3D printed RS mainspring winder project for hobbyists

[Zero]

Hi guys,

I have started a project in Github to generate all the possible types of mainspring winder sizes from a single base design using a Python script.
https://github.com/vishnu350/rs-mainspring-winder

The STL files can be downloaded from the release section:
https://github.com/vishnu350/rs-mainspring-winder/releases

This project is a 3D printable "Rising Sun" watch mainspring winder for hobbyists. Mainspring winding for hobbyists has always been a problem, as most of us cannot afford the $1000 Bergeon set. Or sometimes, the appropriate size just isn't available. This forces most casual hobbyists to resort to handwinding or other similar stunts, which is not ideal.

This mainspring winder is designed using FreeCAD to be easily 3D printed with no post-processing/finishing required. It will approximately cost $5/set by most 3D print service providers (use eBay to find someone near you). The design is parameterized, allowing you to dynamically change the size/dimensions of the winder and the entire design will be recalculated accordingly. The RS mainspring winder is a pleasure to use when constructed correctly, and can wind in both clockwise and counter-clockwise directions.

I have uploaded a video describing the 3D printed RS winder parts and how to use it.

Will appreciate any help or feedback as to further improve the design, as I actually do not own a 3D printer (I pay for each print). I also do not know the complete range of sizes that is required to be uploaded into the release section. Also, the optimal design parameters may still not be perfect, but it seems to work pretty well for me at the moment.

Thanks.

Edited May 16, 2021 by Zero

[VWatchie]

Very interesting. Thanks for sharing!

[Sjk4x4]

I like your Staple - tab solution!

Now a person can buy a 1000+ winder set or a $300 printer and have their own.(Or order from a printing shop for less)

[Zero]

The size I printed and tested with was for a 10.5mm mainspring diameter. I have no idea how the winder looks like for other sizes, but they looked OK on screen. Let me know if you test it out.

If you want to customize the winder, just measure the your mainspring/barrel dimensions with a caliper. Change these values in the parameter spreadsheet inside the rs-winder.FCStd file accordingly. Then you can export the STL files for 3D printing.

For printing, I use the service from these guys as they are nearby me: http://www.siegeadvancedmanufacturing.com

[Zero]

5 hours ago, Sjk4x4 said:

I like your Staple - tab solution!

Now a person can buy a 1000+ winder set or a $300 printer and have their own.(Or order from a printing shop for less)

Yeah, the staple pin is an everyday item accessible to everyone. It works in both winding directions. It seems to be able to withstand the winding force, even after multiple uses. If it warps or breaks, it is easy to replace.

[bklake]

I'm going to print one and try it. 

[Zero]

17 hours ago, bklake said:

I'm going to print one and try it. 

Nice . Let us know if you tweak the parameters or did anything else to improve it. I can include it in the next release if it works well and is applicable to the majority of future users.

Some parameters I just arbitrarily chose, such as are the spring diameter shrink %, the barrel opening width, and the width/heights of the winder body, etc. I'm sure it can be optimized further, but I don't have a printer to keep testing them out. So the values i chose may seem pessimistic, due to my limited capacity for R&D.

[aac58]

I'll also try your design. I don't have a 3D printer either, but I've contacted with someone that is printing the 4 pieces for me, and he will send them to me by mail.

Not having the tool yet, I don't fully understand how I should shape the anchor with the stapler pin, it's not clear on the video. I hope I'll figure it out when I have the tool with me.

Also I hope it's not a huge problem to have a barrel bowl a bit bigger than the watch barrel outer diameter and a housing barrel a bit smaller than the inner diameter. I'm talking of one or two tenths of a mm.

[Zero]

One of the main issues I faced, is if the plunger doesn't snugly fit inside the housing barrel, it wont be able to plunge correctly. The mainspring tail would get caught between the gap while plunging.

What I did was, I would always print multiple plungers and hope one of them would fit snugly. But this is not a good solution for everyone. Lubricating the mainspring and barrel helps a lot, but is still not a solid solution.

So I had a good think about it, and added three 'teeth' to the plunger. Low and behold all of my prints work regardless of how snug the plunger fits! Please print the latest version with this change (release v0.5 and above).

[Zero]

15 hours ago, aac58 said:

Not having the tool yet, I don't fully understand how I should shape the anchor with the stapler pin, it's not clear on the video. I hope I'll figure it out when I have the tool with me.

Also I hope it's not a huge problem to have a barrel bowl a bit bigger than the watch barrel outer diameter and a housing barrel a bit smaller than the inner diameter. I'm talking of one or two tenths of a mm.

I just used a wire cutter or pliers, and kept trimming the stapler pin until i got the size I wanted. It should fit roughly like how you see it in the video. If you get it right it will keep working without breaking.

The bowl size is OK if you choose to print a bigger one. You can use also use Rodico to help center it if it is too big. If you send me your dimensions, Ill try to include it in the next release. I'm still figuring out how to bundle all the different sizes in a neat way.

Edited May 21, 2021 by Zero
typo

[xyzzy]

I wonder if the bowl could be done away with?  Put a raised ring on the winder, slightly (approx barrel wall width) outside the recess where the spring sits, which is designed to have the top of the mainspring barrel fit inside it.  That will center the barrel when the spring is pushed it.  It'll be a bit easier to see what's happening too I think.

It only needs to be about half the barrel height, so that the teeth on the barrel no longer need to be accounted for.  Then put a matching groove on the winding portion.

[Zero]

That's a good suggestion. May need to think on it a little more. I didn't try your way because the width of the barrel wall was inconsistent across different manufacturers (although with the same mainspring diameter) . I did try variations of it though, by making a little ring on the inside, but it failed. These were my findings:

1. The ring width/height was too small for the average 3D printer to properly print. It didn't turn out well.
2. I tried reducing the inner mainspring barrel diameter so that this ring could be bigger. However this stresses the mainspring when winding, causing the tail to eventually break from fatigue. So that was just bad.
3. I tried another idea variation where I made the bowl recess on the bottom of the winder base, but it felt uncomfortable on my fingers when winding.
4. I tried putting the mainspring barrel into the winder base arbor for centering, but the arbor hole on the mainspring barrel usually smaller that the arbor itself, so wont fit.

So I gave up and just designed the bowl as it was the most accessible solution and would work for everyone, even with lower end 3D printers. Also, it cost me less than a dollar to print per piece. It does work very well, I haven't failed the plunging step even once with the latest prototype. It gives a satisfying 'click' when the mainspring pops in.

Also, I find the bowl very useful for disassembly/reassembly service, it kinda works as a staking tool thanks to the arbor recess hole. You can use it to pop the barrel cover safely back on as well. And it stays put when you do the wall lubrication, or if you choose to lube the spring after winding.

[bklake]

3D printer is acting up.  I need a new hot end.  I won't be able to print until I get new parts installed.  It looks like the design is evolving so this is working out in my favor. 

[Fred]

I printed it with PLA+ and it worked, I tried 4 times and it works as in the video, thank you for designing and sharing this.

Forget about hand winding mainsprings

Edited May 27, 2021 by Fred

[Zero]

6 hours ago, Fred said:

I printed it with PLA+ and it worked, I tried 4 times and it works as in the video, thank you for designing and sharing this.

Forget about hand winding mainsprings

Nice! You got it to work on PLA+. Bye bye handwinding. No more losing bits of skin on your fingers!

I'm curious to know more.
- Were you able to use the existing STL files, or did you customize the params and regenerate?
- What do you think of the clearance/fit for the mating parts?
- Did the diameter markings on top turn out well for your print?

[Fred]

Hi, yes I used the existing STL files.

I think it’s good, it works well but was wondering if you could improve the winding base and make it modular so you can print multiple rod with different little holes and place a pin as the hook so can place it just where you want it, I’ll try to design something like that but here’s a really bad sketch of the idea. 
the diameter markings didn’t turn out well because I printed it upside down because of stringing issues, also I’m using masking tape as the printing surface but you can still tell the numbers. 
I’m attaching some pics.

thanks for sharing again and if you want me to print anything let me know.

 

 

Edited May 28, 2021 by Fred

[Zero]

5 hours ago, Fred said:

I think it’s good, it works well but was wondering if you could improve the winding base and make it modular so you can print multiple rod with different little holes and place a pin as the hook so can place it just where you want it, I’ll try to design something like that but here’s a really bad sketch of the idea.

A modular arbor pillar hole? I think that sounds like good idea to further improve the design. That way if users break the arbor pillar thingy, they can just replace it. However, I had trouble printing arbor pillars that were smaller than 2mm diameter, because it always came broken in the mail . Maybe a better solution would be to find a way to securely slot in a steel nail from the bottom, if we can find something of the right size?

Another thought is, since the arbor pillar hole would be quite close to the anchor hole, would both holes print correctly?

6 hours ago, Fred said:

the diameter markings didn’t turn out well because I printed it upside down because of stringing issues, also I’m using masking tape as the printing surface but you can still tell the numbers.

Hmm. I was never able to get it to print right either. Oh well, it is just text. We'll figure it out eventually

6 hours ago, Fred said:

thanks for sharing again and if you want me to print anything let me know.

You're welcome! I had something that worked for me for a while now, and I thought to myself that it would be very selfish if I didn't share, as I am aware of others struggling with this problem as well.

[aac58]

On 5/21/2021 at 6:04 AM, Zero said:

I just used a wire cutter or pliers, and kept trimming the stapler pin until i got the size I wanted. It should fit roughly like how you see it in the video. If you get it right it will keep working without breaking.

The bowl size is OK if you choose to print a bigger one. You can use also use Rodico to help center it if it is too big. If you send me your dimensions, Ill try to include it in the next release. I'm still figuring out how to bundle all the different sizes in a neat way.

Hi there Zero! 

After a lot of problems with the courrier I got the first set of pieces to play with, I was very excited, but the joy lasted only two tries 

I've tried to cut the stapler to the best of my understanding. Then I made a first try and although the spring seemed to slip sometimes inside the housing, I managed to get all of it into the tool, even the bridle that was a bit tougher. However, when trying to take the winderbase off, the spring wanted to come with it instead of staying in the housing, so it didn't work this forst time.

I thought that maybe the problem was that the stapler was a bit too long, so I cut it a bit smaller. I tried to load the spring again into the housing, this time I could not get the bridle into it. When I took the base off, I saw that the rod had broken. I probably did something wrong. Any advise you can share is very welcome.

EDIT: Forgot to mention that when I received the pieces, the rod on the base couldn't get into the hole of the plunger. I sanded it in the middle (not in the zone that is now broken) until it could get inside the hole with no apparent friction, but maybe I should have sanded it a bit more (or a bit less, who knows) Next time I think I will try to look for a way to broaden the hole instead.

Unfortunately I only ordered one winder base, so I will need to order it again, and that will take some time.

Anyway, thank you very much for sharing this design, I'm sure I'll get it working soon!

 

Edited June 9, 2021 by aac58

[aac58]

18 hours ago, aac58 said:

I saw that the rod had broken

Alright, today I've done a bit of brico. After sanding the remains of the winder base arbour, I've replaced the broken arbour using a pin vise and a 2 mm drill bit and a 2 mm metal rod.

I tried again with a bad shaped Seiko 70xx spring I'm using for testing. For me it's really difficult to insert the staple into the spring hole. Or more specifically, I cannot, as there's no room for the staple between the arbour and the spring, and I think I deformed the spring even more. However, after trying afew times, I managed to close the base with the barrel housing/plunger set. The staple wasn't into the hole, but it was making enough friction to wind the spring into the housing.

This time, to take the base off of the housing I used my tweezers to prevent the spring to come off too, mostly the same way I've seen others doing with the real winders.

Tranferring the spring to the watch barrel was a bit of try and pray. I recon that the barrel bowl is a bit too big for the barrel. I used the 11.8 barrel bowl, but in the printed thing I measure about 12.2 mm. I guess the 3D printers (or the printer used by the printing service I used) are not accurate enough, so I should have ordered a wider set of housings.

Nevertheless, the second attempt was successful (in the first the spring didn't get into the barrel).

I have to practice some more, and order more barrel housings, plungers and barrel bowls sizes, but if I get the hang of it it's going to be a great tool.

I like the metal arbour, I think I'll print a base with a 2mm hole instead of the original arbour. Maybe I should look for a thinner metal rod to allow for more room between it and the spring, so the staple can get into the spring hole.

Edited June 10, 2021 by aac58

[Zero]

Hi @aac58, nice work with the metal rod fix!

On 6/10/2021 at 1:56 AM, aac58 said:

However, when trying to take the winderbase off, the spring wanted to come with it instead of staying in the housing, so it didn't work this forst time.

When you finish unwinding, you should unwind just a little bit more and the staple will just unlatch itself and just come off. I think I forgot to mention this part in the video.

 

On 6/10/2021 at 1:56 AM, aac58 said:

When I took the base off, I saw that the rod had broken. I probably did something wrong. Any advise you can share is very welcome.

Most likely the winding stress has destroyed it, looks like your print service provider's plastic material may not be too good, unfortunately. Personally I did not have this issue even on bigger springs, I only broke it when I dropped them  Maybe other members here can comment on using stronger materials.

 

On 6/10/2021 at 1:56 AM, aac58 said:

Forgot to mention that when I received the pieces, the rod on the base couldn't get into the hole of the plunger.

Thanks for mentioning this. I also seem to have this problem with the plunger (sometimes). I will add a little bit more fit clearance to solve this problem, in the next release.

 

6 hours ago, aac58 said:

The staple wasn't into the hole, but it was making enough friction to wind the spring into the housing.

Actually for smaller springs, this seems to work for me as well. However, I think it is best to get the staple into the hole. What I do is just use an Arkansas stone to file the staple until it gets small enough to enter the hole (if your staple is too big).

 

6 hours ago, aac58 said:

I like the metal arbour, I think I'll print a base with a 2mm hole instead of the original arbour. Maybe I should look for a thinner metal rod to allow for more room between it and the spring, so the staple can get into the spring hole.

I like this idea very much. Please share with us the metal arbour material you used. It looks like a nail? I was thinking maybe use springbars 

I can design a separate winder base with an arbor hole with hook holes that are side by side (close to each other) based on your suggestions.

[aac58]

3 hours ago, Zero said:

Please share with us the metal arbour material you used

I bought it in a hobby shop. The tag says "2 mm x 1 m steel rod". BTW it was very hard to cut.

I have tested your tool some more times and I'm under the impression that the last turns of the spring (those with the smaller diameter) are affected by the compression. I say that because when I get the spring out of the barrel the last few turns are now closer to each other than before. The spring I'm using is in bad condition, I'll use a better (but still bad) one in the next tests. I'll try to post some photos tomorrow to show you what I mean.

Edited June 10, 2021 by aac58

[toptime810]

Brilliant, thanks

[Zero]

17 hours ago, aac58 said:

I have tested your tool some more times and I'm under the impression that the last turns of the spring (those with the smaller diameter) are affected by the compression. I say that because when I get the spring out of the barrel the last few turns are now closer to each other than before. The spring I'm using is in bad condition, I'll use a better (but still bad) one in the next tests. I'll try to post some photos tomorrow to show you what I mean.

This is expected as the arbor (2mm) is smaller than the actual arbor (~3mm), so the innermost portion of the spring compresses a little bit more. It becomes more obvious because we keep winding it again and again for practice. It seems to return to its original shape when you put it back into the movement barrel with its original arbor and wind it up normally. I also practice on bad springs so its hard to tell.

But I would like to solve this issue properly by providing winder bases ranging from 1mm to 3mm holes for a metal arbor, so we can all make it look like yours.

The question is, where do we find this metal arbor? Does the hobby shop sell with different diameters, eg. 2.5mm? Hmm... maybe try to use springbars.

[aac58]

15 hours ago, Zero said:

The question is, where do we find this metal arbor? Does the hobby shop sell with different diameters, eg. 2.5mm? Hmm... maybe try to use springbars.

They have 3mm rods too but no 2.5, but I think you can use anything with the appropriate diameter as nails.

But, with a bigger diameter, perhaps the spring will be tighter to the arbour and it will be harder to extract from the base and keep it into the housing?

Edited June 12, 2021 by aac58

[Imparatus]

This is quite and interesting project, and welcome in that I don't have a winder and can't see spending tons at this (beginning) point in my hobby horology. I DO have a Prusa i3 MK2S and a Creality 3 Pro. I'll have a look at GitHub for the STL files, and print from PLA and PETG, and let you know how it works out. I would also be interested in the design with the metal arbor, if we can source some good rods (or springbars?). I'm working on practice movements at present, the Seagull 6498 and 2824....what size would I print for those?

Imp