Making a gear shift knobs for daughter's 1948 Pontiac. Shift shafts is threaded 5/16" 24 tpi. Have tap. Would you guys simply drill and tap the turning, or, somehow embed a 5/16"x24 nut. If embed rhen how? Turning is glued-up light an dark wood mounted askew in the lathe to produce a small spiral. Have not glued together yet, nor have I cut the narrow 1/8" or so strip of wood. Help! Thanks
Use a threaded insert. You can find them at any hardware store. Add epoxy if you want some assurance.
Understand threaded insert. But how do I drill axially an object that is kind of freeform and not perfectly cylindrical making it vise unfriendly. Just hold it by hand in the drill press and eyeball? Thank you for answering.
I have done that very thing. You already have a center point marked by the lathe, correct? You can work out some sort of clamping mechanism using scrap blocks, foam, rubber, etc.
But honestly, if you can hold it securely in your hand, that's what I'd do. test the technique with a scrap piece of the same type of wood. Use a Forstner bit which is much less likely to catch or bind than a spiral bit.
If the hole isn't perfect, don't worry about it. The epoxy will be stronger than the threads-in-wood attachment anyway.
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Ivan Vegvary wrote in news: snipped-for-privacy@googlegroups.com:
I think the technically correct answer would be to chuck it in a 4-jaw chuck, mount a jacobs chuck in the tailstock, and drill it that way. I say "I think" because I've never done that, but it seems like it would work well with a lathe if you have the chucks.
What I probably would do is try clamping it in a drill press vise, with some sort of foam to distribute the vise pressure.
John
One problem I see with a threaded insert (after the fact) is that I will end up with a knob that has an almost 1/2" hole mounted on a 5/16" chromed shaft. Gaping hole might not look too good. Suppose I could fill it with Bondo or wood putty. Thank you for all the replies!
I'm not following the level of difficulty you appear to be having. If you're turning the piece, you already have a center hole at each end. Before you do the final cutoff, drill the end, which will be mounted on the stick, with the appropriate size bit using a Jacobs chuck as suggested. Thus, no worries about crooked drilling. Then insert the threaded insert with glue, let dry then finish. Once it's finished, you're ready to simply screw it on.
Ivan Vegvary wrote in news: snipped-for-privacy@googlegroups.com:
If you've already cut off your mounting points, you might try getting some modeling clay and using it to hold the piece for drilling on the drill press. It might be a good idea to cover the piece to avoid contamination.
Puckdropper
No difficulty. Just mentioning that I would rather have the 5/16" chrome lever entering a 5/16" hole in the knobs instead of the much larger hole necessary for the drilled thread insert. Simply a matter of looks.
Easy, would be to get a bit of square steel rod (1/2 x 1/2), drill and thread it, and fit that into a square mortise that you open up from a 1/2" drilled hole. When it slides in easily, add hotmelt glue and assemble (this glue ought to be weak enough that you could disassemble nondestructively).
Alternately, drill a hexagonal hole for the nut (drill it round, vise/chisel to make a hexagonal mortise), or heat a hexagonal item of the right size and press the red-hot metal into the wood...
If you have a metal lathe, you can make a turned insert that has the right clearance hole to engage an inch or so of the shaft, with a threaded end, and knurl the whole thing. I wouldn't force-fit it, though (like many threaded inserts), because the wood might decide to split.
I think many shift knobs are made with through holes, and the open end is capped with a nice logo-endplug, after you get it secured.
When I was doing a bit of teaching in our local woodturning club, "knobs" o f all types was one of the things I taught. I had my own method, and guys that learned it turned gear shift knobs, fine furniture knobs, and decorati ve knobs of all types.
Take your blank, orient it the way you want to get the cosmetic appearance right. Take the end that will be the bottom and take it to your drill pres s. Drill a hole deep enough to accommodate your screw inserts. For a gear shift, I usually used two to three nuts of the correct thread size, depend ing on how long the threaded section was on the shifter.
Take a hex head bolt that is the same thread size as your nuts/shifter, and cut it off about an 1 1/2" above the threads. Using a machine oil like 3in
1, wipe the bolt threads down with a generous amount of oil with special at tention on the end of the bolt. Put the nuts on the end of the bolt. (You can also use a single piece of all thread connector if you can find the rig ht size.) Epoxy your hole, and insert the oiled bolt (oiled to prevent epox y adhesion) with the nuts on it into your wood block.Allow to cure. I usually wait about 12 hours or overnight.
The next day, you now have something that looks like a popsicle.
I have a couple of these, and if you don't have a #2 Morse taper (for mid s ized lathes, #3 for larger) with a chuck on it to hold small stuff you need one.
Put the bolt end in the chuck, and bring your tailstock up to stead the end . Turn out your shape and do most of your sanding. If you will put the in sert slightly below the finished end to be screwed on to the shifter, you c an finish the profile, fine cuts and sanding and never expose the inserts.
When you are 99% through turning, turn off the lathe and back off the tails tock. Since you turned the knob to the insert, it is now perfectly centere d, perfectly concentric, and balanced. It will spin easily and true, and y ou can cut off the mark left by the tailstock pin. Sand and finish, and yo u are done.
I finish some things on the lathe using burned on finishes, and when doing that I finish, then spin off the completed knob while the chuck is holding the bolt. For larger things like gear shift knobs, I take them off the lat he, loosen the bolt ( make sure there is no epoxy adhesion0, then leave the bolt loosely in the knob. I use the bolt like a stem, and simply stick it z(with the knob in it) in a hole drilled in a piece of scrap so I can spra y finish on it.
Doing it this way means you do the entire process safely. No hand holding of wood, no foam or rubber gizmos, no jigs to be made, no through holes or any of that. The finished product looks 100% professional and after your i nserts are set, you can turn out a finished knob in literally minutes.
It's easy, too.
Robert
I would recommend using a nut on the shaft to lock the shifter know with. Get a chrome one, and a chrome flat washer to cover the gap you speak of.
But you won't see it or am I missing something?
If the hole will be cross grain, drill and tap will work; if with the grain, you'll need a threaded insert.
Set the insert flush with the entry surface. No gaping hole visible. Especially if you leave it slightly proud and grind off the excess.
Above 4 replies excellent choices. Thinking of either the chuck and bolt method, or, drilled insert with jam nut pre-installed on shift lever. Jam nut will be round with decorative profile made on metal lathe. Thank you, everyone!
How about:
Something to consider. Wine bottle stoppers with turned decorative pieces are simply screwed straight on to the threads of the metal stopper. I would imagine that your shifter will have a considerably larger and longer threads.
Tap scrap and see how secure it is on the shifter be fore turning.
If this is secure enough mount a blank on a 5/16" bolt with the head cut off and mount in lathe drill chuck and turn.
For a gear shift knob I would use a brass insert, and get a nice nut brass, to lock the knob to the shifter.
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