DIY: Shift knobs made from rock spheres

I just finished a couple prototypes of these shift knobs made from rock spheres. There are almost infinite varieties of rock spheres, the two I chose are onyx and the green one has marble in it too. There's many other quartzes, jet black obsidian, mahogany (oxidized iron-bearing veins) obsidian, snowflake obsidian, tiger's eye, jade......the list goes on forever. Please let me know if there would be consumer interest in this, because I am very willing to buy a vendor account on this forum and sell these.

These are the finished product, albeit rough finished product.

http://i.imgur.com/vQ5XsGJ.jpg

It starts here. There are quite a few things that you need for the procedure, and most of the tools are pictured here. However, I will not be going into how to drill and tap the aluminum inserts or how to make the jig for holding the rock. I will be covering the drilling of the rock only

http://i.imgur.com/ptkX3Ye.jpg

-BALLS! You can find them for pretty cheap on eBay and other places. Mine are both 2" diameter.

-Drill Press with a low gear (500rpm or so?)

-Hammer (that's a given for any DIY)

-3/4" Plywood (marine grade is best, but I don't have that)

-Safety glasses

-Diamond coated drill bit 19mm

-2" x 3/4" OD x 3/8" screw size aluminum spacer (not optimal, but that's what I could find)

-4 4.5" x 5/16" bolts, washers, and wingnuts

-Devcon 2 ton epoxy

-Lots of wood clamps and such like

-12 x 1.25 tap set

-1 3/4" hole saw w/pilot bit

-27/64" drill bit (for drilling out the aluminum spacer)

-Modeling clay

-Chisel

-Dremel with grinding bit helps sometimes

http://i.imgur.com/3ioHPTs.jpg

The two pieces of plywood have 1 3/4" holes drilled in them with the hole saw you see pictured. There are 4 bolts that are countersunk into the bottom of the bottom piece.

The lower piece of plywood is aligned using the same hole saw in the chuck as a guide. Once the hole saw can fit perfectly into the hole, clamp down the lower piece of plywood and lock the table adjust on the press. There's a bit of an issue here with clearance; the hole saw can barely be removed from the chuck as you see it because the table is so high. This is necessary because the diamond bit is so short.

http://i.imgur.com/OPYTpnd.jpg

The hole saw can now be removed. The bottom piece should be perfectly centered now (okay, not PERFECT). The sphere can be placed in the bottom hole and the top plywood can be slid down on top of it and cranked down with the wing nuts. During this time the diamond bit can be inserted into the drill.

http://i.imgur.com/Omwm6f4.jpg

Oh, and make sure you know where you want the hole to be on the rock. For this rock, it was easy because there was an ugly black spot exactly the size of the drill bit.

http://i.imgur.com/fFr6hjK.jpg

Getting there. Diamond bits should be kept cool and most of them work best submerged. Build a clay dam around the ball that will keep water from seeping past the ball or onto the wood.

http://i.imgur.com/2plbEpE.jpg

Pour the water in!

http://i.imgur.com/Hdf7mbx.jpg

Drill baby drill. You have to let the bit drill itself. The weight of your arm-depending on the drill press-is pretty much how much weight you want to put on the drill press lever. More downforce will just kill the bit. It's slow going, but pretty steady. Keep pulling the bit up to make sure fresh water is getting down there.

http://i.imgur.com/Qv9efBI.jpg?1

The drill is spinning in this picture. The camera works pretty well I guess. The water is turning colors!

http://i.imgur.com/cRj4BXc.jpg

Unfortunately, this bit is not long enough to drill the ~1.5" that I need to before bottoming out. In order to get the extra distance I had to take the bit out and use a chisel and hammer to break the core out. The top section comes out really easy, just one quick tap.

http://i.imgur.com/5gmwkiR.jpg

Looks like this.

http://i.imgur.com/qwPwbMa.jpg

Then you've got to keep drilling until you've reached the depth you want. For me, that was 1.5 inches. Then you can remove the rock.

http://i.imgur.com/i9UWZc1.jpg

The lower section of the core is a lot more difficult to remove. Most of it can be chiseled away easy enough but if there's some left then a Dremel with a grinding bit may help.

http://i.imgur.com/LDwU2Kq.jpg

There's still a little piece of rock down there that I couldn't get out. It's not enough for me to worry about.

http://i.imgur.com/zM01oga.jpg

The aluminum insert can now be installed. The 3/4" insert fits quite nicely inside the 19mm hole (19mm=0.748", but of course the hole is always slightly wider). I used Devcon 2-ton epoxy for it and it seems very strong. It's a 2-part epoxy and one of the nice things is that you can mix the two parts together by rotating the insert in the epoxy. And once you insert the insert, you can rotate it even more to ensure that there is even coverage and an even mixture.

http://i.imgur.com/DlyzOh8.jpg

Those little o-rings on the insert were my attempt at creating a collar for the shift boot. They're not going to work. I'm going to have to think of something else.

http://i.imgur.com/59b1R0t.jpg

For reference, the 2" diameter balls are a little bit small for my hand 2 1/4" would probably be better, but my hands are a little bigger than average, I think.

http://i.imgur.com/Z1Zj1GU.jpg

http://i.imgur.com/IwfEZAi.jpg

I would get down on something like this, providing there is a shift boot collar.

You could always just buy the flossy shift boot collar add-on piece for like $15 and use that.

However, the threads are very large because it is meant to be used on the flossy shift knobs.

I would get down on something like this, providing there is a shift boot collar.

The shift boot collar issue is being worked on right now. I've got thoughts in my head but we shall see how they manifest themselves in reality.

Sweet. Would be cool to see some naturally color-matched pieces to match up with interior / exterior colors.

I agree! For any color you can think of, there is a mineral/rock that will match it. The trouble is finding it, then finding an appropriate sized sphere version of it. Unfortunately, I can't make the spheres themselves.

Would you be able to make some that have design similar to these, Instead of the ball?

http://img.tapatalk.com/d/13/02/11/teza2yny.jpg

Just throwing ideas out there.

Nice! I'd buy one.

Sent from my GT-P3113 using Tapatalk 2

Would you be able to make some that have design similar to these, Instead of the ball?

 

 

 

Just throwing ideas out there.

Actually someone has already requested something like that. The closest I may be able to get at this time is a sort of egg-shaped knob, but probably not something that blocky. Believe me, though, I will make other designs if I find the means to.

Original and self-made - kudos to you!

May have missed it but what is the end weight?

 

May have missed it but what is the end weight?

The end weight of those knobs is just over 6 ounces (~170 grams). Like I said, those are pretty small (2" diameter) and the weight of every knob will vary based on volume and density. I am currently waiting on a couple spheres, each ~2.4" in diameter and each ~ 1.2 lbs (~539 g). That's big volume combined with high density pyrite that achieves that weight.

How about the option of adding lead or tungsten to the middle before installing the aluminum insert? Would allow you to make them quite a bit heavier. ....

Good idea! If I wanted to make them heavier I could also use a brass insert instead of aluminum, but brass is a bit (edit: A LOT) more expensive.

Pretty neat idea! If only stone were more dense, I'd consider making one. I'll stick with my trailer hitch knob.

Like I said, they come in all different densities. Find a pure copper one and it would be pretty heavy. It would probably require an epoxy coating because copper is soft, but it could be done. I'd be hard pressed to find one as heavy as your hitch knob, though.

How about the option of adding lead or tungsten to the middle before installing the aluminum insert? Would allow you to make them quite a bit heavier. The tungsten is probably a bit safe material to use than regular old lead, it's used a lot nowadays in tying flies for fly fishing and the stuff weighs a friggin' ton without taking up too much physical space. To give you an idea of size, the ones in this video are 1oz each. You can buy it in sheets and wire form as well.

 

Tungsten has a density about 2x that of steel, and about 6x that of stone. You could buy 18mm tungsten bar stock from McMaster, then drill and tap your insert. Tungsten isn't cheap, though. A 4" rod 18mm in diameter will cost you $110. My calculations were done for a 1.5" hole and a 2" insert length, so that'd be $55 for the insert and ~$30 for the stone, plus labor. Not the cheapest option...

You'd end up with a final weight of ~0.982lb on a 60mm knob with a tungsten insert.

Better, but still not even close to my hitch knob.

Like I said, they come in all different densities. Find a pure copper one and it would be pretty heavy. It would probably require an epoxy coating because copper is soft, but it could be done. I'd be hard pressed to find one as heavy as your hitch knob, though.

Stone maxes out at around 3g/cc. Steel is 7.87. Copper would be slightly heavier, but not enough to justify the effort.

http://i267.photobucket.com/albums/ii287/bac52/62eccb2f.jpg

i'd be down for an obsidian/silver one if you could add some additional weight to it like the others have been asking.

http://img.auctiva.com/imgdata/1/5/0/2/0/6/1/webimg/470629130_tp.jpg

I think I could reasonably add over 3 ounces (90-100grams) by using brass for the insert. The mass lost by drilling out the rock would vary, but for a rock like obsidian, would probably be around 30 grams. So, all told, a brass insert would add maybe 60-70 grams (up to 2.5 oz.) to an obsidian rock. Keep in mind that some of this weight is slightly below the knob because the insert protrudes out, but most of it is near the knob center.

Depending on how much of the insert is threaded, even more weight may be possible. I will have to see how little of the insert I can thread and still be comfortable with it. Also, before anyone suggests that I go with a larger diameter insert...good idea...but 3/4" diameter is just about the widest possible that will still fit through the boot, and that is what I am using.

Who would be a proponent of a heavier weight knob and would be willing to pay an extra few bucks over an aluminum insert knob?