I have been scratching my head for a few days now and I haven't a clue how to solve this one.

I need to cut a hole in my Striker bonnet for the air filter to poke through but how do I mark it?

It needs to be something like this one here.


RAW demo

Any wonderful tricks to mark it all up before I start cutting?

Cardboard and masking tape.

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Originally posted by big_wasa
Cardboard and masking tape.

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Cut a small hole and keep removing, making it bigger, and refitting. Once it actually fits over completely, mark an even distance all around and finish with one more enlargement.

[Edited on 18/5/16 by matt_claydon]

I'd start with lots of measuring... then give up on that and do as Matt says. Start small and work up.

Is this a burst of enthusiasm, post Llandow?

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Originally posted by adithorp
Is this a burst of enthusiasm, post Llandow?

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Taking the Dremmel to my own car is one thing... doing it to yours is a different matter entirely. I'm on a diet anyway.

[Edited on 18/5/16 by adithorp]

Buy a very large box of corn flakes and extra milk. Eat corn flakes.


Cut the front off the box plus 25mm of the side. L_________________ like this.


Clamp the 25mm edge to the top chassis rail a suitable set distance from the scuttle, ( scuttle to edge of box 500mm ? )


You now have a sort of hinged flap that you can offer up to the filter. Start cutting the hole, offering it up to check progress,
until it passes over the filter. Bend and curve the cardboard to shape and check it still passes over the filter.
It doesn't matter if the hole is a bit tight. You can always make a hole bigger, but not smaller. ( As Matt says. )


Un-clamp and stick it on your bonnet using the "scuttle to edge of box" (500 ? ) dimension.

Mark and cut. Trim and round edges & corners with a flap wheel.


Paul G

Thanks for all the suggestions

I have loads of cardboard (so no need to feed my family on cornflakes for every meal just yet) its just getting it to bend over the bonnet that is curving in two directions at once is difficult.....however its the best option I have. Will start cutting (card) this lunch time and see how I get on!

I am sure I have seen a write up on how to do this somewhere but I can't find it now and I just want to get on with it

You can make a pattern of a curved surface by applying multiple strips of wide masking tape over it, put some wax on it first to reduce the tack of the tape and alternate the directions you put the tape down till you have a good thickness. Take the tape "patch" all the way down over the chassis rail to give you a reference once you peel it off the bonnet. Then fit the filter and stick the tape back on the chassis rail and cut it to suit as described by 907. Then put bonnet back and mark out

Cheers

Fred W B

[Edited on 19/5/16 by Fred W B]

quote:

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Originally posted by Fred W B
You can make a pattern of a curved surface by applying multiple strips of wide masking tape over it, put some wax on it first to reduce the tack of the tape and alternate the directions you put the tape down till you have a good thickness. Take the tape "patch" all the way down over the chassis rail to give you a reference once you peel it off the bonnet. Then fit the filter and stick the tape back on the chassis rail and cut it to suit as described by 907. Then put bonnet back and mark out

Cheers

Fred W B

[Edited on 19/5/16 by Fred W B]

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Cutting the exhaust aperture in my MK Indy bonnet I started small and got bigger until I had the shape I needed - time and patience are the key to this IMHO.

You could just make a complete cardboard bonnet so you know it'll line up...


But however good a pattern you make, when it comes time to cut the real thing, make sure you cut it undersized to start with so you'll have room to make adjustments

Silly things like a different thickness of cardboard compared to the real bonnet could make several mm of difference to the size and position of the hole....

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Originally posted by mcerd1
You could just make a complete cardboard bonnet so you know it'll line up...

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