Tapping Bottle Stopper Blanks

[Katsin]

Tapping newbie here.

I am tapping wooden blanks for my bottle stoppers by hand and this is working out all right but I feel like there should be a better way to do the tapping. Are there good techniques for tapping with higher precision?

I tried leaving a blank secured to my drill press after drilling and loading the tap into the drill press... turning the tap by hand as I brought the tap down with the drill press, but this didn't work out at all so I immediately went back to tapping by hand.

Is highly controlled tapping a specialty of milling machines?

Using a 5/16" drill bit and tapping a 3/8" x 1/16tip thread.

 

[Jim Burr]

Nothing wrong with that. I use a tap/mandrel from Ruth Niles and run the speed on my 1642 down to 50rpm. Hand taping should work just as well.

 

[Justturnin]

Here is a link to a post I made a while back how I do my stoppers.

http://www.penturners.org/forum/f19/how-i-make-my-bss-97132/

Not sure if it will help but I hope it does.

 

[monophoto]

I've tapped a few by hand. Yes, that works, but there is a risk that the tap won't remain exactly on-axis when it is done purely by hand. And when that happens, the metal stopper won't sit squarely on the turning leaving a gap partway around the seam between the metal stopper and the turning..

You can compensate for that by using a forstner bit to drill a rabbet in the end of the blank before drilling the hole. Measure the metal top of the stopper, and then use the next larger standard forstner bit. The rabbet doesn't have to be very deep - 1/16" is usually enough. The purpose of the rabbet is to hide the seam between the metal stopper and the turning so that if there is a slight gap, it won't show when the stopper is in the bottle. Drill the rabbet first - you can center the 5/16" bit on the hole left by th spur on the forstner bit, but not the other way around.

More recently, I have been drilling stoppers on my lathe with the blank held in a chuck and the drill bit held in a Jacobs chuck in the tailstock. In that situation, I can leave the blank in the chuck, and replace the Jacobs chuck in the tailstock with a live center, and then use that to center the tap in the hole. Just make sure to use a tap that has a centering dimple in the end (some manufacturers omit that dimple - saves about 2 cents of manufacturing cost).

And when I drill on the lathe, I still put a slight recess on the bottom of the turning. I think the finished product just looks better if the seam is hidden. In that case, rather than using a forstner bit, I use a gouge to smooth off the end of the blank, and cut a slight recess, before drilling the hole.

 

[Katsin]

Nice writeup. I like the CA reinforcement idea so I will give that a try on my next attempt.

I did just start doing the forstner bit technique to inset. Works great. Had to get a 13/16" bit just for stoppers though...

 

[KenV]

There are three styles of taps in a set --

Taper
Plug
Bottom

Taper has lots of long taper with only the bottoms of the theads and starts straight. Bottom cuts full threads to the bottom of the hole and is hard to start.

Easiest is to use a taper tap to start threads and then recut them with a plug or bottom tap. Starting with a bottom tap is damn difficult, and a plug is hard to get started straight consistently

You do not need 100% threads and will get better hold with fewer torn thread with a slightly larger drill bit up to 11/32 inch

 

[Katsin]

I did not know about the different styles. Good to know!

 

[TellicoTurning]

As of this past week I don't worry about tapping my bottle stoppers... my friend sent me a video about using a pin chuck to do bottle stoppers... he also brought over a length of 3/8" steel that I cut a flat on and used a cut off 8D nail as the pin... with the length of steel in the collet and a 3/8" hole drilled in the blank, it turns beautifully... I probably won't go back to turning them any other way.

I don't do a lot of the metal cones anymore, but when I do, I can screw them into the 3/8" hole and with a drop or two of thick CA, they fit fine and don't come out.

 

[nava1uni]

As of this past week I don't worry about tapping my bottle stoppers... my friend sent me a video about using a pin chuck to do bottle stoppers... he also brought over a length of 3/8" steel that I cut a flat on and used a cut off 8D nail as the pin... with the length of steel in the collet and a 3/8" hole drilled in the blank, it turns beautifully... I probably won't go back to turning them any other way.

I don't do a lot of the metal cones anymore, but when I do, I can screw them into the 3/8" hole and with a drop or two of thick CA, they fit fine and don't come out.

Sounds good. I did the same things with a transfer punch.

 

[opfoto]

I have a problem with turning by hand....
I drill w/ the 5/16ths bit slightly deeper than the thread on the Ruth Niles stoppers, reinforce the hole with thin CA, tried to use the mandrel in the headstock with the lathe off because the slowest speed is 500rpms (jet mini) and my threads still are stripping out. Now I have a few unusable blanks and I don't want to ruin anymore. IS there a way to stop wasting my blanks?

 

[opfoto]

I meant tapping by hand.....

Update I tried using a hand tap, I believe it was of the taper type and the same thing happened. I then tried to use the hand tap to start the threads and tried to follow it with the Mandrel tap from Ruth Niles....and that faired only slightly better.....I am out of ideas and down to one more blank..But I will use the mistakes for learning opportunities and flip them end for end and try again.....tomorrow night!

 

[monophoto]

Marc -

End grain is more difficult to thread than face grain, and end grain in hardwood is even more difficult. Some woods simply thread better than others.

As you know, my experience is limited, but here's what I've learned by trial and error:

1. Thread must be cut slowly. Trying to power-tap using a tap in either a lathe or a drill press is not going to be successful. I prefer to thread on the lathe because I am more likely to get the threads centered on the axis, but I turn the spindle manually with the tap held between the hole in the blank and the live center. I use a wrench to keep the tap from spinning.

2. Ken mentioned that there are three kinds of taps. It's helpful to start the thread using a tapered tap, and then run a bottoming tap in to clean up the threads and cut to the bottom of the hole.

3. Using some CA to reinforce the hole before starting the thread helps a lot. Then, put some more CA on the threads made by the tapered tap and allow it to cure before running a 'bottoming' tap in to clean up the threads and cut all the way to the bottom of the hole.

4. Ernie Conover suggests applying either wax or mineral oil to the hole before cutting the threads. I've never done that because I can envision that screwing up the eventual finish on the stopper.

5. If that still doesn't work, you can salvage the blank by turning the stopper between centers, and then using dowel/silicone sleeve style stopper. If the threads in the hole are really buggered up, you can often just force the dowel in. Worst case is that you have to chuck the dowell into the lathe and take about 1/16" off the diameter. I glue the dowel into the blank, and then smear a bit of silicone caulk/adhesive around the dowel before slipping the silicone sleeve on.

 

[dogcatcher]

I tap mine sitting in my easy chair in front of the TV, basically just like monophoto posted in his description. I eyeball the 90 degree to the hole and go after it with a tapered tap, then drop some CA glue in the hole to strengthen the threads. Move on to the next one, and keep on until I am finished with the batch. Then I go back and use a bottoming tap to clean out the bottom of the threads. On real soft woods I sometimes CA them again, on normal hardwoods I don't.

The wood will give enough that when it is screwed on to the PSI bottle stopper mandrel it comes out square. Rarely do I have to trash one because I was not tapping 90 degrees to the blank.

 

[opfoto]

Louie,
Thanks for the advice and the detaile info, here is more details,
I am using the 4 pack of exotic blanks I picked up at the show in Saratoga from Curtis lumber I believe. They are East Indian Rosewood, Bocote, Cocobolo, and Blackwood, some oily stuff! I also tried a block of walnut. I understand that endgrain is touchy to drill and tap. I don't use anything for power. I turn the spindle by hand as well while it (the mandrel) is in the headstock. I then tried to do it freehand and faired no better....It was a larger hole obviously going from the 5/16th drilled to 3/8ths but no threads. This is where I gave up and thought I saw Murphy running out of the shop!
Dogcatcher-
Thanks for the response,
I will be giving it another go because I never thought to use the CA after the taper tapping and before bottom tapping. The woods I am using seem to be oily and that may add to my headaches....but as I said if I have to flip them end over end I have a few more blanks to mess up.

 

[KenV]

Louie,
Thanks for the advice and the detaile info, here is more details,
I am using the 4 pack of exotic blanks I picked up at the show in Saratoga from Curtis lumber I believe. They are East Indian Rosewood, Bocote, Cocobolo, and Blackwood, some oily stuff! I also tried a block of walnut. I understand that endgrain is touchy to drill and tap. I don't use anything for power. I turn the spindle by hand as well while it (the mandrel) is in the headstock. I then tried to do it freehand and faired no better....It was a larger hole obviously going from the 5/16th drilled to 3/8ths but no threads. This is where I gave up and thought I saw Murphy running out of the shop!
Dogcatcher-
Thanks for the response,
I will be giving it another go because I never thought to use the CA after the taper tapping and before bottom tapping. The woods I am using seem to be oily and that may add to my headaches....but as I said if I have to flip them end over end I have a few more blanks to mess up.

You will have better success drilling a larger hole -- an 11/32 hole will work better for example.

The 5/16 is the metal work drill size for 100% threads. In wood, it is really hard to get the tops of the threads cut and they tear. If there is not enough clearance, they all tear out.

50% of the height has plenty of strength and tear out a lot less. Even in metal, 75% or 80 percent threads will develop full strength - but not as pretty.

Ruth Niles instructions are:

"Use the stub bit as there's less chance of it wandering when it hits hard grain. Use a 11/32" or 9mm bit and drill the hole 5/8" deep; the stud on the stopper is 1/2" so the 1/8" further allows more glue room. You can see a stub drill bit on the "Stopper Styles" page."


By following her instructions -- you will have lots more success.

 

[opfoto]

Ken...
Funny you mentioned this.....I posted awhile ago then I went to her site and reread the instructions. I also learned that they round the blank first. I will give it a go again tomorrow night and see how I do with the added information I go from the site. I will also add in the drawbar as well and see it that helps too. But there was a conflict in information, 1 spot said you need 5/16ths allthread or similar, and another said it was 1/4 sized. I'll check mine and then get that too. I wish that the Mandrel came with flats on it so that I could use a wrench as needed but that is another issue for later. I'll report back tomorrow night and fill you guys in with how I made out. Again Thanks to all that responded.

 

[opfoto]

Long-Winded Update...get your coffee 1st!

Update....
I flipped the blanks end over end and gave it another try. I repost all the details in case someone else has similar issues or if someone sees a mistake and suggests a change. Sorry for the length of this post.

I set my lathe at the slowest speed of 500rpms, Mounted the blank into 4jaw midi chuck and drilled with a 3/4 in forstner bit for a 1/16th-1/8th in recess as suggested above. Left the blank in the chuck then I used the dimple to start the 23/64ths stubby bit that came with the stoppers and mandrel kit from Ruth Niles. Drilled 3/4in into the blank. I decided to leave the blanks in the chuck and do the drilling as listed to remove 1 variable with mounting the blank multiple times. I did swap the forstner bit with the stubby as I only have 1 jacobs chuck.
Noted the stubby bit did not wander/wobble with the end grain in any of the blanks as compared to drilling with the longer 5/16ths bit I used last night. The forstner bit needed finger pressure as I saw a slight wobble depending on the blank used. I am very pleased with the improvement in that part of the process so far. What a difference!
I then decided to try the tapping again. I started with the taper tap in the block by hand then held the handle and turned the blank as slow as I could making sure I maintained the 90 degree angle the best I could. I tapped the hole until it bottomed out at 3/4in. I unscrew the tap carefully and dripped a few drops of thin CA into the hole while spinning the blank to spread it around. I then did the rest of the blanks the same way. When the 5 blanks were done I used a Qtip to spread the CA around ea hole. I did note a difference in the quality of the thread depending on the blank, meaning I could see a difference in the cut depth. So I am hoping that Ken is spot on with less than 100% thread depth is all that is needed. It really didn't take as much effort to cut the threads as compared to my efforts last night.
All in all I am very pleased with the progress I made tonight. I will finish the tapping with the mandrel tap tomorrow night and see how that goes.
Again many thanks to those that gave me their hints/tips.

I really appreciate the help.
Marc

 

[opfoto]

Final update....

I tapped by hand the 5 stoppers with the tap mandrel that came with the Niles kit.
The tap mandrel looks like it could qualify as a bottoming tap that Ken mentioned describing the three taps made. I started the tap slowly as directed and they ALL tapped just fine. I made sure to "bottom out" the tap then I then gave the threads a coating of thin CA for each of the blanks. I will turn these and will see what happens.
Thanks again for all the assistance.