Tapered Round Legs with a simple 4th axis

[Jerome Stanek]

Yes, the devil is in the details. I waited to upgrade from 10x to 11x for awhile but I suspect I'll go to 12 if there's something there that interests me. Do note that there is a little increase in the upgrade cost going forward, but my understanding is that for a short time, folks upgrading right away will get the opportunity to upgrade for the previous upgrade price. For Aspire, that's $400 vs $450. So as soon as the details of what's new come out, consider them thoroughly so that if you do choose to go to v12, you can do it during that short window where the previous upgrade price will prevail. They are doing this to insure that long time customers who have kept up don't have a disadvantage compared to people who recently upgraded to v11.55 and get the V12 gratis. (This information is from a thread and company post in the Vectric forum)

I'm still running Aspire 8.5 If I need a new feature I will upgrade then. I run it On an Acorn controller running but not the lastest version of thier software. I found the newer version didn't like my setup

[Alex Zeller]

John, how did you come up with the g-code to make the leg? I'm close to finishing the rotary I had posted ideas on making. Once it's done I'll create a thread showing what i did in case you are interested. Since the rotary isn't controlled by the CNC controller what bit did you use and what did you set the feed and speed rates at?

My plan was to (I use Fusion 360 at the moment) create a 1/4" thick board with the profile I want. I was going to use a 1/4" downcut bit to do the work. This way the G-code wouldn't move the Y axis. I would manually set the speed of the rotary. The speed would need to be slow enough so the rotary could make a full revolution while removing all the wood. Too slow will take too much time and have too light of a chip load on the bit. Too fast and it's not going to remove all of the wood. It'll change depending on the diameter of the wood as well. If it's a tapered leg that's a 4x4 going down to 2" there's obviously more wood to remove at the 4" end than the 2".

[John TenEyck]

Hi Alex. I didn't have enough Z axis height to put the bit above the centerline of the leg, so I had to work from the side. My milling path was a tapered box on X and Y, the taper being the same as what I wanted on the leg. I used a pocket toolpath, and that allowed me to use the stepover feature, which worked well with the high rpm I used on the 4th axis.

I think you're going to need a toolpath strategy that machines in steps. Trying to remove 1" of material in one pass seems far too aggressive, no matter how slowly X moves.

John

[Carl Beckett]

I think you're going to need a toolpath strategy that machines in steps. Trying to remove 1" of material in one pass seems far too aggressive, no matter how slowly X moves.

John

One way of doing this is to create the finished profile offset from a zero plane. Zero on the centerline of the axis of rotation.

Then the Vcarve file use 'offset' to create a number of passes - each one offset a distance from the prior (say, .15") - which defines depth of cut. Trim these at some outer limit. When you create the toolpath, group them all sequentially to create a series of passes, each one an increment closer to the final profile.

[John TenEyck]

That makes perfect sense, Carl. But what toolpath strategy do you use to create a taper, for example, when the bit is centered above the centerline?

John

[Alex Zeller]

My plan is to try and do this.
top.jpgside.jpg
I'm just going to remove the white section inside the dashed lines. I'll move the spindle slowly and set the code multiple depths using .2" (using a 1/4" upcut endmill) as a step size. The rotary will be spinning at a speed to be determined by trial and error. The G code will think it's just very slowly making a cut on the end of a long but very narrow board.

[Carl Beckett]

My plan is to try and do this.
top.jpgside.jpg
I'm just going to remove the white section inside the dashed lines. I'll move the spindle slowly and set the code multiple depths using .2" (using a 1/4" upcut endmill) as a step size. The rotary will be spinning at a speed to be determined by trial and error. The G code will think it's just very slowly making a cut on the end of a long but very narrow board.

That is what I was imagining - and can take multiple passes to get to the final profile? (I may be missing something)

https://www.shopbottools.com/ShopBot...xerasLathe.pdf

[Carl Beckett]

That makes perfect sense, Carl. But what toolpath strategy do you use to create a taper, for example, when the bit is centered above the centerline?

John

I thought in your case John you didnt have the z height to work off centerline - but if you rotated the thinking 90 your side cut could be referenced to centerline along the 'y' instead of 'z'?

I am likely missing something.