How can I do it without the fixture shown in this video - Driving Pulley

[Wongster]

Hello guys,

Long time no post.

I've been wanting to get back to the shop but... excuses excuses excuses...

Ok. I intend to start working on a 3D printer from scratch, with a good friend of mine. My knowledge in this is almost zero. The friend asked if I can make something like this on my lathe or mill:

3D Printer Extruder Drive Pulley

Found a youtube link which the poster used a fixed that allow free rotation of the workpiece mounted on the tool post and a tap in the lathe chuck:





For those that remember me, I'm still a newbie in everything after 2 years. Is there a way to do the same without the fixture?

Regards,
Wong

[EdK]

It's about time you resurfaced Wong.

Without looking at the video, that looks like a worm gear to me. I'll let the experts chime in though before I lead you astray.

Ed

[dallen]

you could do the same thing with a knurl roller that has a radius which would fit the groove

[DaveH]

Hi Wong, nice to see you back

The way shown in the video is the way to do it. Hold the tap in the 3 jaw chuck, and just allow the work piece to revolve on a spindle.

Something like a square bar held in the tool post with a spindle sticking up.
The square bar can have a taped hole to hold the spindle which is screwed into the taped hole.

I'll say what I did. 16x20 flat bar drilled and taped 6mm. The screw was 6mm (Hex head)so a 10mm bar (to act as the spindle) was taped 6mm was screwed on, then turned down to 8mm dia. The hole in the worm was 8mm.

The spindle part can be turned to the correct length so that when tightened it allows the pulley to freely rotate. (With a bit of oil)

Hope you can understand that.

DaveH

[Wongster]

I knew I could count on you folks for some ideas to do this.

Ed, lead me astray anyway I was learning how to play the guitar and so was away from my shop. Now I'm leading worship at my care group and also joined the bereavement support service as a worship leader for memorial services.

Dallen, DaveH,

I thought of knurling but I do not have a knurling tool as yet. The Hemingway Kit I bought remains, well, as a kit... Hope the metal pieces have not rusted...

I got what you were saying, DaveH. Almost like the fixture shown in the youtube video. Would the workpiece start climbing when the tap is introduced till it popped out of the spindle? I've no experience in this so pardon me if what i said didn't make sense.

I'll get some steel to try out later today, if I've chance to slip out of my office...

Thanks guys!

Wong

[Hawkeye]

The key is that you know what you need to do. Somehow hold your blank on the toolpost so that it can rotate freely against the tap in the spindle. Any way you can think of to do that will be the right way. It doesn't have to look like the one in the video.

[DaveH]

Hi Wong,
The work piece won't tend to "pop off" the turning of the tap pushes it down.
I have to say I wondered about it bouncing off or something which is why I used a hex head screw as the spindle (with a bush) - then it can't come off until the screw is removed.

DaveH

[TomG]

Hey Wong,

If you have a spindexer, you could hold the pulley that and the tap in the mill spindle. The spindexer should be free enough to turn on its own when driven by the tap.

Tom

[Wongster]

DaveH, I misread your description. I know what you mean now. Very doable for me.

Tom, I've a rotary table from Sherline with stepper motor mounted. Will this do? I will check if it can rotate freely. This will simplify the process.

Mike, I agree. Just that my knowledge is limited...

[TomG]

(10-29-2013, 10:26 AM)Wongster Wrote: Tom, I've a rotary table from Sherline with stepper motor mounted. Will this do? I will check if it can rotate freely. This will simplify the process.

Wong,

I doubt that a rotary table would be free enough. Maybe you could just mount it on a bolt with a couple of jam nuts to take up the end play. Then mount the bolt in the tool post of your lathe and the tap in the spindle. Use a bolt with an unthreaded shank so it doesn't chew up the bore of the gear.

Tom