What's the best technique for perpendicular cuts through thick stock?

[Kugelfang]

What is the best way to maintain perpendicular cuts through thick card stock?

I printed out hull parts for my skipjack design and realized that cutting 1mm slots through the 2mm keel to accept the hull formers will be challenging. I foresee difficulty keeping the slot cuts perpendicular to the keel.

Any tips?

Thanks,

--jeff

[Skylane_182]

Originally Posted by Kugelfang

What is the best way to maintain perpendicular cuts through thick card stock?

I printed out hull parts for my skipjack design and realized that cutting 1mm slots through the 2mm keel to accept the hull formers will be challenging. I foresee difficulty keeping the slot cuts perpendicular to the keel.

Any tips?

Thanks,

--jeff

Great question! I'll be keeping track of this thread. I'm actually going to try something like this....




Or maybe even try some of the 3D printable table saw kits I've seen on the web. Right now I have just been using a chisel blade, #18 I think?...aligning carefully...and pushing straight down....then realigning....etc.

[Isaac]

Actually I saw what Darius has done. He created a 3D printed hull structure that you simply attach the external skins to. Perfect structure and no bulges or dents or warped hulls.

Maybe he can add to it.


No more conventional card stock frames.


Isaac

[SCEtoAUX]

Good lighting.
Sharp blade(s).
A good steel straight edge with a non-slip back.
Make multiple passes to cut through, do not try to cut all the way through in one pass.
Sharp blade(s).
Good lighting.
Did I mention good lighting and sharp blade(s)?

I have an piece of an old leather belt adhered to a piece of wood that I treat with stropping compound. I run the blade of the hobby knife along it to hone the edge. It extends the life of the blade quite a bit.

[Don Boose]

You can achieve vertical cuts through thick material with a single-edged razor blade. Carefully eyeball the blade to be sure it is vertical, then tap the reinforced edge of the blade with a small hammer (I have a small X-acto hammer with a plastic head that works great for this). Clean vertical cut. The narrow end of the slot can be cut out with a couple of jabs if a #11 blade or a very narrow chisel blade.

In the real world, I would be holding the blade with the fingers of my left hand, but I couldn't do that and snap the picture.

It is also easier to cut through thick stock with a knife blade if you run the blade through a piece of beeswax.

Don

[John Wagenseil]

Jeweler's saw with ultra fine blade (the more 0 (zeros) the smaller and more closely spaced are the teeth, the teeth should be closer together than the thickness of the cardboard) and a bench block (piece of wood with a slot or V shaped cut out to support the work piece). Basically the manual version of the powered jig saw shown earlier in this thread.
Use a true jeweler's saw and not a coping saw from a hardware store.

[airdave]

Perpendicular cuts will just require some careful cutting and paying attention.
Use a straight edge wherever possible and a narrow, pointed straight knife that you can control.
2mm card is not that thick.

Doug said it all.
Good lighting and a sharp knife.
And theres no need to cut through on the first pass (as Doug says).

Use a fresh blade...many fresh blades if necessary.

But best of all, build your "paper" model with paper.
Real boats have bulges, dents and warps.
"We don need no steenking 3D printed plasteek parts! We don wan them!"

[Thumb Dog]

Hi All,

And hi, Kugelfang. I agree with John Wagenseil when he recommends a jeweler's saw. I've included a photograph of my three German saws, and some of my jeweler's saw blades. Both are available through Rio Grande, the jeweler's tool supplier.

The depth of the saw's throat is a limiting factor...that's why I have three. One positive is that accurate, tight curves can be cut in thick card or even laminated mat board, while a drawback is that it will take some practice to become proficient with the saw. The blades are quite thin, and break easily.

In order to use a jeweler's saw correctly, you'll also need a tool called a bench pin. The attached photo shows mine, which has a sprung clamp to hold the work. It's an arthritis thing. Most bench pins are simple maple wedges that stick out from your bench to support the work. Note the removable steel holder I use for my bench pin.

Also, my Ryobi scroll saw accepts jeweler's saw blades and is great for getting a longer cut than is possible with the jeweler's saws.

Best of luck,

Score and fold,

Thumb Dog

[corneliusss]

Originally Posted by airdave

Perpendicular cuts will just require some careful cutting and paying attention.
Use a straight edge wherever possible and a narrow, pointed straight knife that you can control.
2mm card is not that thick.

Doug said it all.
Good lighting and a sharp knife.
And theres no need to cut through on the first pass (as Doug says).

Use a fresh blade...many fresh blades if necessary.

But best of all, build your "paper" model with paper.
Real boats have bulges, dents and warps.
"We don need no steenking 3D printed plasteek parts! We don wan them!"

We are doing paper modes and this is supposed to be a hobby and not mass production.
Therefore I do this too.

[Dave Pete]

I really like the bench Pin Thumb Dog showed. I will likely borrow that idea.

I have to wonder if a cutting pad with a similar spring hold down might be handy as well.