Making Thread (for lids)

[GothycDesigns]

Hello All, First Happy Holidays to all!

I have seen a couple of turning videos with turning boxes and vessel and the screw threads are done by a secondary machine, not sure what the name of it, but how can one make threads on boxes that do not have this other threading machine?

Do I turn it by hand?

Do I carve it in?

Do I take a lid that has threads and try to screw it on in hopes it leaves an impression, then cut out the grooves?

If anyone does this regularly, please point me in the direction of instructions, web links, pics of the tools. I'm just not mentally seeing it in my mind on how it can be done otherwise. Plus my lathe's slowest speed is 1125, do I need slower yet?

Thanks to all who can share any info.

Ray K.
Gothyc Designs

 

[Ed_McDonnell]

Do a search on thread chasing. Look in your tool catalogs for thread chasers.

Books / DVDs by Alan Batty may help you out if you can't find someone locally to show you how it is done.

Ed

 

[lthorpe]

You can watch videos about thread chasing here.



http://www.robert-sorby.co.uk/

 

[GothycDesigns]

Thanks for the fast replies. I'll definitely look them up. Thread Chasing was the word I was looking for. Thanks again !!

If anymore info, please do send it.


Ray K.
GD

 

[Joe Greiner]

According to CSUSA's blurb in their paper catalog, the recommended speed is about 100 to 300 rpm. Once an initial helix is established, the thread chaser follows itself. But how to establish the initial helix escapes me. I cut some test threads on a dowel off-lathe by hand using a mechanic's thread-cleaning file, but had no luck on the lathe - min speed of 600 rpm was one of the culprits, but a lot of practice seems to be needed, even under ideal conditions. I laid out the initial helix in pencil first.

There are also some contraptions (usually called something like "thread cutting jig" or "threading jig") that work more like a Rose Engine. There are a few sold commercially, and several more DIY. Google is your friend. Here's one by the late Jean Michel:

http://www.atbq.qc.ca/jm2/woodturnjigs.htm (bottom of page).

And another I found:

http://homepage3.nifty.com/manasan/english/diy/turning/turn-1.htm (at about 3/8 of the page, dated Aug. 01/2004).

[Oops! Just noticed you're aware of those "machines." At least you now have some keywords.]

Joe

 

[John Nicholas]

My trials found 80 RPM to be the best for me.

I used Pear that I had soaked with CA to make it very hard. John Berkeley, Alan Batty and others recommend only very hard woods for hand chasing threads.

Like anything else it is a technique and you have a definite rhythm to establish in getting your start.

The motion is mostly circular, with a slight twist when you start the helix or pick up the helix for another pass. Remember, you are chasing threads. Seems to me like you chase the helix, adding depth each pass.

You start at 30-45 degrees off to start the helix or pick it up, twisting the chaser to parallel and cutting as you chase. Complete the female first and then match the male to it. On the female remember to cut a small recess at the end of the threads. This way your male will bottom out against the end of the hole and not at the end of the thread.

John

 

[Walt]

Or you buy or make a threader.

 

[Rick H]

Threader Plans

Where did you purchase or find the plans to build the shop built threader?

 

[john lucas]

I can recommend 2 sources. One is the Book Making screw threads in wood by Fred Holder. It covers all the different ways of making threads. It doesn't have plans to make the screw threading machine but gives you enough information that you can probably design one. The photos are great.
If you have access to very hard woods hand chasing is fun. I mean very hard. Fred suggests Osage Orange, boxwood, African Blackwood, Lignum Vitae, Desert Ironwood. Softer woods tend to tear out. I have access to mostly the softer woods so I bought The Baxter threader. Powered thead cutters will cut in softer woods but you still may have to treat the wood with a hardener or CA glue to cut a clean thread.
If you want to buy one I would suggest www.bestwoodtools.com Look at the Baxter theading machine. This is an extremely well made machine and can be made to fit any lathe.
I'm in the process of building a sort of combination of the router driven machines and the Baxter threader. I don't think lathes spin fast enough to cut a clean thread in softer woods so I'm building a bed to hold the lathe and the Baxter threader. This should give me the rigidity of a lathe, the speed of a router and the accuracy of the Baxter threader.

 

[rbabbittjr]

http://www.bonnieklein.com/product_php_based1.htm

 

[David Somers]

According to CSUSA's blurb in their paper catalog, the recommended speed is about 100 to 300 rpm. Once an initial helix is established, the thread chaser follows itself. But how to establish the initial helix escapes me.

Joe

Joe,

We were lucky enought to have Allan Batty do a demo and hands on session out here a number of weeks ago. He has a terrific way of teaching threads. If his video on it is as simply laid out as his hands on session was it will be well worth it. The cost of a decent set of chasing tools is far less than the cost of the thread making machines. And there is no setup time.

Allans starting advice for the threads, male or female, was to have the opening or start of the area to be threaded have a nice rounded edge to it. This made getting that initial "helix" started easy. I found when I had trouble I had made the rounded area a bit flat and that caused me trouble right away.

Another issue was that you have to train your hands and eye to not pause as you enter each cut. You have to be moving smoothly or the very faint, initial threads will tear.

The quality of the wood also has a bearing on your chance of success. Soft woods are tough to work. Fairly hard, tight smooth grain is best to start on.

And lastly, a thread size around 20tpi is supposed to be easiest to start with.

Craft Supply has his video I believe.

Hope this helps.

Once you chase your first thread it is a kick and you are no longer even tempted to buy a machine. It is so simple. Definately worth learning chasing by hand if you are interested in doing it.

Mele Kalikimaka! (Merry Christmas from Hawaii!)

Dave