29k15 shuttle gear remanufacturing

[Constabulary]

The World was waiting for someone like you    

[29k15engine]

Thanks for that, i have a book on gears and gear construction, i believe the gears these days are not constructed like this anymore, indeed in the gearbox of the 29k the gear profile evolved with different tooth profiles for the 3 gear used in production.

For this reason, i decided to start modelling the gears from actual measurements of a good rack and pinion gear. This way it won't get bogged down by calculation that if slightly wrong will not product the right profile.

I can get these 3d printed in plastic and then cut in steel by a friend. But only when they fit and work.

[Wizcrafts]

2 hours ago, 29k15engine said:

Thanks for that, i have a book on gears and gear construction, i believe the gears these days are not constructed like this anymore, indeed in the gearbox of the 29k the gear profile evolved with different tooth profiles for the 3 gear used in production.

For this reason, i decided to start modelling the gears from actual measurements of a good rack and pinion gear. This way it won't get bogged down by calculation that if slightly wrong will not product the right profile.

I can get these 3d printed in plastic and then cut in steel by a friend. But only when they fit and work.

Once you finalize the 3D coordinates and create a functional part, please start a topic about it in our 3d printers and lasers sub-forum. You can even upload a file for others to use.

[29k15engine]

Going to get the fit right with lots of testing, then hopefully will have an STL file for people to try.

 

The straight forward job would be to provide matching gears and racks.

However the harder but more rewarding job will be to provide parts that can be used with genuine singer rack or singer gears therefore being equal in fit to OEM, thats the bit that will take a little time.

 

[29k15engine]

These prototypes will be the first time i can look how the parts work in reality

 

 

 

[DonInReno]

On 6/28/2021 at 2:15 AM, 29k15engine said:

 

 

 

 

Good job on your progress!    Your measurements show a pressure angle of 9.2 degrees, while many/most older gears were 14.5 degree and most gears used today are 20 degree.      Obviously non of the readily available involute-profile gear cutter tooling would be of any use - probably why it’s rare to find anyone who has done this.

 I find the tooth profile on the rack interesting - involute-profile racks have straight sides where the pinion actually makes contact, where the slight curve on the upper portion of the tooth shows these are pretty unique compared to most older gears profiles.

I’m wondering out loud if this is a cycloidal-profile style of gear such as was used in clockmaking.   On the following page it mentions that on pinions with few teeth the involute-profile becomes difficult to manufacture, and cycloidal makes more sense.     https://www.csparks.com/watchmaking/CycloidalGears/index.jxl

Looking forward to seeing progress!
 

 

[29k15engine]

Hi Don, feel free to think out loud, having modelled the gear as well I have tweaked both to do the 3d print, here are the latest drawings. I got the gear and rack to mesh with 0.001mm and no interference on full rotation with all 3 gears in correct position, so we will see when my friend pops round with the prints.

In my book it talks about lantern gears which were very round. My final drawings are not as round so we will see how they actaully mesh.

 

Edited June 29, 2021 by 29k15engine

[29k15engine]

Just found from a supplier I can get parts

8608 Following Pinion for both 29k1 but also following pinions for 29k15 and the like.

8599 Small rack

plus

8600 long rack!! which I may be able to be modified to fit a 29k15 with an adjustable rack rod.

These are all new parts.

Will keep you informed on these as it is another direction to get these parts working the older machines.

Here is a picture from the supplier of part 8600 in stock.

 

[Wizcrafts]

Awesome find!

[29k15engine]

Ok so my pal dropped of an evelioe with the parts he made on his new 3d printer.

I was hoping for the best but like all things engineering prepared for the worst... however they fit!! Like a glove

I need to tweak the end of the gear tooths a little but first fit is good. As the tooth end is a little too accurate they need a micron or 2 more clearance.

Have a look, comments and critique welcome.

Edited June 29, 2021 by 29k15engine