Fun with Paul Rountree's Threads gadget

[JChrisK]

I've been playing with Paul Rountree's Threads gadget (http://paulrowntree.weebly.com/gadgets.html). Works great - very strong. See photos below.

[basecircle]

Great Job. I like it. Your thread's look clean. No chatter. I bought a cutter but have not tried it yet. Did you machine the cyl on your machine. Or did you do them off line on a lathe ? what size stock were you using? It looks like you were using Red Oak on one. I have to get Going on this. Basecircle

[JChrisK]

I don't have a lathe - machined on table. Woods: Aspen (I think) and Cherry. For the Cherry used in my Part 2 post and the nuts/bolt heads, I oriented the grain parallel the X-Y plane. The Cherry did great, and the Aspen was almost as good. For the Aspen, I oriented the grain of the male part parallel to the Z axis as an experiment. I'm still not sure which is stronger.

Again, Rountree's gadget works perfectly. I tried to make it more difficult than necessary. (Obviously, I don't follow directions well.)

Some thoughts:

Material size. I wanted to maximize depth of cut/ length of tube. I estimated I could jog the bit over a blank approximately 5" in the Z axis. The bit fit, but when my ShopBot jogs to Home, it raises 1" above the blank's surface. That exceeded my machine's Z axis limit. So, I changed to a 1.5" fly cutter and milled the blank down to 3.5" or so. There's probably a workaround, but I haven't investigated yet.

Cutting cylinder/holes. After running the gadget, only one toolpath is created. I kept looking for a separate toolpath for cutting the cylinder/hole. Instead, the vector is a solid pink line/circle that shows up when selected in the 2D page in Aspire. Using that solid line, run the profile toolpath (inside for female and outside for male cuts). It works - no need to try to tweak anything yourself. Then, run the threads toolpath that shows up in the Toolpath List using the Magnate bit. Be sure to widen the in/out profile cuts to accommodate the width of the Magnate bit's side cutters.

Lack of chatter. I used a fairly long 0.5" upcut spiral bit: HTC 170-2500, CEL 3" and OAL 6". So, I went slow - I think - plunge 1", feed 1", RPM 9000.

Location on blank. Rountree's instructions state that your initial circle vector merely provides the Threads gadget with a center point -- your circle is not part of the threads calculations - it does not auto-populate anything in the gadgets form. You enter the pitch size in the gadget form. Just like he says.

Mind the gap. I have not removed the bottom portion of the Magnate bit - the part that accepts the bearing assembly. (I did remove the bearing and retaining screw.) So, I left extra room at the bottom when making the threads cut. Rountree clearly provides this warning as well.

For the "bolt," I decided to mill the heads separately, adding a pocket for the finished threaded cylinder. Then, I glued the two together.

[galerdude]

Way Cool

[dwilli9013]

Agreed very cool gadget. I can see a lot of projects spawning from this.

[basecircle]

Thank you for the step by step instructions. I will have to get going on this. Basecircle