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.
On 12/30/2015 4:15 PM, Ivan Vegvary wrote: ...
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, though.
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...
That object is in the general class of "rivnuts"--tighten it the first time and lower section collapses--it's intended to be installed in sheet metal, not deep holes.
I would simply drill and tap it. You might be surprised how well a simple 5/16" tapped thread works in hardwood.
Use a slightly undersized drill for the hole, do it on a test piece first. If you have a drill chuck for your lathe, then you can drill and tap it on the lathe. If you are afraid the threads won't hold (they will) you can put in some super glue after tapping and then re-tap the threads.
I think this would be better than the standard threaded inserts because they typically are not very long and provide less support, particularly lateral support needed on a shift knob.
Very simple to do and should work w/o much fuss.
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 know.
Even a "fine" thread? I wouldn't think there'd be much thread to hold in wood.
Exactly, the insert suggestions are cool but simply making it complicated IMHO.
Just another observation--this is a shift knob IIRC. Unless it's completely symmetrical you want it threaded in a manner that lets the alignment be adjusted--if the threads are cut in the wood then it may be necessary to shim or trim it until it aligns just right, if it's a threaded insert the insert can be turned a little bit as needed, if it's a press in insert then the insert can be placed on the shifter and then the knob pressed on.
Here's another option:
If you want the full installation kit with the purpose-made drill, tap, counterbore, etc it's a bit expensive
I suspect that just drilling a tight hole and using anchoring epoxy will be sufficient with the 3/4 inch long insert though.
It would be fine as long as the threaded hole is perpendicular to the grain.
If parallel to the grain the tap will shear/break off much of the threads as it cuts. That is true even with larger NC threads. There are various ways to fix that but the easiest thing is to drill a larger than needed hole, fill it with thickened epoxy or JB Weld or similar, let it set then drill and tap the epoxy.
Shifter knobs generally use jam nuts to tighten and orient them.
Make sure it is comfortable in the hand during use. A pointed top should be avoided.
readed 5/16" 24 tpi. Have tap.
"x24 nut. If embed rhen how?
uce a small spiral. Have not glued together yet, nor have I cut the narrow
1/8" or so strip of wood.Threaded insert is a good option. But do it the easy way, put the insert i n FIRST, then chuck up a bolt or threaded rod, thread the insert and blank on and turn your gear shift knob. You KNOW the insert is both dead centere d and perpendicular to the gear shift.
Deb
depends
how long is the threaded shaft what kind of wood does the shaft have a collar that the knob cinches to
i might go all the way thru the knob and put a nut on the top and put a nut on the shaft and have the nut recessed into the knob bottom
use thin nuts
epoxy the nut in the knob top
then i would find an old pontiac key fob and use clear epoxy to cover the top nut with the key fob
this way you only have a 5/16 hole in the knob with recess at top and bottom for the nuts
drilling it depends on what tools you have
this is a case where drilling the hole first is best before turning
what happened to the first one you made
or did you never make it
a year ago you asked the same
which model pontiac is it anyway
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.
HTH...
...Kevin
Is the shift lever on the floor or the tree? If the floor, you won't see the hole as it will be on the underside.
And to add to that sage advise, use another nut to double nut the insert while turning. Then it won't rattle off or move while turning. The nut can be remove on the car, but I think I would have it there as well.
Mart> >> Making a gear shift knobs for daughter's 1948 Pontiac. Shift shafts is threaded 5/16" 24 tpi. Have tap.
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