Smithy lead screws/nuts

[MikeIsMachining]

Michael:


Just wanted to give you a heads up. I am going out of the country on Wednesday and will not be back until August 5th so if I don't respond to your E-mails or to the Message Thread, that's the reason. I hope you have met with success on machining the half nuts,
Peyton

Sounds good, I ordered more material and am just waiting on it to show up next this next week to get started.

 

[MikeIsMachining]

Hey Peyton,
I modeled your part and made some very basic drawings, if you can even call them that. My CAD skills are limited and I'm using Free CAD, which has it's own limitations. So the ACME threads are not modeled but the ACME bore hole size is the correct diameter for our off size lead screws. I also can't figure out the drafting mode to create drawings, so I created that PDF.

I scrapped two more parts, I misread a dimension I wrote down previously. So I had to order more material to make your parts, I'm sorry it's taking me so long. I thought I had this part figured out already but I needed to tighten up on some tolerances to make the half nut engage without binding. Here's to hoping for better luck on attempt number 6...

 

[WobblyHand]

Hey Peyton,
I modeled your part and made some very basic drawings, if you can even call them that. My CAD skills are limited and I'm using Free CAD, which has it's own limitations. So the ACME threads are not modeled but the ACME bore hole size is the correct diameter for our off size lead screws. I also can't figure out the drafting mode to create drawings, so I created that PDF.

I scrapped two more parts, I misread a dimension I wrote down previously. So I had to order more material to make your parts, I'm sorry it's taking me so long. I thought I had this part figured out already but I needed to tighten up on some tolerances to make the half nut engage without binding. Here's to hoping for better luck on attempt number 6...

One uses techdraw to generate 2D drawings from a solid model in FreeCAD. If you attach your FreeCAD model to this thread (it's an allowed attachment) I can make the drawings for you, based on your attachments above. I can then repost the file with the drawings embedded in the model if you want it. It might help you in the future.

 

[Spottswood3]

Michael: I just got back from my trip yesterday and thought I'd catch up with you. Have you had any success with making the brass half nuts for the Smithy 1220 Machine??

 

[MikeIsMachining]

Michael: I just got back from my trip yesterday and thought I'd catch up with you. Have you had any success with making the brass half nuts for the Smithy 1220 Machine??

Hey Peyton, I got more brass stock delivered on Saturday and I started working on a half nut for my machine last night. My plan was to get a working part for my machine before the JB weld lets go on my patch job. I’ll get that part installed on my machine then get working on your two parts.

Now that I have made a few attempts and reviewed all the dimensions I think that this next round of parts will work well, I’m optimistic at least. It’s been a good project to hone my skills for sure. Hopefully I’ll be done with your parts by end of this upcoming weekend.

 

[MikeIsMachining]

It looks like Smithy may be making the machines again, and that they've only dropped them temporarily because the Chinese shop they were having parts made in had covid problems. That said, there's any interpretation of how permanent "temporary" might be. Also, Smithy is used to paying Chinese prices for these parts, so I'd be cautions about winning a bid for them.

Mikels, if you have a working part, you did better than I did. If you can made the CAD or technical drawing file available, or even offer it for sale, I'd be interested.

I thought I posted the CAD file here but it looks like the attachment didn’t come through. I’m on my phone but when I get back to my computer I’ll repost the files again.

I’ll give you the files no charge, the spirit of the forum is to help and educate others. If you want me to make you a part then I would charge to cover materials, tools and time. Do you need a half nut for the 1220 XL or LTD?

 

[Spottswood3]

Thanks Michael

 

[MikeIsMachining]

Ok let's try attaching files again. Here are the FreeCAD files and the "drawings" if you can call them that, saved as the PDF. I just took a bunch of snips and put it together in a PowerPoint saved as a PDF. It works for my purposes, I'll have to learn to make drawings within FreeCAD. I didn't model the threads, the hole threading tool uses standard hole and thread sizes. I couldn't for the life of me figure out how to make an ACME profile at the odd diameter that these lead screws are. The hole size is correct to form threads for the lead screw diameter.

 

[MikeIsMachining]

Thanks Michael

Hey Peyton, I've pretty much finished making your parts. I just need to de-burr the threads with a small hand file, a bit time consuming but nothing I can't finish up this week. I'd like to get them shipped out to you, I'll send you payment info in a message. I highly recommend you test fit these and not test them under power to prevent damage to your machine. The first few of these I made I have had difficulties getting the leading edge of the threads worn in and de-burred so they don't bind up. If they don't work for some reason let me know and I'll make it right.

 

[Spottswood3]

Thanks Michael: I don't have your E-mail address but mine is spottswood3@gmail.com. I don't use PayPal because of an issue I had with them in the past, but I can mail you a check or give a credit card if you prefer. With all the issues you ran into, I think you may want me to charge a bit more than what you first quoted, so please let me know and I will get a check out to you immediately.