straight cut with jigsaw

[tony359]

Hello all

I have a Makita jigsaw and I was trying to cut a panel of laminated chipboard as straight as possible the other day. To do so, I temporarily fixed a wooden guide on the panel so the tool would always follow it.

With my disappointment I found that the blade would not go in a straight line, it started straight and then it began deviating from the line I drew. Eventually I realised it started perpendicular to then cut to an angle. half way through the cut I removed the guide and continued by guiding the tool manually. The result was ok but not straight as I wanted.

Is this somehow expected? I've noticed that the pendulum can swivel a bit - I guess that's useful when you cut curves - but I was not expected the blade to deviate so much. And I thought that buying a Makita tool would give me better results.

Any advice on this? What did I do wrong?

Thank you!

 

[banjerbill]

A jigsaw is never going to be a precision tool. Rough "near enough" cutting only.
Track saw, table saw, band saw or even a router for what you are expecting.
Bill

 

[tony359]

Thanks! Disappointing but it's the answer I was looking for.

I do have a (Makita) circular saw and I made a DIY track some time ago. Do you think I could use it for my needs? Is there a specific blade you would recommend for my purpose?

 

[MikeG.]

The jigsaw is a building site tool, with very little use in a joinery or cabinet making context.

 

[AJB Temple]

There are some specialist rigid jigsaw blades that allegedly will do straight perpendicular cuts - I saw them on a you tube video a while ago. the reciprocation needs to be off and feed rate slow. Personally would not be my tool of choice - normally last resort.

You can try the extra wide blades eg: https://sabrecut.com/3pcs-t-shank-jigsa ... gKwB_D_BwE

And you can also get extra thick blades, which have less flex and less tendency to wander. Can't find the link. Sorry.

Finally, I find the Starrett dual cut blades can be useful as they are fairly kind on both surfaces and the opposing facing teeth seem to counteract wandering if you don't force the blade. Go slowly! I think these are pretty good. https://www.starrett.co.uk/shop/power_t ... s/dualcut/

 

[Rorschach]

Most people push too hard which causes the blade to deviate as it is only supported at the rear with no side to side support.

For straight cuts you want no pendulum action, a sharp and ideally thick blade and you need to let the blade do the work, just barely ease it forward. It takes a long time and honestly there are much better tools for the job (the cheapest circular saw for instance) but a jigsaw, even a cheap one, will cut straight if handled properly.

 

[Phil Pascoe]

If you need better accuracy use a different tool. Jigsaws are more accurate without any form of fence, as you cannot correct any wandering with the tool jammed against a fence. I use mine pretty much exclusively - kept clean, oiled and with the correct blade I don't find inaccuracy a problem, though I would use something else if I were doing a lot of sheet work. (I loathe 7 1/4" circular saws, though. )

 

[sunnybob]

I have a makita jigsaw.
Its as good as any other, once you understand the secret that nobody talks about..
Just behind the blade on the lower body is a lever, and there are three positions that it can be set to. Push the lever all the way forwards.
This turns off the pendulum motion and makes the tool almost acceptable.
Dont use a straight edge, the blade is not dead centre in the QD clamp, it will always track one side or the other.

Hand follow a line and it will be close to good. This will also help going round corners, but beware, anything over a half inch thick and the blade will flex.

As said, its a roughing out tool, you will need to finish the edges by other means. If youre a lottery winner, you can buy a Mafell jigsaw, but it might be cheaper to buy a bandsaw.

 

[Phil Pascoe]

... but beware, anything over a half inch thick and the blade will flex.

I've found they only flex badly when ripping something hard, and then about two inches thick - which of course the tool isn't meant for. I tried mine on four inch softwood cutting into and out through the side on an angle - both cuts were dead square.

 

[Trevanion]

As above, the jigsaw is a piece of equipment purely for rough cutting, you can get pretty good results from certain blades but it's still very difficult to follow a straight line so it's only as accurate as the user. I would say a regular circular saw or a track saw would be the ideal tool.

If it's melamine faced chipboard and you're doing a lot of cuts you need a blade with a triple chip ground tooth (TCG) pattern to put up with the hard melamine and stop it from chipping out on the surfaces. Ideally, you need a TCG with any chipboard regardless as it's a very abrasive material with lots of random debris in the mix like metal strands which will wreck the sharp points on an alternating top bevel (ATB) blade in no time at all. If it's wood veneered you'll get away with using an ATB blade for a while but it will blunt far quicker going through chipboard than it would regular timber.

 

[tony359]

Thanks all for all your advice.

Trevanion - and all: would this work for melamine? Did you mean Triple Chip GRIND tooth?
https://www.makitauk.com/product/b-29430.html

Sunnybob
I am aware of that level and if memory serves it stops the blade from pushing back and forth - should speed up cuts but make them less accurate as you say. Mine has been disabled since day one.

Maybe I pushed the jigsaw too much when I cut the panel. I'll so some more tests bearing in mind what you say.

My next job - if I can do it properly - is to cut a 120mm kitchen upstand so I end up with a 40mm piece. As the cut edge is going to be facing the worktop, it doesn't have to be perfect but it'll have to be good. I can try my homemade track with a TCG blade as you recommend, my only concern is the small dimension of the piece, which will make clamping it securely quite difficult.

 

[Lazurus]

Find someone local with a table saw and buy them a beer - After they have done the cutting for you.

 

[mbartlett99]

I learnt quickly ( from my mates who do yacht interiors); hack it out with the jigsaw nearish the line, fix something straight to the line and thn run a router down with a template bit. You can get pretty good results like that.

 

[Trevanion]

Trevanion - and all: would this work for melamine? Did you mean Triple Chip GRIND tooth?
https://www.makitauk.com/product/b-29430.html

Sounds like just the blade for the job!

Grind, Ground... Same thing :-"

 

[tony359]

I may have found a place where I can have them cut - in the end that blade is £40 so I'd be happy to pay that money to someone who can provide me a clean cut

Thanks for all the advice, I'll experiment a bit more with my jigsaw!

 

[Nelsun]

FWIW, you can increase your chances of a straighter (not straight) cut by pushing a jigsaw (gently) through a cut and easing back (to let the blade straighten up) and pushing forwards again. It all goes to pot when you get impatient and the blade doesn't clear enough waste and you push forward and the blade can't clear a straight path.

Or you can buy a Mafell and stand a good chance of coming out on top. A circular saw with a guide and a good blade will, as others have said, make for a generally more pleasant result

 

[W666]

Bosch have some very rigid blades called extra clean wood, or something like. Using one of them and no pendulum action allowed me to cut a shower panel dead straight, when my saw packed up once.