Thread chasing - newbie level 1

[greybeard]

To learn how to cut/chase thread is one of my aspirations for 2007!

I've watched the Sorby site vid clips, and googled around a few sites, but I'm having difficulty finding reading material that is at a simple enough level for me. Most of it assumes a level of understanding/ability way above mine!

I should explain that I don't have a technical background, so I prefer to read around a topic (sometimes reading quite a lot around!) before beginnning to try and put it into practice.

There appear to me to be two types of tool - one a die-type (? the round bit with a sharp edges on the inside that cut when wound on?) that is done on a stationery piece of work, and one where the pressure/cut is applied directly by holding or passing along a hand tool against the wood whilst the target piece is moving.
I assume the benefit of the latter is it's flexibility of size?, so not restrained to one size (like a die)?

To my un-tutored eye the thread cutting of metal tools and those for thread cutting of wood look very very similar - I'm referring to the inner and outer toothbrush-like looking tools (well, sort of like a toothbrush).

Which of course makes me think that the difference must be in the detail, and presumably something to do with the shape of the tiny cutting teeth? My deduction would be something along the lines that metal is cut pointy, cos you can! Wood thread is cut - say - rounded, for durability/wear.

Can anyone confirm whether I'm making a major error or a minor step forward in understanding the 'mechanics' of the process? In fact better still, can anyone point me in the direction of some reading material?! That would be v v appreciated.

Ta in anticipation

(apologies to mods if I've got it wrong - not sure if this is the right place? I though it could possibly appear in the hand tools section?, or the turning section? But then thought that here was good too?)

 

[Travis Byrne]

Good morning greybeard
Hear is a place to get some insight on wood threads.
http://www.sawmillcreek.org/showthread.php?t=13851
Some of the tool stores sell tap and dies sets for wood just like metal.
The big differance between wood and metal threads is the number of threads per inch (TPI). Wooden ones are much less threads per inch.
I am sure someone will come along and give more info on the subject.
Welcome to the forum bytheway.
Travis

 

[tigerturnings]

...can anyone point me in the direction of some reading material?! That would be v v appreciated.

I've never read it myself, so I have no idea how good (or otherwise) it is, but the book that springs to mind is "Making Screw Threads in Wood" by Fred Holder. Amazon has it for just under a tenner, for example.

I'll be keeping an eye on this thread too since thread-chasing is something I've tried a couple of times and failed at thus far.

Cheers

Neil

 

[dickm]

Like others, I've found this tricky. There have been odd articles in both the turning and general woodworking mags over the years, and even instructions on how to make dies for cutting male threads. I've never had much luck with a far eastern 5/8" tap and die set that I bought years ago, but have managed to do some successful threads using bought and home made chasers on the lathe. It's an acquired knack, and you waste an awful lot of bits learning!
As well as needing to use a much coarser pitch in wood compared to metal, another difference between threading wood and threading metal seems to be that with wood, you need to cut "from the outside in" (i.e. cut into the wood from the surface down) whereas metal taps/dies seem to cut from the bottom of the thread to the surface. If you see what I mean!

 

[Inspector]

http://forums.taunton.com/fw-knots/messages?msg=7987.11

greybeard

If you don't mind joining the "Knots Forum" you can read and look at pictures of the jigs and blade my father used to cut treads with a table saw. The biggest he tried were 4 inch in diameter.

I'd repost it here but it's late (4:30 AM) and I don't want to put the pictures on a hosting site.

I have the book by Fred Holder and it does describe all of the common methods with a few tips to make it easier too. I was going to suggest it, but tigerturnings already had it there!

 

[greybeard]

Thanks guys, that's given me a lot to be going on with.

I'll let you know how I get on - but please don't hold your breath!

 

[ByronBlack]

greybeard, please keep us updated as to your progress as this is something i've thought about quite a lot recently. I've a number of jig idea's drawn up and often wondered about how to create wooden threads instead of always using thread-inserts.

 

[Losos]

Hi Greybeard,

I can't help on the wood side (I probably know less than you on cutting threads in wood) but since you ask about reading material I would like to offer this:-
'Nuts, bolts, fasteners, & plumbing handbook' by Carroll Smith
ISBN 0-87938-406-9

It's by an American race car builder and driver and is very easy to read. He demystifies a heck of a lot in the metal fasteners field.

I particularly liked his explanation of why 'spring washers' are a waste of money on anything over about 5mm (Say 3/16") I had a lot of problems with 'spring' washers and didn't like using them but didn't really know what else to use. Smith gives a logical and clear explanation in Ch.7 and I have never used them on larger size bolts since reading it.

Sorry, it's all about metal fasteners, but well worth a read IMHO and no, I have no connection with him at all.

 

[Colin C]

greybeard, please keep us updated as to your progress as this is something i've thought about quite a lot recently. I've a number of jig idea's drawn up and often wondered about how to create wooden threads instead of always using thread-inserts.

Hi BB

You could use one these for cutting your treads.

I have a few

 

[SVB]

Try google search for John Berkeley - He is THE thread chaser in wood.

Also, if you are going to give it a go then the type of timber is equally important as the technique. Close grain, fine timer is really the only type to learn with. Box is preferable but some fruit woods are ok also.

Best option, get in touch with John or someone local and a 1/2 day lesson will save you hours of frustration and let you enjoy what you are doing.

After all, aren't hobbies supposed to be fun?!?!?

Best of luck.

 

[RATWOOD]

HI greybeard
Try http://www.johnberkeley.co.uk/

 

[greybeard]

Another big thanks for the advice, tips and encouragement guys. The speed, depth, and width of response on here is truly startling. Strange as it might sound I was almost beginning to go off the idea cos I couldn't seem to find a place to start, let alone to get into it!

Just in passing I think I've maybe detected a certain wryness in some of your comments, so I think that maybe I have an even longer learning curve than I'd begun to think might be the case!!
Still, Rome wasn't thread chased in a day I'm sure.....why has my brain suddenly linked to a BBC comedic offering entitled 'in ever decreasing circles' or something like that? - I have no intention of producing such circles! But I bet I can!! And will!!!

 

[Russell]

If you are cutting threads with a lathe then the best video I have come across is the one by Alan Batty called "Thread Turning" it is probably the best one around.