Why can't I cut worktop with jigsaw?

[rrh]

Years of DIY but first attempt at cutting a 60cm wide kitchen worktop.

My 15-year-old Bosch jigsaw seems to foul up halfway through: the blade has jumped out of its guide roller and is bending sideways. I'm using a straight edge clamped to the top of the workpiece but below the surface the blade has wandered enough to ruin the cut. And the jigsaw is protesting etc.

I use this as an excuse to buy a new Bosch gst100bce jigsaw. Lovely smooth and easy cut until about halfway through; then the same thing happens - this time with more smoke and drama, I suppose because of the higher power of the new tool (blade is smoking hot and bent to hell before I notice).

New blades, downward-cutting, pendulum off (on the new one - the old one doesn't have it), very slow steady and careful all times etc etc. No problems with chipping of worktop etc: very neat on all cuts so far. No sign of anything which would make the chipboard worktop suddenly toiugher to cut halfway in from the front edge.

I'm not stuck for cutting the basic lengths. I can use a circular saw or a handsaw and if necessary finish the edge with a power planer or router. But WHY can't I do it with a jigsaw? And - more to the point - how will I be able to cut out a 95x48cm hole for the sink if the jigsaw fails to cut properly after 30cm?

All advice gratefully received.

[Michael Mcneil]

If you have to cut the units on a concrete floor, try raising them up a little more than the travel of the blade with some 3 x 2s.

[G&M]

My only thought is crap blades. I had a similar worktop disaster (documented in another thread here) some time ago but on Andy's advice bought the same jigsaw as you and breezed through the work. However I did find the B&Q downcutters were useless whereas the ones from my local wood merchant were excellent.

[Peter Scott]

Is there any chance that the cut slot is closing up - being forced back together? This would grip the blade and give your symptoms. I can't think of any other reason for it starting when half-way across. Try wedging the cut open.

Peter Scott

[Nick L. O'Deon]

This is extremely unlikely, but it did happen to me about 10 years ago. Slowly cutting a worktop with trusty jigsaw and came to a grinding halt. Eventually found the cause ~ a 3 inch nail embedded within the worktop. Million-to-one chance but that's my luck. just my 2p Nick.

[BigWallop]

Try not to push to hard and cut to quickly with the jigsaw. Let the blade cut through by itself with just a little pressure and guidance from you. You've now had two jigsaws burn out and do the same thing, so it's broken. But it could be you that is thinking a jigsaw should be a lot faster than a normal handsaw and it isn't. A jigsaw is only a labour saving device for lazy buggers that can't pull a normal handsaw backwards and forward. It is a lot slower to cut something as thick as a worktop with a jigsaw than it is with a good handsaw.

A good workman never blames his tools, because he uses them properly from the start. So stop pushing to hard and trying to cut to quickly, and you might a tool that will last the length of the cut.

Sorry, but you sound just like my heavy handed brother. He too said that it was the jigsaw when all the time it was in to much of a hurry.

[rrh]

It's a tiled floor but the worktops are raised in the way you describe. Plenty of room underneath.

[rrh]

That's a thought. Blades are Performance Power, from B&Q. I have some pukka Bosch ones too so may try them before giving up. Thanks.

[rrh]

No, it's not this. At this stage I am only trying to cut off a thin strip which is under no tension or compression.

[rrh]

This is very good advice, for which thanks, but I really have been mega-careful and slow. This is a job for myself and I don't care how long it takes. With the new jigsaw - indeed both - I kept it very gentle. And I finished the latest cut with a handsaw which as you say was no slower. But I will try again, this time using proper Bosch blades after another poster's suggestion.

[Dave Liquorice]

Aye, moderate downward pressure to keep the saw from bouncing about but virtually none in the forward direction.

Statements like "(blade is smoking hot and bent to hell before I notice)" shows that the blade is being asked to do far more work than it is capable of and the operator is not paying sufficient attention to what the tool is telling him. Perhaps the operator doesn't know the signs of compliant from the tool?

[Lurch]

On Thu, 10 Jun 2004 19:07:39 +0100, "rrh" strung together this:

Because you haven't got the right technique. A jigsaw won't follow a straight edge across a worktop, you'll need to twist the baseplate on the way across to keep it in line. Don't force the jigsaw across, just let it cut at its own pace. And use decent blades. Also, you'll never get a perfectly vertical cut, it'll always wander slightly.

[Mark S.]

Cut my mum's sink bit with my Bosch jigsaw no problems.

Brand new blade (Bosch) and took it nice and slow, stopping to keep the blade coolish. Even changed the blade halfway round to another new one just to be sure and was pleased with the resulting hole. ;-)

Mark S.

[Bob Eager]

Google back a month or two; someone said something about this.

I believe it was to do with 'steering'; you steer not by using sideways pressure, but by attempting to rotate the saw about the axis of the blade. Sideways pressure will get the result you describe, even if very gentle.

[Andy Hall]

Sling them because they are garbage.

This is a good saw and will do a lot better with decent blades.

To be honest though, I wouldn't cut worktop end joints with a jig saw. Even with a decent one like this, the results are not going to be superlative.

For these joints it is better to go and hire a router and jig and do it that way.

THe jigsaw should be OK for the sink hole, because the lip of the sink should cover the sins - or is it undermounted?

You can also use a router to cut sink holes but it will need guide rails or a template to do it.

.andy

To email, substitute .nospam with .gl

[Ed Sirett]

The down cutting blades are IME not all that helpful as they tend to wear out very quickly indeed (even if you do all the right things). In fact IME sharp fine normal blades will up-cut the top of the laminate quite well and they work so much better. Try them out on an off cut to gain confidence.

The stroke on cutting 38mm worktop is very near the stroke length of most jigsaws so there can be issues to do with the bottom of the blade not cutting right through. The above is certainly true if you try to cut through the top rails of the unit carcass at the same time as the work top.

HTH

[kitchenman]

I use a circular saw to cut the straight edges of a sink/hob cut out, I only use the jig saw for the curves & corners.

Simply retract the guard, lower the front of the saw baseplate on to the work top, & align the blade on the line, switch on & lower the blade into the top, pressing down on the front of the baseplate

It helps to be left handed here, remember the saw wants to move back, so hold on tight.

Wood blades are useless for worktops, I use a Bosch 127 or 227D ali blade

If you are not happy with this method, DONT DO IT.

Pay some one who knows what they are doing.

[stuart noble]

Did the OP say what the work surface was made of? In solid wood you can always hit a resinous strip. Ikea beech is a sod in that respect. I always use the blade with the widest set (sold for rough cutting). This has worked fine for everything other than *really* intricate cuts

[Roger Wareham]

Are you supporting the free end of the worktop? If this is hanging loose, it will start to droop as the amount of uncut worktop reduces eventually closing up the bottom of the cut. If you're cutting off more than a few centimetres, the weight and the leverage effect will be more than enough to stop the blade.

Roger.

[Ged]

From personal experience...As soon as the blade gets the least bit blunt - after circa 30 cm+ of cutting worktop chipboard i changed it and had no problems..When i didn't change it, i had to push harder, the square cut was soon squint, there was scorching on the wood and then the blade snapped... You can almost hear the difference in cut as the tone changes a little when the blade is getting blunt

The glue in chipboard seems to blunt the blades a lot more quickly, similarly to cutting mdf etc. I also tended to use " brand " names such as bosch and B&D as opposed to B&Q Performance Pro blades..For a few quid more i wanted a clean and accurate cut.

I used a makita circular saw to cut the worktops in half etc...Brilliant!! Dead straight, no chipping