Jerry Feather

One of the parts of my original or very early concepts for this T-handle was or is the need to plug the opening in the bottom of the shift shaft bore liner before injecting the rubber compound, mainly so that the compound cannot find its way into the bore. Later on, it occurred to me that using the collection of wine bottle corks/stoppers that we have saved for some reason from our previous drinking days, might fill the bill, so to say. Of course they are too big around, so I decided to try to turn one of them, a rubber one, I think, in my lathe. That didn't work very well and using the lathe bit takes a long time since I can't hold them in the lathe chuck hard enough to take a very deep cut.

So, I decided to try to use my disc sander to trim one of them down. However, I was not very careful and let the rubber grab the disc and partly jerk it out of my hand. In the process I ground a very nice groove in the top of my left index finger. Now I have that to deal with, but I don't think it will hold me back much. The pain meds I have left over from my back surgery a year ago sure came in handy last night, except that although the pain was eliminated so I could perhaps sleep, the med itself kept me awake.

Anyone have a good idea about how best to trim the corks and rubber wine stoppers down to size?

jetson8859

Jerry, what size is the opening? I have 10-15 rubber plugs that are 10MM bottom and 15MM top that I didnt' use for a previous project and will send them out to you if that helps. Kevin

Jerry Feather

Thanks Kevin. The opening is going to finish out right between 15mm and 15.5mm. I think your corks will be a bit too small. Nice of you to offer. I'll keep working with what I have; or maybe I'll find a hole cutter or punch close to the right size and simply cut some plugs out of some kind of dense foam.

Jerry Feather

It occurred to me that another solution to the problem of closing the shaft openings from the rubber compound might be to simply put some masking tape over the holes and then trim it to the edges of the aluminum tubes. I might try that. I did, however, go out to Doug's shop and borrow his 5/8 inch hole punch and cut some plugs out of some quarter inch closed cell foam. Here is what that looks like.

Anyway, so much for the wine bottle corks and stoppers, I think.

Kevin in Atlanta

If you're going to use tape - I recommend Gorilla Duct tape. I use it to mask off my S4 manifolds before they go off for blasting and powder coating.

Jerry Feather

Thanks, Kevin, for the suggestion. I don't think it will take much, just enough to keep the rubber compound from flowing into the bore while the bore is pointing up with the mold resting to set. The end of the aluminum bore should be fairly snug against that part of the mold, so there shouldn't even be much space for the compound to flow thru.

For progress, there isn't any right now. The .5950 reamer arrived in the mail yesterday and I put it in the chuck in the lathe, but when pushed thru the long pieces it doesn't even touch the bore anywhere. Now I am waiting for the .6000 reamer which appears to have arrived at the local P.O. so it ought to be delivered tomorrow. I have a high degree of confidence that it will be just about right since the long pieces as currently reamed will just start to fit over the shift shaft, so I don't think much more is required. If so, the next step up is to .6050, and I haven't ordered that one yet.

Jerry Feather

I did get the mill set up and cross drilled the small holes at the bottom of the long pieces, the ones for the mounting screws. I tested about every fourth or fifth one in the mold and they are all pretty close. I'll probably measure each of them to be sure, and any that I find off by a significant amount I'll drill the small holes in the other end then mill the bad end out for the cross-bore to mate to the short pieces. I need to get the bore correct before I do the cross-bore, however.

Jerry Feather

I hate admitting when I screw up at given points, but then it is really part of the whole process, at least with me.

In looking at the long piece in the last picture above it appears to be off center a bit. Actually that is just the angle of the shot taken. However, what you can't see is that the long piece is slightly canted in the mold. When I took it out and measured the small holes at the bottom I found that one of them is .150 in. from the end and the other is only .130 from the end.

I went to sleep last night wondering about how that big of a mistake could have been made, then this morning I measured the jig piece I had made for this part of the project and find that the base of it is not parallel to the top of the vise, or the bottom of the vise either, which is where it registers. It was actually off about .050 in. in just less than three inches which throws the holes off just about the .020 that I found. I fixed the jig this morning.

That means that now I have to drill all of them over again, at the other end. Then, as I mentioned before, the bad end will be milled away including the mistaken holes. Good practice, I guess.

Jerry Feather

The .6000 reamer arrived in the mail today so I reamed one of the long cores with it. The bore mikes right at .6000, so it is apparently of good quality. I tried that core on the shift shaft in the car and it fits over it very well. It is dragging a bit on the inside, apparently from the burrs on the two guide slots cut in the top of the shaft. I think I'll file them down a bit and see what that results in. Then I'm going to re-ream the rest of the long pieces and then finish out the cross drilling at the other end and finally mill the cross-bore at the end with the incorrect small holes. Then I should be ready to try the brazing material to join the short and long pieces.

Otto Mechanic

Personally looking forward to the results of that experiment.

Jerry Feather

Me too, Scott.

Yesterday I finished re-reaming the long pieces to the new .6000 size and then set the mill up again and started drilling the new mounting holes in the other ends. Then I put it away for the evening.

This is kind of a minor complex operation since I have to first put an X on the end of the long piece that is going to be milled away for the cross-bore to mate with the short pieces, in the next step, so I don't have to later decide which end is bad. Then I need to deburr the bore in the good end with a countersink in order to be sure that the piece fits correctly in the jig, then re-drill. It just takes time.

Jerry Feather

I have all the long pieces re-drilled at the other end and then I have set the mill up with basically the same tooling except for the 3/4 inch mill bit, and then I am now able to cut the cross-bore in the other ends.

When I milled one of them I find that they fit the welding jig pretty well, except for a high spot that I haven't quite figured out yet, but maybe. I'll have to reset the mill in order to correct for it, and I think I would rather mill all the long pieces first since I think I have the mill set up just about exactly where I want it, and that is kind of a chore.

Here are some pictures of the milling process, and then the fitting in both the welding jig and then in the mold, but without being brazed together yet.

Jerry Feather

When I put the short cross piece into the welding jig and push it to the bottom with the guide slot fit over the flange for it in the bottom of the jig, it lays firmly on the bottom. When I put the long piece in first and slide it to the stop at the upper end it also lays firmly in its slot in the welding jig. However, when I put the cross piece back in on top of the long piece it will not go all the way to the bottom of its slot and it rocks back and forth a bit. That is what is indicating a high spot, as I mentioned before.

It you look at the picture above taken at 19:44 you can see a very small gap between the two pieces where they mate. The reason for that, I am sure now, is that the stop I milled into the welding jig for the upper end of the long piece is holding the long piece just slightly back from its needed position. That is causing the tiny gap and is also holding the long piece out of position just enough to keep the short piece from resting in the cross-bore milled for it. That is why it rocks.

Otherwise everything about the long piece seems to be just about perfect including the resulting length from the bore to the bottom of the piece so it will fit into the mold correctly, and as to the amount of offset with the short piece, which should be right at .120 in. Therefore, I'm going to go ahead and mill all of the long pieces as the mill is now set up and then use the mill to fix the stop in the welding jig.

Here is a picture of the welding jig with my pencil pointing at the offending stop.

Jerry Feather

Actually, there doesn't really even need to be a stop there because the long piece, as milled to mate with the short piece is it's own stop.

dr bob

Jerry -- I'm thoroughly enjoying the thought evolution as you work through the various tooling steps in the way to a production ready setup. Those who haven't been through this before I hope are enjoying the education.

Many years ago there was a machinist on the board, from Florida, who has since passed on. He would regularly lament the concept sketches then engineering drawings he would receive, from people who obviously had no clue as to how the parts would actually be made. There's a very practical procedure-based thought process needed to translate a concept and engineering drawing into a working bit of tooling. My hat's off to you for doing this, and again twice for sharing the process. Know that there are some of us who thoroughly appreciate it all.