answer me this

[sunnybob]

why cant I cut a straight line?

I put a layer of 20mm T&G soft wood over my 22mm flooring chipboard bench top. The wood fitted ok, but was of course ragged at the edge.
I measured back 35mm (distance from blade to guide on my makita jig saw), and clamped guide boards to keep the edge straight.

I cut with the makita, using a NEW BLADE, and resaonable force to keep it against the guide, this just the new wood, the chipboard is back out of the way, and heres what I got.....

You can see it started wandering before it had gone 50mm. Not only has it wandered, its slanted as well.
What is going on? This is softwood!

 

[blackrodd]

I'm afraid this is typical of the jigsaw, very difficult to cut to a line with or without a fence, unplug it and wiggle the blade and shaft usually loads of play, or old dull blades don't help.
They were designed for sweeps, curves and the like, some are better than others when new.
Bandsaws can be like it too, job to cut a straight line, Far more accurate with a handsaw or circular saw.
Regards Rodders

 

[AndyT]

My guess is that you had too fine a blade which choked on sawdust so stopped cutting cleanly.
Ideally for a straight cut you wouldn't use a jigsaw - a circular saw or a handsaw would be better. But a jigsaw ought to do better than that.

 

[sunnybob]

Blade was new, very big teeth, medium speed, more sideways pressure than forwards. The makita is in good condition, its not a scroll saw so the blade should be straight with the saw. Completely unable to stop the drift

After seeing this, with nothing to lose, I tried a shorter blade, made for metal, and moved very slowly, trying to recut. No deal, even the smaller stronger blade just followed the wonky cut.

Dont have a circular saw, and the bench is backed to wall, so a hand saw wont work.
Any suggestions?

 

[dzj]

Put a small bevel on the edge and leave it as is.
It's just a bench.

 

[sunnybob]

Put a small bevel on the edge and leave it as is.
It's just a bench.

you know what? for the past 50 years, thats been my answer to any wood question.
Now, when I am actually trying very hard to make my wood work cosmetic, I am failing miserably and consistantly, and I have no idea how improve it..

 

[KevM]

Setting the jigsaw's orbital/pendulum action to maximum can help to clear sawdust from the cut which in turn helps with a faster & straighter cut, the penalty can be a slightly rougher cut.

Looking on the bright side - at least your wandering was on the waste side of your mark.

K.

 

[MIGNAL]

Get rid of the silly guide. Use your eye!

 

[dzj]

Is the guide parallel to the line? (Or maybe the lens on the camera distorted the picture somewhat)

Most jigsaws are not a very precise tools.
Do you have a plunge router? If so, you could run it along the guide with small increments in depth with each pass. A mm or 2.

 

[Phil Pascoe]

Mark your wood clearly and DO NOT use a fence. You cannot correct a wandering cut with the saw against a fence.

 

[sunnybob]

my first cut was "by eye", it wasnt straight, or pretty.
The guide is exactly parallel.

I might try the router, at this stage theres nothing to lose.

 

[Roughcut]

Treat yourself to a Festool Ts55 and guide rail and everything will be so much easier. :lol:

 

[Phil Pascoe]

If you have a decent saw and a new blade, there is no reason why in 20mm softwood across the grain you shouldn't be able to take a pencil line out. It would seem to me there is something wrong with either the blade or the saw.

 

[sunnybob]

the festool coming in would be at the same time as the missus going out, for good. And, strangely, no, thats not a result! (g).

I cant find any slack in the makita, its had a pretty easy life. The blades are new, never used, although they did come from ebay. I am at a loss.
i cant afford to scrap the makita without good cause, I shall buy new blades and see what happens.

 

[Roughcut]

You're quickest get out of jail card would probably be just to use the router against a straight edge to finish off.
Job done.

 

[Phil Pascoe]

Cheap blades are probably your problem - stick to Bosch or DeWalt (no doubt there are other good ones, but these are sound).

 

[sunnybob]

Setting the jigsaw's orbital/pendulum action to maximum can help to clear sawdust from the cut which in turn helps with a faster & straighter cut, the penalty can be a slightly rougher cut.

Looking on the bright side - at least your wandering was on the waste side of your mark.

K.

you have struck something there. I've had this 6 years with very little use. I was unaware of the pendulum action adjuster.
i've just surfed you tube for an explanation. I shall check tomorrow, I have no idea what its set at.

 

[Racers]

Good quality new blade and check the sole is square to the blade!

You can get good results with a jig saw and guide or it can go horribly wrong.

Pete

 

[Fat ferret]

Jigsaws aren't for straight lines but you should get better results than that. I would use a flush cut router bit to tidy up your bench and buy some better blades for your jigsaw.

 

[bridger]

you will have to finish up the last bit at the end by hand with a chisel or such anyway, so why not use this long paring cut as an opportunity to test out your sharpening routine? paring soft wood is one of the tests for a sharp blade. it probably won't take much longer than setting up a router and still having to pare the last bit anyway.