Lithophanes with 1/32" ball nose bits

[Eagle55]

Doing this on my phone tonight so please forgive me for not researching the forum thoroughly to see if there are those who have used a 1/32" tapered ball nose bit to cut lithophanes in 1/4" Corian. Was wondering if detail is much better and what other parameters are necessary to change and is it worth it? Like can you carve smaller lithos with good details. I have used 1/16" tapered BN for what I have done but looking for some more ability out of the machine.

Roger

[sk8nmike]

I use a 1/32" Tapered ball nose for some of my work. When to use it depends on the level of detail that the model has. The fine details get a lot clearer, but not much change on the larger areas. And the time to carve is greatly increased too. So I would say that on a piece that I really want to impress someone with I'll use the 1/32", if it's something to sell at the local flea market don't waste your time (or the machine's).

[Eagle55]

That's pretty much what I thought and wanted to hear. I have a customer that wants a smaller size litho and I knew the detail quality would be greatly reduced with the 1/16" BN bit but also have a fear of using smaller bits. I bought some 1/32" end mills one time and have yet to use them for fear of snapping them as soon as they hit the material. I'll have to venture out and give them a try. Seems like I bought 8 or 10 of them by mistake one time. Maybe I can learn how to use them before I break too many of them.

Roger

[BillK]

Hi Roger,

If you do end up using the 1/32 ball endmill you can probably use a 18% stepover with no issues to the details. Not sure if you'll remember this post http://www.cncsharktalk.com/viewtopic.php?f=4&t=1672 but its set up for the three common sizes. As you can see from the chart, you get the same surface finish with a smaller bit at a higher stepover.

[Eagle55]

Yes Bill, thanks for posting that link, not for information to go to, but rather a reminder that I had saved it in my "Knowledge Base" or training info from where you had posted it before. I went on to do a little more calculating from that same math work that you had done plus a little drafting illustration of my own and realized that if I determined that a height of .0005 is what I determined my desired finish quality was, that if I used 18% with my 1/16" bit (with step over of .0011 then I could use the 1/32" bit with a step over of 25% and achieve that same finish quality (.0005 = height) and it would produce a step of .008 and detail (on this particular photo) would be greatly increase with an increase of about 50% more time or from 2 1/4 hours to 6 3/4 hours. Now that is a substantial increase of time and not worth it for the typical or 5x7 kind of images that I have done in the past but it would let me go down in size and maintain that same quality at a 2x3 size carving which is what my customer was looking for.

I have run into a man in Ireland that specializes in porcelain work and we are trying to see if he is able to transfer a carved litho to a porcelain litho (which is actually where the history of the lithophanes originally came from. Will be interesting. I have sent him both positive and negative carvings to work from. Thanks again for bringing that excellent knowledge back to my attention. Sometimes we get focused on "what we do all the time" and forget we still have a lot of options. Haven't had a lot of time to spend on the forum lately, and miss it a lot, but still carving.

Roger

[BillK]

Congratulations Roger, you have learned well! Good luck with your project. Hope a few of you newbies got a little out of that, lol.