Smithy lead screws/nuts

[Spottswood3]

Mike:

I have attached a PDF drawing of the half nut with the critical dimensions shown in decimal and to the closest inch. Please let me know if you agree with the dimensions shown. Also, let me know if you want me to go ahead and mail you a check.

Thanks,

Peyton Mathis

 

[MikeIsMachining]

No need for a deposit, I already have the material on hand. Did you get my direct message?

I’ll check out the PDF tonight and compare them with my CAD model. I’ll let you know if everything matches up right. I plan on starting your parts this weekend, hopefully I’ll be done by the end of this weekend.

 

[MikeIsMachining]

My measurements differed from yours, I edited your original document with my measurements in blue. What model machine and manufacture date do you have? Mine is a Midas 1220 LTD built 05/2011.

The part number and description Smithy provided me was C36041 NUT, HALF 10TPI, in the machine's manual the part description is incorrectly listed so it was a bit of a pain to get figured out.

 

[Spottswood3]

If you are referring to the quote, then yes did receive it, but no other e-mails that I am aware of. My e-mail address is (spottswood3@gmail.com).

I bought my machine back in 1991 I think and I am pretty sure it is a 1220XL but again, I am not at home so I can't verify that before next week. I will re-confirm my dimensions and let you know.

 

[MikeIsMachining]

Ok no problem, we can figure out the details once you are back home. Even if the dimensions changed between your machine and mine, I should be able to reproduce it based off your drawing and a few other measurements.

 

[Spottswood3]

Hi Mike:

I double checked the dimensions on my half nut against your measurements. I think the only really critical dimensions are the major diameter of the acme thread and "throat" where the half nut engagement lever engages the half nut to press it hard against the lead screw. I made a couple or more comments on the attached drawing. I am comfortable with the dimensions shown, but I would be happy to send you the old half nut that you can use to verify your dimensions. If you want me to send it, please let me know and give me your physical address so I can UPS it to you.

 

[MikeIsMachining]

I think having it in hand would make it much easier to reproduce. I’ll send you a message with my mailing address.

This would be very helpful for me to also create a CAD model for future reproduction. This appears to be a different part and if I want to reproduce these for resale I need to have a good model for future use.

Do you know Smithy’s part number for this part?

 

[Spottswood3]

Michael:

The part number I have from Smithy, which they verified is #30589 Half Nut. Here's a snippet from one of my many E-mail conversations with them.

Peyton Mathis
Mar 7, 2023, 9:37 AM EST
Any chance you have received a new supply of the #30589 half nuts ??

Peyton Mathis

DMT Support (Detroit Machine Tools)
Mar 7, 2023, 10:21 AM EST
No, I did get an ETA though, but they won't be here for 2 months!

Thanks,

Detroit Machine Tools - AutoMateCNC and Smithy
855-422-7745
170 Aprll Dr
Ann Arbor MI 48103

I'LL SEND YOU THE OLD ORIGINAL HALF NUT TOMORROW.

Thanks for your help.
Peyton Mathis

 

[MikeIsMachining]

I'm happy to help, tonight I ran into a slight road bump. I broke my lathe and it's likely because I didn't file in a relief on each thread to help with smooth engagement. I engaged the lead screw and the carriage locked up, breaking this small gear on the power feed gear train. Since I've never seen one of these parts in good condition I wasn't sure if anything like that had been part of the original design. Now that I look at the epoxy band-aid part that I made, it wore it's own reliefs at the start of the threads.

I started a new thread on the topic hoping to find someone who has made this part, below is a link. Unfortunately I can't make single point threads until I resolve this issue. I'm not sure how long it will take me to fix this, I need more tooling for sure lol. When don't you need more tooling to start a new project!

Midas 1220 LTD Broken Power Feed Shear Pin/Gear

I broke this little gear that fits inside the D gear on the power feed gear train. My carriage got bound up and locked into position when I engaged the power feed. This was likely from burrs on a new part I installed in the carriage. This essentially crashed my gear train and instead of shearing...

www.hobby-machinist.com

 

[Spottswood3]

I've been waiting and limping along with a worn out Half Nut for at least a year now, so another delay is not a deal breaker for me. I was unable to send you the old half nut today, but I will get it out Monday to you. Thanks,