Lathe cross slide conversion to a ball screw

[Jon]

Congratulations tonyfoale - your Cross Slide Screw Conversion is the Homemade Tool of the Week!

This is a unique and well-explained modification, and your second Homemade Tool of the Week win in a row. Nobody has ever won three Homemade Tool of the Week awards in a row. Previous two-in-a-row winners are:

Brendon in 2015: Marking Gauge and Dovetailing Bench
mklotz in 2016: Bench Block Enhancements and Model Cement Mixer
tonyfoale in 2016: Horizontal Milling Machine and Drum Brake Grinder
rossbotics in 2017: Tilting Dividing Fixture and Dial Indicator Attachment, and again for Center Punch Guide and Deburrer
thehomeengineer in 2018: Ring Roller and Axle Stands
Stevohdee in 2018: Milling Machine Power Feed and Tool Post Grinder
Mark Presling in 2019: Demagnetizer and Quick Change Indicator Holder

Some more nice builds from this week:

Shear Tool by olderdan
Radius Turning Attachment by ttmrj
Rose Index Block by N4NV
Mill Spindle Plans by engineer steve
Mill Riser Block by tmate3
Clamp by orioncons36
Shear Tool by DIYSwede
Paint Removal Method by HandmadeCreativeChannel
Dial Indicator by machining 4 all
Spring Fuller by Philip Davies
Log Splitter Engine Replacement by IntheGroove
Gerson Hammer by IntheGroove
Drill Press Drill Bit Adaptor by HandmadeCreativeChannel
Wood Burning Stove and Heater by Mr.DK DIY
Gas Cylinder Wrench by Don42
Industrial Jointer Mobile Base by tiger carpenter


tonyfoale - we've added your tool entry to our All Homemade Tool of the Week winners post. And, you'll be receiving a $25 online gift card, in your choice of Amazon, PayPal, or bitcoin. Please PM me your current email address and gift card choice and I'll get it sent over right away.


This is your 12th Homemade Tool of the Week win! Here are all of your winning tools:

Horizontal Milling Machine by tonyfoale

tags: mill

Drum Brake Grinder by tonyfoale

tags: grinder, brake drums

Shock Absorber Dynamometer by tonyfoale

tags: suspension, measurement

Valve Holding Collet by tonyfoale

tags: valve, holder, collet

Laser Aligner by tonyfoale

tags: alignment, laser

Double Edge Fly Cutter by tonyfoale

tags: flange, fly cutter

Vertical Bandsaw by tonyfoale

tags: bandsaw

Surface Grinder by tonyfoale

tags: grinder, surface

Radius Gauge by tonyfoale

tags: gauge, radius

Motorcycle Frame Fabrication by tonyfoale

tags: motorcycle, frame

Treadmill Motor Modifications by tonyfoale

tags: safety, modification, motor

Cross Slide Screw Conversion by tonyfoale

tags: lathe, modification

[gatz]

did you get the LH screw from Aliexpress ?

[tonyfoale]

did you get the LH screw from Aliexpress ?

Yes, eventually. That purchase turned out to be a non-pleasant experience.

Firstly, I was hit for local tax and customs duty which doubled the overall price. TNT entered a price which was hiked up so the tax was more that it should have been. Since then I have heard that stuff shipped with TNT is more likely to have this problem. Of course they act as the customs agent and charge an additional fee. My thoughts did run to wondering whether this was a nice little earner for TNT.

Secondly, the screw does not appear to be of the same quality as the RH screw which I had fitted previously. The surfaces of the nut were ground much rougher and the action was not very smooth. I decided not to risk fitting it. It resides on the shelf in its shipping box.

That finally convinced me that the best solution was to motorise the fitted screw and drive it with an MPG in manual mode and have a powered mode which would maintain constant surface speed when facing (within the range of speeds of the VFD/motor combination). To that end I bought a closed loop stepper motor and tested a bread board lash up. That worked so well that i decided to fit a ball screw to the Z axis as well. Of course that has to be motorised because ball screws do not come with half nuts. You cannot easily disconnect the feed for manual. Anyway as of today I am waiting for that ball screw to arrive, it should have been here nearly 2 weeks ago. Not knowing what torque would be necessary to drive the screw under the hardest conditions I got a large closed loop NEMA34 motor. Almost certainly overkill.

When this is complete the lathe will be fitted with all the hardware and motor drivers necessary to be a CNC lathe. I do not want a CNC lathe. Every time that I want to turn a simple bush or similar I do not want to wait for a computer to boot up and nor do I want to have to write some G-code or do a drawing to make a simple part. I almost never make drawings. I have analysed what I want a lathe to do and it comes down to:
1. Simple turning and boring.
2. As 1. but with tapers.
3. Facing - preferably with near constant cutting speed.
4. External and internal threading.
5. Ball turning.

I have no need to make fancy chess pieces nor other fancy shapes.
Many people make ELS (electronic lead screw) conversions but most are Z axis only and so will only be capable of 1. and 4. above. Having motors on both Z and X axes allows for all the needs above and the control is still pretty simple. A few calculations of the computing requirements showed that the maximum pulse rate from an Arduino would be inadequate for high feeds at high spindle speeds so I have opted for an ESP32 to handle the smarts. Many times faster than an Arduino and dual core. The two cores allow the motor signals and operator input to be separated.
I have the software written and I am just waiting for the Z screw to get it done.

This started out to be a single sentence reply, but like the lathe itself it has been subject to mission creep.

[gatz]

Understand the frustration.
it's often good to put it into words to overcome that frustration.

[DIYSwede]

This started out to be a single sentence reply, but like the lathe itself it has been subject to mission creep.

Thanks, Tony for that line!
This absolutely encapsulates that feeling of mine, when finding myself in a project that already has sunk a pretty bundle,
soaked up even more man-hours and still (or just because of that) looks farther from (possible) completion than ever.
Then its high time to escalate the commitment!

Cheers
Johan

[tonyfoale]

.......... and still (or just because of that) looks farther from (possible) completion than ever.
Then its high time to escalate the commitment!

This is not far from completion, I know that ELS projects are supposed to take months or years in some cases but that will not be the case with this project. It has been a bit stop/start because of lead time on some bits but once I have everything I expect to finish it within a few days. Raising commitment is neither required nor possible.

Preparing a post for this forum on the work will probably take longer than doing it.

[DIYSwede]

Tony: My post was entirely intended to be of the "self-reflective" kind,
in no way implying you would be suffering from my particular shortcomings.

I for one, am eagerly awaiting further posts on your cross slide mods.

Cheers & keep up the good work!

Johan (assuming I really should postpone my project procrastination)

[Toolmaker51]

Johan (assuming I really should postpone my project procrastination)

Good Sir; aha; good to know more than one of us expends effort that way, postponing procrastination. Looking for some tidbit to ally this link-wise, found that procrastination not exclusively a negative trait.
Now, what was I doing?

[tonyfoale]

Tony: My post was entirely intended to be of the "self-reflective" kind,
in no way implying you would be suffering from my particular shortcomings.

I understood that, I was just having a bit of fun with it.