How to make a 1/2 cylinder?

[jonathan68]

Does anyone know how to create a .5 or .75 diameter perfect half cylinder shape? Every time I try it I make what looks to be more of a V shape. I'm stumped. I know there will be a 7 degree taper with the carving bit but I am unable to get even close to the cylinder.

Thanks,

Jonathan

[dbfletcher]

Can you post what you have tried? Im not sure what orientation you are trying to create this cylinder in.

Doug Fletcher

[jonathan68]

I need it to be .5 inches in diameter.

[hogiewan]

Do you want the cylinder above the board or into the board?

You can use the Gradient Designer software. Try a search on the forum as it has been linked before.

[swhitney]

you may have better luck cutting a dowel in half!!!

[bergerud]

Is this what you are looking for?

[swhitney]

but once it is resized to be 0.5 inch diameter, it is no longer a half cylinder......

I'm not sure it can be done... but if so, would like to know how.....

[dbfletcher]

Probably easiest to do with a program such as woflies gradient designer. If you search the forum, it is posted. Other paint program will also let you make non-linear gradients that will give you the desired effect. Then you simply make a pattern out of the image you create.

Doug Fletcher

[swhitney]

hmmmm... if the board thickness is the same as the diameter needed.... it might work

[jonathan68]

I used photoshop and created a half cylinder gradient and it came out the same. I'm not sure gradient designer would do any better. Still stumped. . . .

[dbfletcher]

Can photoshop create non-linear gradients? I thought it only did linear and radial. If you cant figure out wolfies, let me know and I'll create if for you and outline the steps.

Doug Fletcher

[jpaluck]

if need to be exact can be done with a modelling program and then brought in with the stl importer..if you want send me a pm I can do it for you..sounds very simple

[jpaluck]

Ok think I got it from your mpc..here is a cylinder 8x1x.5..hope this helps ya used moi3d

[bjbethke]

I need it to be .5 inches in diameter.

The best and fasts way would be to buy a point cutting round over bit.

You can use a grayscale pattern. You need a two sided carving, 1/2 inch stock for a full size carving, or 1/4th inch stock for half size. (One side carving)

Note add the seven extra stock to the MPC.

[jonathan68]

Thanks John, that file will work great! It looks like photoshop can't create these types of patterns? Bummer. Is Gradient Designer Windows only? Looks to be. . . .

BJB,

Where can I buy a bit like that? Do I need that for your mpc? How do you load new bits into designer anyways?

[liquidguitars]

The best and fasts way would be to buy a point cutting round over bit.

You can use a grayscale pattern. You need a two sided carving, 1/2 inch stock for a full size carving, or 1/4th inch stock for half size. (One side carving)

Note add the seven extra stock to the MPC.

bjbethke,
Nice! Job thats what i like to see using the custom router cutter, good thinking!

Here is one in 3/4 "raster"..

LG

[bjbethke]

Thanks John, that file will work great! It looks like photoshop can't create these types of patterns? Bummer. Is Gradient Designer Windows only? Looks to be. . . .

BJB,

Where can I buy a bit like that? Do I need that for your mpc? How do you load new bits into designer anyways?

http://www.woodline.com/c-321-horizontal-beading-bitspoint-cutting-roundover.aspx

It is a common style router plunge cutting bit. Woodline has them at a good price.

You should be able to get them at the Big Box Stores.

The MPC is a Grayscale PTN type, the one John posted will work.

To make the MPC with the router bit I posted. You need to draw two vector lines ½ inch apart, set the depth to .25 – the bit cuts ¼ inches on each side of the bit, that’s ¼ of your ½ inch dowel for each line.

[Kenm810]

Got here a little to Late,
but the idea is fun to tinker with. :wink:

[jpaluck]

johnathan

take a look at some of the 3d modelling programs like moi silo ac 3d..and many more...a lot are cheaper than photoshop..depending on what your looking for in pattern making

[hogiewan]

I made a cylinder in Sketchup (.75" radius x 6" length) and exported it to STL, then used STL importer and made a pattern with half