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.
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
If the hole isn't perfect, don't worry about it. The epoxy will be
stronger than the threads-in-wood attachment anyway.
"Playing is not something I do at night, it's my function in life"
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
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.
Drill the hole while the blank is still square/rectangular. Then mount
it so that the tailstock is centered in the hole. Turn to the desired
shape, insert the threaded insert, mount a bolt the same size as the
insert into your chuck, screw the knob onto it, and cleanup the side
that was formerly mounted in the chuck.
On Tuesday, December 29, 2015 at 8:41:32 AM UTC-8, -MIKE- wrote:
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.
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.
On Tue, 29 Dec 2015 20:42:37 -0800 (PST), Ivan Vegvary
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
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!
On Wednesday, December 30, 2015 at 7:10:26 AM UTC-8, krw wrote:
That looks like a great product. Unfortunately it only comes in 5/16"x18tpi which is a standard thread. Much less common is what I have, 5/16"x24tpi. Have tap and die, fortunately.
Thanks so much for your reply and research.
Hmmm....indeed, I had trouble finding them in 5/16 UNF, too.
I think 5/16" is probably too large for the knife/edge threaded inserts,
What are you using for the wood? (IOW, I'm asking how hard it is and how
well it'll tap and hold).
What I'd probably do is to bore the hole slightly under-size for nominal
soft steel dimensions for threading, then use some epoxy when applying
the knob to the shifter.
My experience with similar made repairs for a couple old trucks is that
they get sufficient use that they will, eventually, loosen if it's an
"every day driver". But, if it's basically a show vehicle, it'll
probably last as long as needed...
But, they will work as OP wants when there's not much tension force,
just want to ensure the threads don't strip as are wont to do with
(especially fine ones) in wood.
Unfortunately, I couldn't find a 5/16 in UNF, either, so guess we'll not
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