[TOTALLYRC]

Looking pretty good Michael.
If I need another lathe this looks like a quick and easy way to have a small cnc lathe.
Mike

[mhackney]

Small is relative Mike! This 10x22 is a big step up from the 7x14 I have!

Cheers,
Michael

[mhackney]

I have 3 machine projects going on in parallel:

CNCing the lathe
Redoing the control panel on my G0704 mill
Finishing up a 2'x3' router that I picked up partially completed

I'm actually getting a lot done working like this.

Made some progress on the lathe. Finishing up the bellows to protect the Z axis ballscrew and got my steeper covers mounted.

Attachment 253396

Attachment 253398

[mhackney]

Just a little more info on the bellows and mounting. I provided a link to the source for the bellows above. It is 5.5cm diameter and 110cm long. One piece is enough for both sides of the ball screw.

For the mounts, I started with 2" OD aluminum tubing with a 3/8" wall. I cut two 2-1/4" pieces. Each piece will make two mounts (you need 4 altogether). I turned the OD down to 1-7/8", chamfered the edge to help install the bellows, and added a 1/8" wide groove 1/16" deep in the middle (7/16"" back from the front edge). This groove will help secure the bellows with a zip tie or tubing clamp. You can see this in the last photo above. Then I flipped it in the lathe to turn the other end. Parting off yields two mounts. They are about 1" long each.

I drilled clearance holes for a 4-40 screw 180° apart. You will need 4-40 x 1-1/4" long screws to install them. I used the mount to layout the holes in the lathe head and the saddle. I actually removed the saddle side plate and the bearing mount plate from the head so I could drill #43 holes and tap them 4-40.

I'll post photos of the tailstock side later today, it is a bit different due to the ball nut mount on the saddle. The bellows needs to be slightly longer on the headstock side. I moved the carriage/saddle all the way to the right and stretched the bellows to fit without too much tension. Cut it between two of the metal hoops with a sharp knife. The shorter piece is perfect for the tailstock side. For now, I am using zip ties to attach the bellows (see the 1st photo above). This works fine so I may not change it.

Regards,
Michael

[mhackney]

I am struggling with figuring out how to add a quadrature encoder to the spindle of this lathe to 1) get RPM and 2) allow threading. The KFlop requires a single ended quadrature encoder. The issue is, the spindle diameter is 40mm and I can't find any commercial encoders that are large enough. Tom (Dynomotion) recommended looking at usdigital.com. I found this: US Digital | Products but it only works with 1" or 2" disks. I've googled until I'm blue in the fingers and haven't found a solution. I suppose the other option is to install an encoder on the motor shaft (3/4"D) but that will be a bit of a pain. Anyone have any (constructive!) suggestions or ideas?

[Fastest1]

A toothed belt arrangement off of the spindle itself might work. My Dyna lathe was done like that. In fact I just dug the assembly out of the extras box/es. It uses a HEDS-6310 (022 8 S).

[mhackney]

Thanks Fastest1. I saw a couple of setups that drove the encoder off the spindle. I'd like to avoid the extra complexity.

Meanwhile, I got some feedback from Tom on how KFlop uses the encoder and I think I have a workable plan now. Basically, I can cut my own encoder disk to fit the 40mm D spindle. Then use 2 optical sensors, one to read the leading edge and the other 1/4 slot width behind. I don't need an index pulse for this application. I have everything I need to put something together this weekend.

cheers,
Michael

[Fastest1]

I dont like it either, hence why it was in the "parts" box.

[lcvette]

mhackney,

I don't see the spindle mounting but you could always build a driven shaft for the encoder to ride on with a small timing belt that would do the trick and save having to get another encoder. just a thought.

The build is looking great, I hope to grab a small lather myself in the near future, i hate having to setup the G0704 to turn parts now because it means re tramming the head etc.... nice to have a dedicated lathe.. think it is in my near future!! Following with interest!!

Chris

[lcvette]

beat me to it....

[pippin88]

Don't you have to have an index pulse for threading?

[mhackney]

Yes or no depending!

With the KFlop I don't need the index pulse. Mach3 requires an index pulse though.

[bhurts]

Cnc4pc has a index pulse card for under 30 dollars. It should be a lot easier to implement than a encoder. It will still allow you to get rpm and do threading as well.

Ben

[mhackney]

I have a C4 on my G0704. However, I want to "go native" with KFlop and utilize it to its max. It turns out that fabricating a quadrature encoder to fit is not a bit deal. I'll be posting photos and the design soon. Total cost less than 10 and it uses the inputs on KFlop and will provide much higher resolution for threading.

cheers,
Michael

[wizard]

Yes or no depending!

With the KFlop I don't need the index pulse. Mach3 requires an index pulse though.

I'd like to know how they do threading without an index pulse? The only thing I can think of is that they use a counter that roll over in sync with the spindle.

[wizard]

I think deep down in your heart you know you where meant to be a CNC mechanic.

I have 3 machine projects going on in parallel:

CNCing the lathe
Redoing the control panel on my G0704 mill
Finishing up a 2'x3' router that I picked up partially completed

I'm actually getting a lot done working like this.

Made some progress on the lathe. Finishing up the bellows to protect the Z axis ballscrew and got my steeper covers

That is a lot of machinery on the flight deck. It is good to see things going well for you and your little business as I haven't check into this section of CNCzone for some time.

[SCzEngrgGroup]

I'd like to know how they do threading without an index pulse? The only thing I can think of is that they use a counter that roll over in sync with the spindle.

All that's needed is some periodic indication of where the spindle is. Mach 3 needs a single index pulse, because it isn't setup to use more pulses. But more pulses allows more accurate tracking, so a full encoder is always better. An index pulse is not required, as long as the controller knows the PPR for the encoder. KFlop uses and encoder, so will provide more accurate threads, especially under conditions where the spindle speed varies with load or over time. Mach3 can only average out speed changes, which will result in accumulated errors.

Regards,
Ray L.

[Fastest1]

I have actually disconnected my index sensor during threading and still had good results. Nobody understands that 1. Me either but it worked.

[SCzEngrgGroup]

I have actually disconnected my index sensor during threading and still had good results. Nobody understands that 1. Me either but it worked.

The technical term for that is "dumb luck". Your spindle speed just happened to be very close to what it was supposed to be.

Regards,
Ray L.

[Fastest1]

Exactly. Btw I dont count on that technique.