Gemmer Steering Box

[Otahuhu]

I have two Gemmer marked steering boxes both right hand drive One has a cast Gemmer with the number 21529 then 2 under the 9. The other has Gemmer cast on it along with the number 21539 Also a number 628  stamped on the body  The difference I see is the length of the steering column one being shorter than the other.

My question is are these the correct gemmer box for the 1929 Stutz ? Also are there any parts available for for this model of gemmer ? Thanks   

[edinmass]

215 series Gemmer boxes are all diffrent. The case is diffrent for each application, also the ratio of the box changes with application. Length of shaft for the wheel depends on body manufacturer and body style. Basically you need the correct box for each application. New steering columns both inner and outer have been reproduced in the past. It's an expensive box to repair, and if done incorrectly you up a creek without a paddle. The box also uses bearings that are no longer available. If your case is damaged or the worm is no good your in serious trouble. Right hand boxes are impossible to find for any application. Currently we have four Gemmer 215 series boxes in the shop undergoing restoration. We do them about once a year in small batches, as machine shop set up is very time consuming and thus expensive. We see many boxes sent to us ruined by people who don't have the skills or knowledge to properly service these units. We probably have done thirty or forty of them over the last ten years. Costs run from about two thousand and up for a correct rebuild. It's easy to spend three or more depending on issues and the amount of new parts required. We use to make new worms, for left and right hand drive , but the company is no longer in business. Do a search on this Fourm under Gemmer and you should find a few posts showing a rebuild of a 215 we did several years ago. Ed

Edited October 11, 2016 by edinmass (see edit history)

[Otahuhu]

Thanks for your reply Are you saying that  for say, a 1929 Stutz model m the hourglass worm used in that steering box can only be used on that model? When you produced these worms did you make a complete range for a number of different gemmer boxes or are all 215 gemmer box worms the same ?

[dan at larescorp]

The main thing you need to make sure of is that you have a matching worm gear and sector shaft. If you use a different input (With worm gear installed) and try to use the old sector shaft you'll run into binding issues. I'd be happy to try to ID what you have if you'd like to email me pictures of the steering gears.

 

Send them to danjones@larescorp.com

 

[edinmass]

Every application is unique to the year,make,and body style. We made several diffrent worms, to change the ratio of the box. The L-29 cars steer hard, so we changed the ratio to make it steer easier. Most damage is cause by running them dry, and then modern adjustments made by people who have no clue on how to set the box up. You CAN NOT set it up correctly in the car. We have done more of these than anybody in the last fifty years, they must be set up on the bench. Ed

[Otahuhu]

Ed I agree that these should be set up on the bench obviously as the gemmer box has a hour glass worm with the pitman arm roller as the follower both would need to be set  to follow the pitch circle diameter of the worm, with the end float preset You say your supplier is out of business Have you considered making these on a 4 dimensional CNC mill ? Are you prepared to share the drawing of a worm you made for a 1929 M8 sedan ? Regards Len 

[edinmass]

Hi Len,

           This project was underwritten by two collectors who put up large investments with no guarantee of success. The drawings belong to one of the collectors engineering company. Hundreds of hours were spent on this project. Many others tried to do this project over the years, none were successful. This worm is much more complicated than you realize and can't be manufactured using a CNC machine. Add to that metallurgy that will blow you mind away, obsolete bearings that are no longer available, matching new chrome tubes, steering column shafts of assorted lengths and finished machining, machining the box for modern seals and bearings, and designing the Teflon seal that goes between the box faces, and your only at the tip of the ice berg. New roller wheels with correctly designed bearings, roller axle and nut, grinding everything to tollerance, ect,ect,ect. The only reason the project was done was the dedication of three car people who decided they would see the project through to the end, we spent years looking for a gear cutting shop that would take on the project, in the end there were only three machines ever made that could cut the worm, and only one of them was made for production work, and it's still in use in South America today. The other two were built in 1908 or something like that. The worm stays stationary while the machine works around the part. Craziest thing I ever witnessed in my life. The actual gear cutter / engineer worked out the whole thing using a slide rule and pencil and paper. He held all dimensions to three tenths. The large manufacturing machine can be set up to make them like they did when new, but they won't make less than 500 units, so they are out of the running for making any more. 

 

We tossed out a bunch of them until the heat treating got worked out, and even then the first installed box suffered a failure. We finally got it right after more than a year working on it. I am quite sure it will never be done again, it was a hundred times more complicated than I realized when we began the project. It took a lot of talented people to pull it off. Even then, setting up the box is not a toss it together proposition. With all parts in hand it takes a lot of time to get it set up and working correctly. The box is at its tightest point when steering straight ahead, read the Gemmer info on it in the national data book, and it will become clear why these are so difficult. If you search the Fourm under "new Stutz Gemmer steering gears" you will find a post from Janurary 18 2011 with photos and cost estimates that ended up being way low back then. With two boxes you should be able to get one good one when your done, but remember RHD worms are now impossible to locate. Make a bad mistake and you won't drive your car. The total numbers of RHD cars we did in Pierce and Stutz was less than ten, and I think we made all new worms for them except one. Search for some of  my other posts under Gemmer and you can see quite a few photos of boxes we did. Did I mention FedEx lost a box in shipment from down under to our shop? You don't even want to know how that worked out. We could build your box for you using your two, assuming it has a good worm between them. Best guess is that is a 50/50 chance or less. Our upgrades with bearings and seals, new shafts, ect would run you around three grand give or take plus shipping. If your interested it would be best to call and speak to John in the shop about it. Currently we are so busy that it would be 18 months to get the box done. Ed

Edited October 14, 2016 by edinmass (see edit history)

[Anthony StuartSmith]

On 10/12/2016 at 8:59 PM, dan at larescorp said:

The main thing you need to make sure of is that you have a matching worm gear and sector shaft. If you use a different input (With worm gear installed) and try to use the old sector shaft you'll run into binding issues. I'd be happy to try to ID what you have if you'd like to email me pictures of the steering gears.

 

Send them to danjones@larescorp.com

 

 

[Anthony StuartSmith]

I have a gemmer pat. 2-dg steering box with a two tooth sector shaft with is in my 1927 Studebaker Erskine, the worm gear is extremely worn. Would you know where I can get parts or another box or a upgrade replacement . Anthony from the U.K. 

[edinmass]

Nothing is available .........if it’s right had drive is almost impossible to find any parts......left hand drive you might get lucky and find a used box.......maybe, but it’s slim picking nowadays.

Edited September 12, 2020 by edinmass (see edit history)

[Anthony StuartSmith]

I think I have found a metal working workshop that can possibly cast a new worm gear, he does this sort of things for veteran Rolls-Royce and Bentley etc

[JV Puleo]

It VERY doubtful that the gear is cast and, even if it was, it would have to be machined all over so why would you cast it to begin with. I doubt any casting would be adequate for the kind of pressures and tolerances needed for a steering worm. As it is, even with a machined worm, the heat treating is critical. Without the original specs a I suspect (never having seen one) that it is a worm gear with an odd lead (the amount of spiral the work piece makes while the worm is being cut). I also suspect that it could be done - one at the time – but it would require calculating the lead and maybe a special cutter. All of this would be fantastically expensive. It's possible that the gears Ed had made were hobbed (a different way of cutting them, much more production oriented) and that there never were many hobbing machines capable of the necessary adjustments.

 

This one of the rare cases where "reverse engineering" is extremely difficult. The required tolerances and specs are simply too demanding. With a lot of serious engineering know how a very clever machinist with firm grasp of gear & worm making might be able to figure it out but it would require a lot of time...not to mention the trial & error failures which are bound to occur.

Edited November 3, 2020 by JV Puleo (see edit history)

[edinmass]

It can’t be cast. The worm on a Gemmer can’t be done on modern equipment. We made them fifteen years ago. 

Edited November 4, 2020 by edinmass (see edit history)

[JV Puleo]

4 minutes ago, edinmass said:

It can’t be cast. The worm on a Gemmer can’t be done on modern equipment. We made them fifteen years ago. 

 

That's what I expected. This is a good example of a part that was designed to be made on the machines - or probably a specialty machine - available at the time. This is a critical part of design and we can't assume that modern machines can always replicate it.

 

Some years ago I was contacted by a gentleman who wanted to replicate the Sharps-Borchard falling block rifle action...his problem was the machine shop he was using was all CNC and the folks there couldn't make it...he found it difficult to imagine that you needed 1890 vingage machines to make this 1890s piece.

[Gary_Ash]

Ed, I think, as was suggested above, that a modern CNC machine with 4th axis drive for shaft rotation should be able to machine a steering box worm.  It might have to make one pass for one side of the groove and another pass for the other side to provide the tight fit at the center and looser fit at the ends.  It takes a proper understanding of 3D geometry and good programming.  As Joe Puleo has posted on cutting your water pump gear, the cutter can do its job as the bed goes side to side and the shaft axis rotates.  What we don't have for Gemmer and Ross worms is the drawing that defines the actual shape of the groove.  But, as you mentioned in an earlier post here, the heat treating of the machined part is another issue entirely.  [I see Joe is posting as I am typing.]

[Gary_Ash]

P.S.  If my $200 3D printer can produce a copy of Degas' "Little Dancer of 14 Years", surely a CNC machine can make a steering box worm.

 

[edinmass]

The Gemmer has a triple taper and no modern machine can make it. There were two production machines made, and one is still in use in Argentina in a tractor factory. I can’t properly explain why, but the worms were used in the high end cars.......Pierce, Cord, Stude President, Stutz, we looked all over the world, and we found one old time gear cutter doing specialty work who asked for a sample. We flew out to Oklahoma and met with him, and he explained that the design was only used in Gemmer boxes and Otis Elevators. He had to make an adaptor on his machine to do the project. The material stayed stationary and the machine moved around the material. His machine was made in 1911. It was miles over my head, he worked out everything on a slide rule and pencil and paper. Fastening to observe. The first piece was correct and useable. The worms were 2k each twenty years ago......we made two runs. We also made different ratios for the L-29 to make them steer easier......sold them all fast. We also made worms for left hand drive on Pierce and Cord. Overall the engineering, heat treating, bearings, seals, prints.........it was a lot of work. And the rebuild was not cheap when one adds in parts, labor, and machining the box. We probably did 75 in total. Ed

Edited November 4, 2020 by edinmass (see edit history)

[JV Puleo]

WOW! That is no ordinary worm gear. It's hard to imagine what the machine looked like...I'd certainly like to know what it was, if only to see if could study the patents.

 

 

[edinmass]

It's a triple hour glass tapered worm........craziest thing I have ever seen.....took me a month of looking at it to understand it. Some day over a beer, I will tell you the whole story. IT took three years from start to the first unit. Just the prints were a nightmare. 

[Cadillac Fan]

https://patents.google.com/patent/US1821945A/en?oq=1821945
 

is this it? 
 

 

[Anthony StuartSmith]

Figure 4 in the diagram (worm gear) in the exploded view is exactly what I’m after

[edinmass]

1 hour ago, Anthony StuartSmith said:

Figure 4 in the diagram (worm gear) in the exploded view is exactly what I’m after

 

 

That is a "normal" worm, and not difficult to make. It can be done on a modern machine. It won't be cheap. Heat treating is difficult to get correct.......