[Fastest1]

Thanks for sharing, good to know others are human too!

[Crevice Reamer]

Alls well that ends with only a loose quill. We've all had--or WILL have worse mistakes.

CR.

[Analias]

I haven't had much time to play with the X3 and solve the spindle control problem I have been seeing. The problem I see is a constant voltage of 11.38V DC coming out of the analog output for the motor controller on the C11g. No matter what I try setting the spindle speed to, this voltage never changes. Depending on what speed I set, the LED for pin 14 flicker appropriately for the PWM ratio. The motor controller in the X3 is fine. If I change the voltage supplying the input side of the PWM circuit, the motor speed changes appropriately.

I finally noticed that the LM2907n chip was extremely hot to the touch, even with the power to the C11g disconnected. I suspect I have a blown IC since this chip is listed as a frequency to voltage controller. Sounds like a PWM controller to me. I've ordered 10 extra from Mouser and I'll see if this fixes the problem. I may still have problem, if something else caused the LM2907n to die.

I'm looking for a schematic for the C11g (v5.4), if anyone can point me to one I would appreciate it.

As a longer view, I have decided to replace the C11g with a PMDX-126. I also purchased a PMDX-107 PWM board and an ethernet SmoothStepper. I had really good luck with this gear on my CRP-4848 and I like the extra I/O that the PMDX-126 and ESS afford. I recently picked up a used case that is larger than the original case that Kelvin used for his controller. I expect I'll also pick up the PMDX-134 motherboard for the Geckos and the heat sink that goes with them. I hope to start laying out the new electronics soon.

I'll use the gear I replace for a future CNC lathe conversion.

[Analias]

My diagnostics were correct, it was the LM2907n on the C11g. Swapped it out with a new one and the spindle started working fine.

[MRM RCModels]

Nice!

[Analias]

I have a totally newbie question. My tooling plate is drilled and tapped for 3/8-16 bolt pattern. All the holes are tapped so using dowel pins in the existing holes is not an option. I'd like to use dowel pins for locating fixtures. Do "they" make dowel pins that are partially threaded?

I was thinking of getting some 3/8-16 bolts and parting the heads off of them on the lathe. Although, I'm worried about the bolt shaft diameter tolerances and hardness for durability. Is there a better solution?

One of these days my skills will be up to threading dowels on the lathe, but not quite yet.

-Freeman

[SSN Vet]

I'm not machinist, but I've had some time setting up punch press tooling, where all the inserts were registered with dowel pins.

I don't think you can get the same acuracy with a threaded hole as you can drilling a hole and then broaching it to the exact dia needed to mate to the hardened pins. All the ones I've seen have increadibly tight fits and had to be tapped into position with brass hammers and removed with a punch.

Hopefully a 'real' machinist can chime in.... or perhaps you can pose the question to the guys who sell tooling plates.