3D printed mid 20's AC Speedometer wheel yoke

[Hubert_25-25]

Mid 20's AC Speedometer wheel yokes are made from pot metal.  They were used in 1925 to 1927 Buick and Chevrolet speedometers and likely several other makes.  Feel free to tell me other dates or vehicles used.  This part disintegrate over time and the speedometer wheel stops functioning.  Sometimes the disintegration is minor, other times it is catastrophic and this part cannot be repaired and must be replaced.  JBweld will hold some of the better ones together for some period of time.

I have a 3D model of the part.  It was drawn by a high school student , and it is ever so close to what is needed.   There are also 2 variations of the yoke, and it would be nice to have a file for each to minimize the work required to make the 2 different style replacement parts out of one basic piece.  

Photo are of the AC speedometer used the most, and of the original parts and the 3D printed piece. 

Recently the AACA was looking for opportunities to try to infuse some 3D printed parts into our group, but I have not heard of who was selected for making parts.

What I am wondering is if anyone has access to a cad program that would be willing to make edits to this source file.   Maybe you know a student that would like to help out our hobby.  

     Thank you,     Hugh  

Edited September 12, 2019 by Hubert_25-25 (see edit history)

[Crazyfamily]

What can I do to help Hugh? I am in a few 3D printing groups and can ask for some help.  What needs to be done?

[Hubert_25-25]

William, 

       I have the part basically drawn in 3D, and I have started but not finished a drawing in how I draw stuff (Top, back and right side view).  I know, I am old school.  Maybe I need to finish the drawing that I have and get this to you along with the .ipt file that needs to be modified.  

 

Thank you for your help.     Hugh 

[Restorer32]

Why not just have it lost wax cast ?  Far less expensive and it can be made from bronze or aluminum.

[bradsan]

Hugh

 

Our speedo was rebuilt 6 years ago by either Bob's or Bill's ( can't remember now!). It came with no warranty as the pot metal disintegration process never really stops . I am definitely interested in this part. I can't tell you which of the two options we need as the speedo is assembled and I don't want to take it apart until it isn't working! Likely get one of each!

Why not just scan it and create a file to work from? Gary Ash on this forum seems to have a lot of knowledge and sources on 3D printing.

Any thoughts on doing the speedo body as well ? They are made of the same 'crummy' material and I can already see problems around the shaft input threads on ours.

 

    'Why not just have it lost wax cast ?  Far less expensive and it can be made from bronze or aluminum. '

As I recall  , the piece interlocks with the body with some pretty tight tolerances which is one of the reasons they crack when they swell.  The sample part is already distorted from the cracking and swelling so you would have to fix the dimensions before you did any casting ( I think I just answered my scanning question! Maybe scan first and then adjust the scanned drawing to fix any distortion? ) Plus, its a tiny part and you'd have to account for shrinkage  and distortion etc. Maybe not a problem to cast but the project seems perfectly suited to the new technology available .

 

Brad

 

[bradsan]

Hugh

 

Was reading another post with a link to https://patents.google.com/

Went down the rabbit hole thinking I might find a drawing of the part searching for AC Speedometer.

Best I could do was this one showing the side profile and then an improvement filed in in 1928.

https://patentimages.storage.googleapis.com/8d/c0/3a/cf864c590d8774/US1812510.pdf

https://patentimages.storage.googleapis.com/e4/4c/22/9b2e3660971d77/US1690355.pdf

 

Interesting site to say the least!

 

Brad

 

[Crazyfamily]

8 hours ago, bradsan said:

Hugh

 

Our speedo was rebuilt 6 years ago by either Bob's or Bill's ( can't remember now!). It came with no warranty as the pot metal disintegration process never really stops . I am definitely interested in this part. I can't tell you which of the two options we need as the speedo is assembled and I don't want to take it apart until it isn't working! Likely get one of each!

Why not just scan it and create a file to work from? Gary Ash on this forum seems to have a lot of knowledge and sources on 3D printing.

Any thoughts on doing the speedo body as well ? They are made of the same 'crummy' material and I can already see problems around the shaft input threads on ours.

 

    'Why not just have it lost wax cast ?  Far less expensive and it can be made from bronze or aluminum. '

As I recall  , the piece interlocks with the body with some pretty tight tolerances which is one of the reasons they crack when they swell.  The sample part is already distorted from the cracking and swelling so you would have to fix the dimensions before you did any casting ( I think I just answered my scanning question! Maybe scan first and then adjust the scanned drawing to fix any distortion? ) Plus, its a tiny part and you'd have to account for shrinkage  and distortion etc. Maybe not a problem to cast but the project seems perfectly suited to the new technology available .

 

Brad

 

 

Brad I am calling “Bob’s Speedometer” tomorrow to see if they have replicated the problematic pot metal parts for these AC Speedometers.  

 

I watched he’s a few of their YouTube videos and on one of the “tour” videos they mentioned that they have had many of the pot metal parts made now in aluminum so I have my fingers crossed that they now have the parts we need.  Not sure if they will sell only the parts  for a DYI repair or if they only restore them and don’t sell parts?!  I’ll find out either way tomorrow morning and will report.

 

Bob’s seems to be pretty popular for speedo/gauge restoration so I have my fingers crossed on this one!  

 

Seems A LOT of us have this same issue with broken pot metal speedos!  

 

Just like Ike they always say, “You can have it cheap, quick, or good.... you can only pick two of these at one time!”  Still holds true with most things today!  You can get something cheap and quick but it usually isn’t any good, you can get it good and cheap, and it won’t be done quick!  And if you want something quick and good, but it won’t be cheap!

 

so true....

 

I’ll report what I find out from Bob’s tomorrow....

 

I posted on a 3D printed group I am in and a few folks offered to help with the file but one suggested markforge as they are now printing in metal!  They can print in stainless, aluminum, and titanium!  Crazy  huh!!

 

 

 

 

 

[trini]

I do not know if this will work. My DB speedo pot metal was cracked all over and I got a reproduction  from  Meyers Early Dodge. Made with aluminium . "reproduction guys " in Australia does reproductions. Reproduces stuff for almost any car including foreign. .Go to Meyers early Dodge site and you can access  "Reproductions"  from there.. But any purchase  will have to be through Meyers. SEND THE BROKEN PARTS TO MEYERS, WHO WILL FORWARD IT TO AUSTRALIA. AND THEY WILL MAKE IT WITH ALUMINIUM OR WHATEVER  metal IS REQUIRED. They reproduced a complete UX2 carburetor for me. and a gas gauge base.. 

[Spinneyhill]

3 hours ago, trini said:

"reproduction guys " in Australia

http://www.vintageandclassicreproductions.com/Catalogue.htm

[trini]

1 hour ago, Spinneyhill said:

http://www.vintageandclassicreproductions.com/Catalogue.htm

Thank you , Spinneyhill, Sometimes I do not readily remember names.  You see I am 83 and a half and cannot keep my hands clean, must get it greasy. Have been a grease monkey since the age of 16.  

[Hubert_25-25]

Brad, 

     There are 3 pot metal parts to the speedometer.  The speed wheel yoke, the odometer section, and the main support housing.  I have yet to see a speedwheel yoke in 1 piece that has not been JB welded.  This is what I am making.  The odometer section being bad is maybe 1 in 4.  This would be the next area.  I have a couple good ones of these.  Maybe this part would be good to lost wax cast?  These are not as prone to failure.  The main support housing is another being 1 in 5 being bad.  These are usually bad where the cable connects and someone has stripped the threads.  I do not plan to make this part.   

 

So I have been filing on the first pass 3D printed part and drilling and tapping on it.  It is interesting working with plastic as I usually work with metal.  The strangest thing is the tendency for a hole to wander some so I really have to support the part well while drilling.  Some of the model basic dimensions are off so I need have those fixed first.  There are 2 different styles of yokes, and the existing 3D part is made where it will only do 1 of the styles.  Not enough material there to do the other . There are also some key elements that were never incorporated in the model that are required to make the speed wheel function.  The first montage photo shows some of the issues with the first pass 3D part.  Too much copying of the original expanded part and hoping that this can be simply adjusted in the model and print another part that works better.  So I do actually have one working, but I want to make the part require minimal rework after printing.   I also want to go thru the calibration process and see how accurate these speedometers can get.  I do not want to put the bezel on until all the issues are resolved as the bezels are not made to come off frequently.   This is real progress.  

Hugh

Edited September 16, 2019 by Hubert_25-25 (see edit history)

[Crazyfamily]

As I mentioned to Hugh before I am highly considering purchasing a resin 3D printer.  I purchased my youngest son a Ender 3 Pro 3D Printer last Christmas and while its great to learn on, the strength of the printed part pales in comparison to a resin printer.

 

Once the part is printed in resin it then cures via UV bath or exposure to any UV source aka the Sun!

 

The result is a more precise and stronger printed component!  The price is these resin printers have come down significantly over the past year or two so even a starter resin printer does a great job at producing a good strong component!  

 

Once we we can get the files completed an accurate for each component that’s now crumbling in pot metal, we could then crank out the needed parts for others who may need them without the extremely high cost of having a speedometer refurbished and the time consuming task of finding a donor speedometer!  We all know how fun that is!!

 

I am amazed at the kindness this group oozes, the willingness to help others.... mostly you all helping ME is very much appreciated and very heartwarming to say the least!

 

Also, I am getting assistance from a member of one of the 3D Pronting groups I am a part of on Facebook!  His name is “Sase” and when I posted asking for assistance he jumped at the chance to help and expects nothing but cold beer when we get the part correct!  Hugh and I have discussed doing more than that when we get this project completed that’s for sure!!!  Sase has his mechanical engineering degree and has years of experience in design and implementation of 3D printing!

 

So to say we are excited is an understatement!  Anyone who wants to help along the way is welcome!!!!

 

High yet again..... THANK YOU SIR!!!!!

 

 

 

 

 

Edited September 18, 2019 by Crazyfamily (see edit history)