wood is stable, and when the cut is finished, the wood is still stable and won't move to pinch the blade. Your balance, and thus control of the power tool, needs to be stable all through the cut also.

Only you can make the decision 'is this safe?' Just think what you are going to do, and double check under the wood. If you have a doubt, re-check and re-think. Don't barge ahead. Bill Wilson gave a lot of good ideas.

The point is you may have to sacrifice some 2 X 4 ( or whatever the metric equivalent to the imperial 2x4 is) or build some sort of low temporary table which can support the plywood sheet and you, so you are kneeling on the wood as you cut it. Just don't let the blade touch the dirt, as there will be stones.

Aside:
Plans for home made saw horse, this is in the "painter's sawhorse" style; tall, and top board is up-right. From the USA's Public TV show "The WoodWright's Show":

http://www-tc.pbs.org/wws/howto/images/e2101sawhorse.pdf?mii=1

Most english 'carpenter's style' sawhorse have the top board on it's side and is made much lower so the craftsman can use his knee as a brace to hold the lumber when cross cutting.

http://www.benchnotes.com/Wide%20top%20sawhorse/sawhorses.htm

or

http://www.handymanwire.com/articles/sawhorse.html

but thses links, the saw is still to tall to be of use as a carpenter's style since the hight should be only up to your knee.

Sorry for the long post.
Phil

[Jim Rodman]

Chrispuzzle 4'x8' Ply

Hi Chrispuzzle

All the advice given is sound no matter how you do it.
My method is just like every one else, saw hourses and 2"x4"s.

One point that I did not see mensioned was is the finish side of the
Plywood inportant (meaning a clean cut)? If so you must cut the ply
from the under side or you will get splinter cut on the good side of the plywood.
Please do not mind the spelling

Ope this will help you .

Jim form Ontario

[Mackem]

hi! chris, if you can get your hands on a couple of old pallets,lay the pallets flat and just lay your ply on top with a gap in the middle and cut down the gap. hope this helps.