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OKANDKO
3rd September 2021, 06:09 AM
Hello..My headstock spindle is 3/4 x 10 unc and I want to be able to use a drill chuck on it from time to time in order to hold a mandrel for turning bottle stoppers. So far I haven`t been able to find an adapter so obviously I haven`t been looking in the right places. The size I need is female 3/4 x 10 unc to male 1/2 x 20 unf. Does anyone have any ideas. Thanks.

Mobyturns
3rd September 2021, 09:28 AM
You have a fairly unique situation with the adapter, no doubt someone has done it at some time, but not likely to be a stock item. My only suggestion find a tame machinist to make you one in the beer economy or contact Vermec or a local machinist.

bruceward51
3rd September 2021, 09:39 AM
I think I am right in saying that most modern lathes have a Morse taper on the inside of 5he spindle and this is where things like drill chucks and sometime mandrel are fitted. With a 3/4 spindle there is probably no Morse taper and that certainly reduces the options. Morse tapers are also common on drill presses so there are plenty to choose from.
Have you considered a mandrel that screws directly onto the spindle? That might be easier for @ machinist to make.
Bruce

China
3rd September 2021, 02:28 PM
As said above, you won't find any thing off the shelf, a mandrel for bottle stoppers is a very simple affair a person who is proficient with a metal lathe could knock one up in no time

auscab
3rd September 2021, 11:01 PM
I don't understand how a bottle stopper needs to be turned on a mandrel . I have a feeling I'm about to be told that .

A mandrel is a rod or threaded rod sticking out of your chuck so what ever is to be turned on it need a hole through it doesn't it ?

Wouldn't a bottle stopper be made by turning the male part that fits the bottle between centers . The whole thing ?

Or by taking it off the lathe and holding the stopper by the male part that fits the bottle you turn the head ?

And couldnt that be done on a user made Jam chuck ? A bit of wood fitted to the spindle with a suitable hole drilled in it . Drilled on the lathe . And the male part is knocked into that to turn the head .

And if that's right then you could buy a 3/4 x 10 UNC tap on ebay .

3x Sutton HSS hand tap UNC NC 3/4" x 10 RH Taper inter intermediate plug. Used | eBay (https://www.ebay.com.au/itm/193485542350?hash=item2d0ca313ce:g:OzwAAOSwnNFZulbq&frcectupt=true)

And tap threads in suitable wood for plenty of Jam chucks?

powderpost
3rd September 2021, 11:32 PM
3x Sutton HSS hand tap UNC NC 3/4" x 10 RH Taper inter intermediate plug. Used | eBay (https://www.ebay.com.au/itm/193485542350?hash=item2d0ca313ce:g:OzwAAOSwnNFZulbq&frcectupt=true)

And tap threads in suitable wood for plenty of Jam chucks?

I have been making wooden "face plates" by cutting threads in pine now for many years. So, tapping a thread with the appropriate tap is definitely a possibility for making a jam chuck.

Jim

Mobyturns
4th September 2021, 12:26 AM
Several options here - Mandrels & Accessories Archives | Niles Bottle Stoppers (https://nilesbottlestoppers.com/product-category/mandrels-accessories/)

It is not difficult to use a shop made jamb chuck or get a dedicated mandrel made that bypasses using a Jacobs chuck. Or to embed a short length of all thread or a bolt with head removed into a shop made jamb chuck.

China
4th September 2021, 02:15 PM
auscab, bottle stopper mandrel is simply a morse taper with a thread that suits the bottle stopper, you thread the blank on then you can complete the stopper from start to finish without even stopping the lathe.
Then unscrew the blank, add a bit of epoxy add the stopper and the on to the next one. In saying that there is always more than one way to skin a cat have a look here although this i just a straight shank in lieu of a morse taper but same principle.
CWS Store - Bottle Stopper Mandrel 8mm (https://www.cwsonline.com.au/shop/item/8mm-bottle-stopper-mandrel)

Skew ChiDAMN!!
4th September 2021, 03:21 PM
Do you have an existing wood chuck?

If so - and it has interchangeable jaws - it's easy enough to make a new set of jaws to grip small spindles from those cheap white plastic cutting boards.

Even if the jaws aren't interchangeable it doesn't take much to turn a wooden disk, cut it into quarters and use those as spacers within the chuck jaws to grab very small dia pieces.

Without a chuck, you should be able to mount a board to a faceplate and drill a hole in the centre to mount a mandrel.

These can be made with quite a good degree of precision, although they're relatively short-lived. It's basic stuff, although naturally it's better to have a "proper" machinist-made adapter.

But if I had to pay going rates for every time I needed a custom thread adapter for a lathe... :rolleyes::no:

auscab
4th September 2021, 09:16 PM
auscab, bottle stopper mandrel is simply a morse taper with a thread that suits the bottle stopper, you thread the blank on then you can complete the stopper from start to finish without even stopping the lathe.
Then unscrew the blank, add a bit of epoxy add the stopper and the on to the next one. In saying that there is always more than one way to skin a cat have a look here although this i just a straight shank in lieu of a morse taper but same principle.
CWS Store - Bottle Stopper Mandrel 8mm (https://www.cwsonline.com.au/shop/item/8mm-bottle-stopper-mandrel)

Ah OK, I see , that's why its needed . Thanks China .

dogcatcher
5th September 2021, 10:58 AM
Make a mandrel by taking a 2x2x3 inch long blank ad drilling and tapping it to fit the threads of your lathe. Use a good hardwood. Next turn it round, then on the tailstock end turn about 3/4" long tenon to the diameter of your hole in the bottle stopper blank.


Use this as a spur/pressure driver to turn the bottle stopper. Then thread the inside of the hole for the metal stopper end.


You could try to thread the tenon on the driver you made, but it will not last, as a simple tenon, it will last a long time.


Cheap, all you need is the drill bit and tap to fit your lathe headstock.