Spindle pin removal tool survey

[Jeff G 78]

I have done some research and I need to rethink my plan. I was going to use 3/4"-8 acme threaded rod, but once I looked at the actual dimensions of the acme rod, I realized that there will not be enough material to drill and tap the end of the rod for the M12 spindle pin. The problem is that the acme threads are rather tall, so the root diameter is rather small. I fear it will be weak and fail where the spindle pin is threaded into the end of the rod. The simple solution is to go to 7/8" acme rod, but it can only be had in 7/8"-6. I'm worried that 6 threads per inch will make it harder to extract the spindle pins. Another issue is that the cost would go up even higher with 7/8" acme rod. The nuts, washers, and bearings all get more expensive as the rod grows.

I am not giving up and I plan to make at least one prototype puller as soon as I figure out the best combination of parts. If I can get acme threads cut into a coupler like Michael's puller, then I can revert to a smaller acme rod and have an adapter coupler as part of the design. Acme nuts and couplers are WAY more expensive than standard threaded parts, so It would have to be custom made. The other option would be to weld the coupler to the acme rod and avoid the expense of cutting acme threads.

Either way, my puller will use bearings and thick washers so it can be used over and over without mushrooming like Michael's puller shown above. Like I said before, I can buy a puller, but I want to engineer a better one.

[LeonV]

I have done some research and I need to rethink my plan. I was going to use 3/4"-8 acme threaded rod, but once I looked at the actual dimensions of the acme rod, I realized that there will not be enough material to drill and tap the end of the rod for the M12 spindle pin. The problem is that the acme threads are rather tall, so the root diameter is rather small. I fear it will be weak and fail where the spindle pin is threaded into the end of the rod. The simple solution is to go to 7/8" acme rod, but it can only be had in 7/8"-6. I'm worried that 6 threads per inch will make it harder to extract the spindle pins. Another issue is that the cost would go up even higher with 7/8" acme rod. The nuts, washers, and bearings all get more expensive as the rod grows.

I am not giving up and I plan to make at least one prototype puller as soon as I figure out the best combination of parts. If I can get acme threads cut into a coupler like Michael's puller, then I can revert to a smaller acme rod and have an adapter coupler as part of the design. Acme nuts and couplers are WAY more expensive than standard threaded parts, so It would have to be custom made. The other option would be to weld the coupler to the acme rod and avoid the expense of cutting acme threads.

Either way, my puller will use bearings and thick washers so it can be used over and over without mushrooming like Michael's puller shown above.

Like I said before, I can buy a puller, but I want to engineer a better one.

FWIW,

You can always make something better, but it doesn't mean it's a better solution. I'm not telling you not to do it but that plan sounds expensive. If you plan to remove 20 spindle pins, then maybe the economics of it come out better, but for the "casual" spindle-pin remover (i.e. a few sets in a lifetime) it may not be worth it.

[Jeff G 78]

I hear you Leon, but I'm an engineer and I like to tinker.

[LeonV]

I hear you Leon, but I'm an engineer and I like to tinker.

I'm an engineer as well, hence why I made the suggestion! Sometimes we get so caught up in trying to make everything as good as possible that we lose sight of the big picture. Just trying to keep you on the right track.

[Captain Obvious]

Huh? What? Someone want to over-engineer something? What can I do to help? Haha!

[Zedyone_kenobi]

Hey NASA employee here!

I work for the government! I'm here to help!

Hahaha

[GreenZZZ]

This is the bar the CZOT club (Austin) is playing with (part number B7MATR-NF100). Basically a 1" thick alloy steal rod, but they ordered 12" long instead of 14". Softer steal gets the threads stripped. The end of the rod is drilled/tapped to grab the end of the spindle.

Northwest Fastener - B7M All Thread Rods - Houston Texas

[Jeff G 78]

Lee, I spent some time looking at a puller I borrowed. It is the typical cheap 3/4" all-thread with a drilled and tapped end for the M12 spindle pin. The 3/4" black steel pipe has a 3/4" coupling which just fits under the control arm flange and is a very good fit to the bushing. When you step up to a 1" all-thread, how are you dealing with the outer pipe where it presses against the bushing? I would think that it would catch the LCA flange unless it was notched on one side.

I can take pics tonight if my post didn't make sense. Let me know.

[GreenZZZ]

Yeah, I see your point, the rod end would need to be machined down to something like 3/4" and the pipe would need to be reduced on the end. I'm cross posting from CZOT as our regional club message board is not public like classiczcars. The guys there are about a week away from posting photos.

At our monthly club meeting they said it hasn't pulled the threads off, but did snap a really stuck pin in half requiring pulling from both sides. :cheeky:

Edited May 8, 2012 by GreenZZZ
spelling

[Jeff G 78]

Lee,

Necking down the all-thread would work as long as it had a smooth transition between the 3/4" and 1" sections. Otherwise, it will have a stress riser and fail. You could then use a 1" steel pipe with a 1"x3/4" reducer to go against the bushing. The drilled and threaded end of the all-thread should also have a chamfer leading into the threads to match the chamfer of the spindle pin where the threads meet the shaft. At the nut end of the pipe, another 1" coupler could be used to ride against the thrust bearing.

I took a few measurements tonight and the O.D. of the 3/4" coupler (or small end of the 1"x3/4" reducer) is ~1.5" and it is about the perfect diameter for the LCA bushing. The I.D. of a S30 front strut top bearing is a bit over 1", so that would work great for the 1" all-thread to pass through.

I think we are getting really close to having the best possible tool. Using an acme thread *might* improve the tool, but it might make it less efficient due to the course threads. I can buy 1"-10 acme or a 1"-14 standard thread. The acme rod and nuts are about twice the cost of the standard threaded rod and nuts. I think I will go forward with the tool using this design. I might buy 12" of each type of rod and do an A to B test. By testing both thread types of exactly the same tool design, we can answer the thread question once and for all.

If I get REALLY ambitious, I might try to remember how to use CATIA and make a CAD drawing of the tool. In the mean time, I'll draw it by hand tonight and post it as a picture. It will be crude and 2D, but will be much quicker than me trying to use CATIA for the first time in about six years. Even back then I was a complete novice user.

[Jeff G 78]

Wow, it's been close to 20 years since I put pencil to paper and back then, I had a drafting machine. Tonight, I just have a few triangles and an engineering scale to work with, but I'm slowly getting a drawing put together. I'll try to get enough done tonight to post something, but NO LAUGHING at my work. :stupid:

Here is the all-thread drawing. I will try to do the pipe, fittings and bearing tomorrow night. BTW, I might need to increase the length of the 3/4" diameter section of the all-thread after I measure the dimensions of a 1"x3/4" reducer.

Edited May 9, 2012 by Jeff G 78
Added terrible drawing

[GreenZZZ]

The acme rod and nuts are about twice the cost of the standard threaded rod and nuts. I think I will go forward with the tool using this design. I might buy 12" of each type of rod and do an A to B test. By testing both thread types of exactly the same tool design, we can answer the thread question once and for all.

Speaking of cost, I remember a point the CZOT guys made. They put a 1 1/2 hex head on the rod. The wrench was $100. Might be better to weld on a T'd pipe you can put a tire iron into instead of using a big socket or wrench.