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This might be a source:Quote:
Originally Posted by Roger Zimmermann
https://nwsl.com/collections/worms?_=pf&pf_t_mod=Mod%3A%200.5&pf_t_type=Type%3A %20Left%20Hand%20(LH)
Keep up the fantastic model building! It's a pleasure to see your progress. It's like a kid (me) watching a master (you) at work.
Hello Roger! (and Markus!)
I came across a technique for making knurled parts that might also create a small worm gear. -Using a tap of whatever dimension, you like, chucked into a lathe, and feed a free spinning disc of brass against it. Pressing onto the edge of course. It's an experiment but will create a fine knurl. Matching the tap, which would be chosen to match whatever screw thread you like.
I have not done this myself, but I did see it demonstrated. The engagement of the thread might not be as deep as you might like as most taps are designed for 75% depth, and that might be an issue for slippage, backlash or stripping.
-Don
PS- There was a convex curve previously cut into the edge of the disc, to help guide the tap and insure proper engagement.
CUTTING A WORM GEAR WITH A TAP
https://bing.com/videos/search?q=mak...+with+a+tap&ru
Thanks to Charley for the link. I found the worm I can use; it's another matter for the worm gear. There are part numbers which can be used, but there is no way to find them! I just ask the company for help. I will report here how the matter is coming. Anyway, there is some light at the end of the tunnel!
To Don: fun system! I prefer not to pursue this adventure because if I could get the gear, I would still not have the worm. As you can see above, the solution is not far away. Anyway, thanks for the reaction/help!
To Markus: thanks for your comments!
Model A has outlined an accepted procedure for cutting worm gears with a tap. Cutting a gear requires careful calculation and set up to ensure that the gear teeth match up as the cut approaches full circle. In your case, you do not need a complete gear, only a sector. Because there is no need for teeth to mach up, you are free to choose any radius of the sector which the job requires. Because you are working with light cuts, and only a few teeth will be needed, it should be possible - if tedious - to unplug the lathe for safety and work it by hand.
Hello Roger. -is it as hot there in Switzerland as it is here? 104' F today!
Anyway, the wheel part of the worm gear, gearing, needs to have a circumference that is an even multiple of the pitch. But it can be any multiple. Large or small.
The worm would of course be a section of threaded rod. Needs to be the same pitch, so it could be 8mm with a .5mm pitch, but the wheel could be 100mm in circumference.
I plan to try this out this weekend, as I have a 3-day weekend.
I'm not sure where to measure the circumference, minor diameter, deepest part of the threading, or major diameter of uncut wheel, or an average?
I'll let you know.
Thanks to all for the comments and suggestions. I will order the LH worm and a gear from about 30 teeth to have the appropriate distance between input and output shafts. I will search a bit more with the module .4 to have a better ratio (it should be 1:17 according to the specifications).
Don, as I'm only dealing with the metric system, the middle diameter is gotten with the module multiplied with the number of teeth. Example: .3 x 30 = 9mm. The outside diameter will be about 10mm. However, this would give a 1:30 ratio which is a bit too much...but will do a very light steering! The weather is much cooler those days; sometimes rain (still not enough) and temp. about 20°C (68°F).
Edit: after looking forward and backward at the listing, I opted for a worm module .3 and a gear with 28 teeth and a worm module .4 and a gear with 21 teeth.
With the module 0.4, I will have to enlarge the housing for the worm compared to the ideal dimension; with the module 0.3 I may have difficulties to have the proper distance between both shafts. I will just use the set which will fit the best.
Hello Roger, on the 1:1 scale Cadillac, how large is the steering wheel? Pre-power assist, I imagine it has quite a presence in the drivers' compartment? A teacher of mine, back in High School had a 1940-something convertible and I remember the steering wheel being big. -and it taking some effort to crank around. Lock to lock a turn and a half?
According to my measure, the steering wheel was 18.5" Unfortunately, I don't know how many turns lock to lock. Probably 4 to 5.
While doing the steering gear arm, I noticed "ears on the side. Suddenly, I found the reason for those ears. Do you have an idea about their purpose?
Attachment 37217Attachment 37216
The better to hear you with!
Sorry, I wanted to beat Jo to the joke.
In the one photo, the doubling of nuts are reflections. (Took me a moment to figure that out.)
And in the other photo, you can be seen squinting into the camera.
Maybe to allow the use of a "Gear Puller", in removing / adjusting the position on the spline?
Bingo Don! I'm not at 100% sure, but I assume the ears were there to extract the arm either with a tool or just with a hammer.
For different reasons, the steering gear is coming slowly as expected: first, I realized that the worm and sector must be a reverse set. Thanks to this forum, I could order the appropriate set. This was just before our autumn vacation, so I expected to have the gears at my return. They were there, but I came back with Covid's! Thanks to the vaccine, the illness was not too severe, but I was "out" for a good week.
Anyway, I could begin with the steering gear's partial body, the tube and shaft. I have now to make the sector shaft and its body and connect it to the main body.
The whole will be a tight fit as the exhaust tube is very near from it. I hope that there will be no conflict...
Attachment 37254Attachment 37255
Hello Roger, very glad to hear that you are well!
-I guess we will have Covid in our lives forever now?
I am curious as to how you will proceed. With the steering box, that is.