Making gear shift knob for daughter's '48 Pontiac. Think cigar. End needs to be tapped 5/16 inch tbreads.
Question: Try and drill after turning? Hard to hold contoured product. Only have spur center, no chuck.
Drill first and place in lathe using a home-made 5/16 step arbor?
All advice appreciated.
Ivan Vegvary
On Wednesday, December 17, 2014 2:01:44 PM UTC-6, Ivan Vegvary wrote:
> Making gear shift knob for daughter's '48 Pontiac. Think cigar. End need=
s to be tapped 5/16 inch tbreads.=20
> Question: Try and drill after turning? Hard to hold contoured product. On=
ly have spur center, no chuck.
> Drill first and place in lathe using a home-made 5/16 step arbor?
> All advice appreciated.=20
> Ivan Vegvary
What tdacon said, but with this difference, since you have a tap for the th=
reads, I would assume you also had a die of the same size and thread. Turn=
a blank, thread it and insert in your gear shift blank (after you have dri=
lled and tapped it, of course) then insert your threaded piece. place on th=
e tailstock end and turn.
The reason to drill first and turn later is twofold. 1)you have more mass =
to stand up to the stress of the drilling process and 2) you can center off=
the hole, rather than trying to center the hole, which almost never works.
"Ivan Vegvary" wrote in message
news:[email protected]...
Making gear shift knob for daughter's '48 Pontiac. Think cigar. End needs
to be tapped 5/16 inch tbreads.
Question: Try and drill after turning? Hard to hold contoured product. Only
have spur center, no chuck.
Drill first and place in lathe using a home-made 5/16 step arbor?
All advice appreciated.
Ivan Vegvary
That last sounds pretty good. Drill first and, for the tailstock end, turn a
stepped piece that fits the hole fairly closely. You wouldn't want to put
the drilled end directly on the tailstock center for fear of splitting it.
Tom
On 12/17/2014 3:01 PM, Ivan Vegvary wrote:
> Making gear shift knob for daughter's '48 Pontiac. Think cigar. End needs to be tapped 5/16 inch tbreads.
> Question: Try and drill after turning? Hard to hold contoured product. Only have spur center, no chuck.
> Drill first and place in lathe using a home-made 5/16 step arbor?
> All advice appreciated.
> Ivan Vegvary
>
I did a large batch of ultra-high-power refrigerator magnets from exotic
woods featuring a semi-precious stone disk set in the end. The magnets
required the insertion of mild steel cups and these needed to be
bolted/screwed into a recess in the wood. I finally figured out that I
could drill and epoxy a threaded brass insert into the recess made for the
cup. Then I could easily used a threaded steel rod screwed into the brass
and clamped in a chuck for the drive end. Doing it this way it would be
possible to bring up the tailstock to steady things during the roughing
process although with my small pieces it wasn't necessary. As the last step
I chucked a Forstner in the tailstock and used it to cut the recess for the
stone disk.
"Ivan Vegvary" <[email protected]> wrote in message
news:[email protected]
> Making gear shift knob for daughter's '48 Pontiac. Think cigar. End
> needs to be tapped 5/16 inch tbreads. Question: Try and drill after
> turning? Hard to hold contoured product. Only have spur center, no
> chuck.
> Drill first and place in lathe using a home-made 5/16 step arbor?
> All advice appreciated.
> Ivan Vegvary
You could drill a 1/4" hole first, partially glue in a 1/4" dowel
("partially" so you can more easily remove it later) then turn. If you
make a somewhat sloppy 1/4" hole and glue a piece of paper around the
dowel with water soluable glue you should be able to get it out easily
enough and then tap the hole.
The tapping is what I really wanted to comment upon. You said "think
cigar" so I'm assuming the tapped hole will be in end grain. Isn't going
to work. Not well, at least. The tap is going to be cutting across the
grain making many tiny, insecure little pieces, most of which will break
off. I had the same problem when cutting 1/2" threads on my cane. I
solved it but it was neither easy nor entirely satisfactory. You would do
much better to epoxy in a metal insert that also has internal threads.
--
dadiOH
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On Wed, 17 Dec 2014 12:01:40 -0800 (PST)
Ivan Vegvary <[email protected]> wrote:
> Making gear shift knob for daughter's '48 Pontiac. Think cigar. End
> needs to be tapped 5/16 inch tbreads. Question: Try and drill after
> turning? Hard to hold contoured product. Only have spur center, no
> chuck. Drill first and place in lathe using a home-made 5/16 step
> arbor? All advice appreciated. Ivan Vegvary
Is it three on the tree? I'd want a metal shaft all the way through.
The wood would just be covering the metal shaft. What's the original
look like? Maybe make a pin chuck for the lathe, they're handy.
https://www.youtube.com/watch?v=Odu1cT3AwUE
I think someone else suggested turning a morse taper, mount in
headstock and drill. Let us know what you come up with. I
always like to hear about new and novel approaches. There are so
many ways to do these things. I think that's half the fun.
I like to challenge myself to make do with what I've got instead
of buying some new tool and often I learn something new as well.
On Wed, 17 Dec 2014 12:01:40 -0800 (PST), Ivan Vegvary
<[email protected]> wrote:
>Making gear shift knob for daughter's '48 Pontiac. Think cigar. End needs to be tapped 5/16 inch tbreads.
>Question: Try and drill after turning? Hard to hold contoured product. Only have spur center, no chuck.
>Drill first and place in lathe using a home-made 5/16 step arbor?
>All advice appreciated.
>Ivan Vegvary
What do you have for the tail stock center?
A Cone center maybe?
If you have a cone center, drill and tap the blank, chuck it up with
the drilled/tapped end on the tail stock - just don't over tighten or
you will split it.
If you don't have a cone center for the tail stock, take a threaded
rod or cut off bolt (5/16"), and drill/punch a dimple in one end (make
sure it's about 1" longer than you need. Drill and tap the blank,
screw in the threaded rod/bolt. Put the wood end on the drive center,
and the theaded rod/bolt end on the tail stock.
You could also make a wooded MT#2 (or 1 depending on your lathe) with
a threaded rod sticking out of it - use it instead of the drive
center. Then screw the drilled/taped blank onto it.
Gimp