Marking out hexigon shapes

[Black Bear]

I am having problems marking out accurate Hexagon shapes. The photo included shows my attempt at this bit of woodworking.

I know, as I have been told, that the thickness of the pencil line will give an inaccurate shape that one tends to 'chase' thus losing the original size required.

It is very time consuming trying to bring multiple pieces to "near enough".

All suggestions, of a helpful nature, will be most appreciated.

Thanks BB

[dr4g0nfly]

BlackBear,

The one method that does not work is scribing arcs on a circle with a pair of compasses. You will always get a gap between the last two points.

I have two methods which depend upon the size of the workpiece;

1. Use a computer 'Vector' drawing package (Xara, Coral Draw etc), they have autoshapes which produce any number of sides, print the shape and Pritstick it to my wood and work from there. The limitation of this is the size of the paper I can print on, A4, so around 20cm across the flats.

2. I used to be a draftsman and still have all my old implements, including a 30°, 60°, 90° set square so I can use this working from a baseline on my wood.

[AlexS]

I'd disagree that you'll always get a gap if you scribe round a circle, but you do need care to get it right.
1. Your compass should be a springbow with screw adjustment, not the cheapo's that come in school sets.
2. The lead must be sharp. Draw the circle lightly so you don't blunt the lead.
3. Don't start from point A and mark all the way around the circle. Start from point A and mark points B, C & D. Then go back to point A and mark points F & E.

[joe greiner]

Whatever "Pritstick" is, spray adhesive and the like leave a gummy residue, which can creep during cutting, and need to be removed afterwards. It helps to scribe the line and remove the print before cutting, but a slightly more effective way, especially for odd shapes, is to print a reverse image and transfer it to the wood. Laser print or photocopy; probably not ink jet. Attach the print face down with staples or tape in the waste area. Go over it with a clothes iron set on "Linen" or hottest available. Do this when SWMBO is absent.:wink:

Cheers,
Joe

[jredburn]

G'day Y'all
there is a fee Cad program called DraftSight that makes shapes in any size of number of sides.
Regards
Joe

[Black Bear]

Thanks Chaps. I use LINUX so I will go into my package manager and see if there is a similar program for shapes.

The largest I am likely to use is 200mm across the points so A4 printout is ok.

I did go to the Plastic Factory here and ask if they could do me a set of templates ( I only use a set of 3 sizes)...Yes, they could, but the setting up of their computer and the cutting would cost me over a hundred dollars...No set quote given.

How would a plastic template go with pin holes at the points, work ?. Then one would rule a line between pin marks with a fine pencil. The template would be slightly larger than the hexagon needed to accommodate the holes.

[joe greiner]

How would a plastic template go with pin holes at the points, work ?. Then one would rule a line between pin marks with a fine pencil. The template would be slightly larger than the hexagon needed to accommodate the holes.

Should work fairly well, at least for a while. A short piece of masking tape at the neighborhood of each point will make it easier to find the pin marks. The template could have sets of holes for different shapes, preferably labelled.

A light touch is advisable. Each time you use each hole, with a self-centering scratch awl, the hole will become very slightly larger. Eventually, you'll need to make a new set of holes and block the previous set. Using a push pin (as used on cork bulletin boards) instead of a scratch awl could reduce that distress.

FWIW, I use a narrow strip of mylar drafting film with holes at various distances as a Q&D beam compass up to about 2-foot radius - push pin for the center, and holes for the pencil lead (0.5mm). Much more accurate than string.

Cheers,
Joe

[dr4g0nfly]

Two other thoughts, My wife sometimes does a bit of Quilting work and there are hexagonal templates you can buy for that, but they mak not be the size you need, however,

You mentioned asking a Plastic Factory, which reminded me that Laser Cutters like the 'Epilog (http://www.woodworkforums.com/www.epiloglaser.com)' (the expesive but easy to find on-line version) can wizz out shapes quick and easy. I bought a circular jig from another turner with one for £5 (the cost of the acrylic). You feed these things JPGs and the like which we've already covered.

So it might be worthwhile finding out if there is a small start-up company or even a school or college with one who will do what you want at reasonable cost.

[ian]

Hi BB
some good advice here about how to draft stuff accurately, but how are you cutting your shapes?

are you making a master template from ply, perspex, etc and then using a bearing guided bit to knock out multiple copies?
or are you making each hexagon individually?

[ian]

The largest I am likely to use is 200mm across the points so A4 printout is ok.

I did go to the Plastic Factory here and ask if they could do me a set of templates ( I only use a set of 3 sizes)...Yes, they could, but the setting up of their computer and the cutting would cost me over a hundred dollars...No set quote given.

How would a plastic template go with pin holes at the points, work ?. Then one would rule a line between pin marks with a fine pencil. The template would be slightly larger than the hexagon needed to accommodate the holes.this JPG is 200mm across the points, make yourself some master templates

[munruben]

If you have Microsoft Office Word, on the "Insert" tab select "shapes" and you can make a template any size you want up to A4 or larger of course depending on your printer capabilities. Just print it out and transfer it to your template material. Most photo editing software also has the capability to make shapes. I know Photo Impact does.