No matter how I approach this cut my jigsaw blade bends sideways. Advice?

Submitted by fruitybix t3_10k13w2 in DIY

Apologies, Imgur is not letting me upload images tonight, words will need to do -

I'm trying to rip some recycled pine boards up the middle for a project. The boards are 1800mm (~6ft) long and 25mm (~1inch) thick. I know that any other power saw would be better but I have a Ryobi battery powered jigsaw with a stack of decent cutting blades. The jigsaw has a guide which allows you to screw in bits of wood to make it longer, which I have done.

No matter how I approach this the jigsaw blade slowly bends itself to the right as I go, eventually jumping out of its guide. I've now got several wonky cuts at each end I'll have to sand down and patch somehow and two bent jigsaw blades.

I was concerned it was the jigsaws guide being off but I've taken steps to ensure it's square and Ive also checked and rechecked that the jigsaw itself is set to 90°. I've also tried at the lowest setting and it's still wavering off.

Timber is from an old bedframe Ive been up and down the thing and removed all the screws and nails.

The jigsaw goes through thin ply, 5mm aluminium and a much softer pine board of similar thickness without issue, but I've not got anything else super long to do a long test cut with.

Any troubleshooting ideas? I can go find a makers space with a table saw but I was hoping to get this done at home.

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bobwazere t1_j5nsr9k wrote

You will struggle with a jigsaw. Buying a blade specifically for hard wood might help but a track saw or table saw are much better options.

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fruitybix OP t1_j5nt7pk wrote

Replying to bobwazere (#1,464,407)

The first blade I bent was for 50mm thick hardwood, and Ive seen a few people online succeed in long straight cuts.

but after a bit more playing around I may need to go find somewhere that will let me use their table saw. I'm thinking the entry level jigsaw I have isn't up to keeping things straight for that distance.

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caskey t1_j5ntazv wrote

Jigsaw blades are "bendy" so might not be the best tool for the job.

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opensourcefan t1_j5ntr4v wrote

If your cut is closing in on itself it may be causing the blade to drift. Try wedging the cut as you go. Also try slowing the pressure down, give it more time to cut.

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fruitybix OP t1_j5nu9jb wrote

Replying to opensourcefan (#1,464,470)

I'll try the wedging thing tomorrow, Ran out of light today.

I'm being quite gentle with the cut, letting it pull me along.

If it messes up my only other long hardwood blade tomorrow I'll go find time in a makers space.

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Tennonboy t1_j5nxnd4 wrote

Jigsaws when cutting down the grain, will naturally follow the grain your never going to get a decent cut with what is effectively the wrong tool to do the job. Circular saw is the answer

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bowenam t1_j5nzpgs wrote

Replying to fruitybix (#1,464,437)

I don't think any jigsaw would be satisfactory, entry level or top end. You would be better off using a nice sharp handsaw and wedging the cut open as you go. Circular or table saw would be better, but if you don't have those.......

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Old_timey_brain t1_j5od7eu wrote

Troubleshooting.

Flip the board over to see if it veers the same way. If so, it is not the board, and you have eliminated one possibility.

I ran into this with a band saw when the blade guide wasn't perfectly straight, but I don't know how that could happen on a jigsaw.

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Warm_Introduction_93 t1_j5oj8am wrote

Best you can do is to go very slow and let the blade do the work. Don’t push the saw. I absolutely hate jigsaws for this very reason. They are only good for cutting very thin wood. Cutting curves with a jigsaw are even worse on thick material. Bandsaw is the way to go there.

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real_b_man t1_j5oj9vo wrote

You need to understand that the "pivot point" of a jigsaw is right in front of the blade. Many people try to force the front where they want it to go, instead of stopping forward movement and moving the back end of the saw.

That being said, open ended blade tools will wander, you'll never get a band saw like cut

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mynaneisjustguy t1_j5p75s8 wrote

This is a weird one; look at the grain, is your cut following it? Also turn off the blade oscillation if it has it, and turn the speed down and go slower. If you have a good pencil line to follow you don’t even really need guides or rails, but without photos of your setup can’t tell if your rail guides are set up right. Try freehanding it down a pencil line you put on with a straightedge. A tracksaw would be ideal or a bandsaw if you know anyone. But a jigsaw is possible. It’s just the worst power tool for the job.

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bestguessautotech t1_j5paa19 wrote

If you don’t want to buy another power tool and don’t mind working for it, get a decent hand saw. It will get the job done for not too much money.

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Better_Ad4073 t1_j5pkkx6 wrote

You might be going too fast. If you’re pushing the saw faster than the blade can nibble the wood it will bend. Go slow and keep your eyes on the spot where blade cuts the pencil line. It that wood is very hard this will take a long time.

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agate_ t1_j5q77hg wrote

Jigsaw blades are designed to make curved cuts. Getting a straight cut out of one is like trying to use a hose as a straightedge, it's just the wrong tool for the job.

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fruitybix OP t1_j5wjumw wrote

Replying to mynaneisjustguy (#1,469,221)

This is spot on.

The blade is following the grain, and curving off with it.

I've forked out for a nice circular saw that's compatible with my existing battery packs which I've wanted for ages. I Also grabbed a blade that can also cut plastic and aluminium as I do a bit of work with those.

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fruitybix OP t1_j5y11xo wrote

Replying to mynaneisjustguy (#1,502,180)

Yeah I don't have power in my workspace and the landlord declined my kind offer to pay an electrician to run a line out to the standalone garages in my apartment complex.

So every power tool I own runs off battery packs, except my sander - for that I strategically drop an extension cable out of my bathroom window and down into an unused space by the side of my apartment complex then hope the neighbours don't complain.

I've been holding off buying more tools but since I'm likely to be here a while longer I forked out.

I went with this one - https://www.bunnings.com.au/ryobi-18v-one-hp-brushless-circular-saw-skin-only_p0291681

It's... Ok. Cuts angles and can do plunge cuts.

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fruitybix OP t1_j5y1vmr wrote

Heya all,

Thanks for the amazing advice and suggestions.

The blade was following whatever bit of end grain it liked best and that slight bend quickly became exaggerated.

I caved and got a circular saw, cuts are done and if I keep at it I'll have a new display cabinet over the weekend.

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mynaneisjustguy t1_j5yn1oz wrote

Replying to fruitybix (#1,502,860)

Looks decent, seems like it can run on a track also for those long straight lines. Yeah I would have to get a genny if I needed power tools, only thing I have on battery is a small drill/screwdriver combo. But I mostly use hand tools anyway or a bandsaw, I make boats and since I can’t afford my own boatyard I tend to live and work in someone else’s workshop, they tend to have to big stuff nicely set up so I just turn up with my personal edges tools etc. they are paying me for my knowledge more than anything tbh.

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