Wood type for letterpress printing

[Atrain314]

First time post

Intermediate CNC user

Shopbot

I need to create a series of wood type for letterpress printing

Dimensions: H x W x D 4" x 1.75" x .75"

Material: Hard Maple

What kind of roughing bit and finishing bit should I use for the best results?

[steve_g]

Anthony…
The only way you’ll get the crisp square corners that font has is to V-carve around it. You can use a fairly sharp angle to optimize the clearance. I think you need to try one that way and see if it prints well. I’ve made stamps that way successfully.
How big are the letters going to be?
SG

[steve_g]

Anthony…
I apologize for not reading closely… The dimensions were there all the time! Here’s a rendering of what a V-carved letter would look like… I limited the cut depth to .25 and used a 30° V-bit and an 1/8 inch flat area bit.
SG

[scottp55]

And I was putzing with it and removed the outside vector:)
1/8" clearance tool as well.
As usual, to slow for Steve:)

[steve_g]

Scott…
To print black where the sample was black, he’ll need that outside vector!
SG

[scottp55]

Yep, I was just putzing(first pdf I ever got to import successfully, by using Inkscape) and personally thought I liked it better and it would hold up better in my cluttered shop:) I thought I'd break the thin walls in short order.
Putzing for enjoyment.
What wood did you try it on? Maple? Did you try any finish at all?
How did they work with conventional stamp ink?
Thanks,
scott

[Atrain314]

Steve

Sorry for the late reply. Thank you for the information and your recommendations were very helpful. I have an Onsrud 30° V bit (37-21). Is that the same style v-bit you were using? If so..are you just creating a one tool path that includes one group of the vectors with the type (A) or are you breaking the letter up into ungrouped tool paths.
Also..what kind of tool path is the 1/8" flat area bit doing?

[Atrain314]

Thanks for the recommendations as well Scott.

The type face will be in soft maple. I will let you know when I get a clean finished letter for print

[steve_g]

Anthony…
First I created a boundary around the letter. This boundary could be anything, but if you were creating a set of movable type it would make sense to have it be the size your proportionately spaced letter will be.
Next create a V-carve toolpath of all the vectors (including the boundary) … when doing that in V-CarvePro or Aspire, you have the option of limiting the depth and whether or not to use a separate bit for the flat areas… You don’t have to use a separate flat area bit. If you’d rather let the V-bit clear it out itself rather than do a tool change, that works too, but it will likely take more routing time. If you go that route, set the v-bit tool definition for final pass step over at around 1%. If you do choose to use a flat area bit, the software will create a separate toolpath for the bit you selected.
In the attached photo, the toolpath lines are for the 1/8th in bit. As you can see, the majority of the material is being removed by the flat bit, and not much remains for the v bit… then there is also a separate toolpath for the perimeter cut on the boundary I added.
I hope this answered your question, feel free to ask for clarification if not!
SG