hey there

need some advice with cutting MDF
i have a cheapo jigsaw, and i want to cut as straight as possible
i use a metal ruler for guide held to the MDF by g clamps and proper cutting blade
when i start cutting it goes straight, then it goes off track
first i thought the metal ruler had moved but i look again the i see the jigsaw itself is going straight but the blade is flexing to one side
why is this???
am i cutting it at the wrong speed?
would buying a circular saw cut much straighter?

thanx

A circular saw would be much straighter, but have you tried moving the jigsaw slower so you're not putting much forward pressure on the blade?

no i actually havent tried it at lower speed
i tried it with a guide 2 times and the blade flexed both time so i gave up
ended up just cutting without the guide, it was straighter but not straight enough to glue together

i mite play around with it few more times as im not really cool with these woodwork stuff
if not i'll just get a circular saw, it looks so much easier to cut straight

Go slow with the jigsaw. But not too slow as to burn the MDF either
Circular Saw would be ideal, but yeah, see how you go with round 2 jigsaw/guides/lower speed.

I've found if you try to push the saw too fast, it'll put too much pressure on the blade and it tends to bend in either direction, but if I slow down, it cuts straight up and down without any angle.

Jigsaw blades subject to flex only when under excessive pressures or rapid movement (trying to cut fast). Don't forget, they are how thin?

I'm a carpenter and I am very familiar with jigsaws straying from the line and I have never had success in overcoming the problem. I think they cut straight until the blade is a bit blunt and they go blunt enough after just a few cuts so I use my Dad's $25,000 panel saw in his shed (Ha Ha)

But sometimes I have to get something done on site and what I do is use a circular saw with the base lowered down to minimise chipping, then finish it off with a trimmer or router using my 1200mm level clamped to the wood for a guide. You can get routers or trimmers pretty cheap these days but be warned, they are very dangerous littles critters.

You can also use a buzzer (another very dangerous critter) or even a hand plane (with a nice sharp blade) to level-off the bumps but you really want the cut to be square as well as straight. (thats why I use the trimmer - with a quarter inch straight bit)

Hope that is of some help


Doug

If you were here in VIC, I'd say bring it past my factory (cabinetmaker) Mmmm... panelsaw

in a different direction how do u folks normally go about cutting your speaker holes. I tried making speaker mounts yesterday and lets just say my cutting isntthe greatest anything should be better

router is the goods.
cutting with a jigsaw is fine as well.
i usually use a jigsaw but for when i'm making pods i use a router for a more exact cut around the outside.

I think using a router to cut circles is a bit over the top cos after all you don't see it and it doesn't have to seal. It also takes a bit more to set up as well

To cut circles with a jigsaw you can get special blades. They are narrower (obviously a wider blade doesn't want to go around corners!) Don't get too ambitious, take your time and take a deep breath if it gets too frustrating - anyway thats what I have to do I get too impatient

good way to cut straight not that i do it as i use the good old jogsaw.
but a table saw is a good idea, also if angles are needed easy to use then say $50 router bits aswell. but yeah table saw i say would be best.

but yeah i use a jigsaw and sometimes rush a little but nice and slow wins the race with straight cuts. but also dont forget in the end carpet can caver all ;-)

Dont forget there are different blades for different materials, and it can make a BIG difference to cutting speed/stability.

thanx people

i'll be giving the jigsaw another go soon maybe this weekend, im building a system for a friends charade

A jigsaw isn't made for cutting straight lines. A circular saw will do the job much better, use a straight edge (preferably metal, but a good straight bit of wood will do) clamped to the board as a guide. You can make quite accurate cuts this way.

to use what you have may be all for the moment. First post mentions he used straight edges for guides... the blade was copping flex. So he was obviously moving too quick with it.

Buy some really good blades for the jigsaw.

The only brand to get is "Metabo" their blades are the bomb.

Failing that, buy a circular saw, better still get timber cut to size by a Wood Machinist such as "Mister Ply and Wood" or "DMK".

You can't beat the cut from a $50,000 table saw.

Phil

I'll agree with you on the Metabo brand, Phil.
That brand cuts MDF like butter! Awesome stuff. That and DeWalt is all I use.

Oh.. and the Altendorf Panelsaw... don't leave home without one