Cutting large mdf sheets

[ziggy1979]

Hi

I have to cut a large sheet of 25mm mdf down to 100mm strips (4 of them).

I have a jig saw, router and table saw (although the sheet is too big for the table saw).

For some reason, when i cut with the jigsaw and a straight edge clamped onto the sheet i seem to tilt it so that it doesnt do a straight cut. its a good jigsaw so im sure its user failure!!!

Can anyone advise on the best way to make accurate cuts. Perhaps theres a simple jig i could make that enables me to line up with the 100mm mark and make a perfectly straight and square cut?

Thanks a lot!!!!

 

[xerxes]

It's expecting too much of a jigsaw to ask it to do long, straight accurate cuts.

You could cut the strips oversize with a jigsaw and trim them to size with the router, against a guide. But that's a rather wasteful and tedious approach.

I would buy a portable circular saw and clamp a piece of straight material on the board to use as a guide. And mind the clouds of fine dust: it's a job that's best done out of doors.

Nowadays I often get the timber merchant to do this kind of cutting for me. It's cheap, accurate, and the resulting pieces are much easier to handle than a full sheet. And I don't have to breathe any of the dust.

 

[awbcm]

Jus to reinforce what xerxes stated above; circular saw with fine blade and a good quality strait edge.

Or

Get the timber supplier to do it for you.

Third option

Cut one strip slightly over size so you can plan it o the correct size you are after. Mark this TEMP this is your template to cut all the others.

Cut all the other strips a little larger taking into account the jigsaw ropey cuts.

Tack the template to the over size strips and run round with a bearing guide router cutter. This method you will get all most a planed edge and a square edge in one operation.

 

[ziggy1979]

Xerxes and awbcm thanks for your replies.

I usually get the timber yard to cut the boards to size but am currently working with scraps (albeit an 8x2 ft scrap).

For now i think i'll trim them to size with a router against a straight edge. What do you think about doing all the cuttting with a router (messy i know).

I am also thinking of buying a circular saw wihich brings a guide rail. It sits on the guide rail and u slide it along it. Are these worth the extra pennies compared to a normal circular saw?

Thanks.

 

[xerxes]

I've got a 4 foot guide rail with my Elu circular saw. I can rarely be bothered to go and find it, as it's usually quicker to clamp on a piece of straight timber that happens to be to hand. If I have to make an 8 foot cut, of course there's no other choice. I've also got several clamp on straight edges but I don't use those very often either.

I'm not sure I would spend a lot on a guide rail if I were buying now, unless I had a lot of board cutting to do.

 

[Bodgeit and scarper ltd]

Why not use the table saw? That is what I always use. Take the fence off and it will cut straight

 

[awbcm]

Why on earth would you want to spend your hard earned cash on a guide rail when you have timber boards and MDF at hand? It would be like giving your money to Mr Brown so he can flush it down the pan.

 

[Symptoms]

ziggy - go and buy a cheapo circular saw to do the job effectively - I'm SHOCKED to discover that Screwfix are doing a 185mm TCT bladed jobby for £19.99.

 

[HandyHands]

Tack the template to the over size strips and run round with a bearing guide router cutter. This method you will get all most a planed edge and a square edge in one operation.

If you're using the router from above, with the template on the top (so you can see where you're going), then you'll need one of these http://www.wealdentool.com/acatalog/Online_Catalogue_Template_Trim_279.html

 

[ziggy1979]

Thanks a lot guys. I'll put away the guide rail idea.

I've been using the router but i guess a circular saw is the way forwards. The rip fence on my (Ryobi) table saw is a few mm off square so never gives a sq cut (i.e. when i clamp it down it bends inwards a little). Thats why i dont use it, also the sheet is too big.

Also guys, im cutting some short straights and diagonals. This is jigsaw territory but for some reason my jigsaw cuts at an angle (i.e. not sqaure). I've changed the balde and thats straight and the jigsaw is set to o degrees. Its a Makita 4340 FCT and is a little over a yr old with hardly any use. The plastic splinter guard broke so i dont use that. Does anyone have any ideas what could be wrong. At first i thought it was me but i've checked 20 times and it cant be me all the time even for the smallest of cuts.

Thanks!!!

 

[Symptoms]

ziggy - don't expect a jigsaw to ever cut consistently square - the blade will always veer off square - not surprising really when it's only supported at one end. Properly guided a handheld circular saw will do most things ... go and get that cheapo one from Screwfix.

 

[ziggy1979]

SYmptons thanks ... i was actually thinkking of buying a Bosch circular saw in a deaprture from DeWalt and Makita.

I also want to get a hoover or dust extractor that i ca nconnect to the router, saw, etc. to suck up the dust that they give out esp when routing mdf. I was thinking the record power ones that screwfix does. Are these any good? Also, a friend told me that he bought a Karcher hoover and connects that to his tools and it works really well. Can someone please point me in the right direction?

Thanks again guys (and gals if there's some around these parts)

 

[Deluks]

Earlex do a wet/dry one for about £90. It's got a power take-off socket for tools.

I have an 18v cordless Bosch saw, well built and does the job. I also have a Wickes 1400w corded that's built like a tank, and with a 5 year guarantee. Well worth the £99 asking price (although sometimes they have it cheaper)

 

[chappers]

I have a makita 4340 and it cuts fine, use decent blades and don't force it let the saw do the work , With regards to guide rails I use mine all the time. Only use the short 800mm one with my festool. It cuts perfectly to the edge of the guide so i don't even bother clamping it.
Cut along the guide, line it up with the line further along and cut again, no need to have 8ft of guide to cut an 8ft sheet

 

[Symptoms]

ziggy - on the vacuum cleaner front I'm not sure you can better the Numatic tackle for the price - I got one of their NRV200 jobbies (Henry's slightly older brother) from Screwfix, maybe a year ago, and it's brilliant. Screwfix are currently knocking them out at £130 (inc Vat), Northern Tools @ £117.50 (inc), both free delivery. This one differs from the Henry because it has a 2 speed motor (high/low suck).

Also, as you are now intent on getting 'decent' hand-held circular saw make sure you get a corded one (not battery - although these are great bits of tackle for the appropriate job) and pay as much as you can afford; the brands being suggested are all good but as a DeWalt junkie I would generally always choose their tackle although I've a 20+ year old Bosch (GKS85S) 235mm 110v circular saw which has never let me down.