Thread cutting

[boysie39]

I have seen a tool for cutting threads on the big selling market place on the bay
Has anybody got one of these and if so are they value for money .
I have not tried to chase threds but would like to try I think from the look of it
it seems to be fairly eegitt proof hence the intrest from me.
If you have one and dont want to admit it ,just say you seen some turner using it
and give your opinion on it :lol: :lol:
Thanks in advance

 

[marcros]

Eugene,

I assume that what you are looking at is something like a tap and a threadbox (sometimes called screwbox)? What sort of diameter are you thinking of using it on? Ideally you want as few TPI as possible for wooden parts. If you buy a secondhand one, make sure you get one with a matching tap- they can be a pain to match up afterwards.

They can be a pain to search for on websites because they often fall between various catagories. http://www.oldtools.co.uk/tools/Other_M ... Tools.html usually have a few.

It might be worth searching the forum for somebody that has produced something with one, and asking them about there experiences. I appreciate that is what you started the thread for, but I hoped I could add a few words that would be useful to your quest.

The alternative, I suppose would be something that fits onto the lathe, and screwcuts like a metal lathe would. I would be interested to see this, because it has a good application of being able to cut wooden leadscrews.

Mark

 

[Wildman]

Any thread cutting will require a fully variable speed lathe as very slow speeds are necessary. I have a number of hand chasers for metal not tried on wood yet as speed seems far to fast for me to retract at the end of a pass but will try in the next few days. however as an experienced wood machinist I'm sure you would have no problem using any such fleabay device

 

[flh801978]

Funnily enough I was looking at buying one of these a few days ago.. I have the ball turning jig that this boffin makes and thats fine.I asked for any more information and he sent a review that was in woodturner as a pdf and the reviewer said whilst it works well he wouldnt bother with it.
It looks to me like a copy of the jig that Bonnie Klien used to sell.
The cutting tool fits in the headstock and headstock wants to go as fast as possible the bit looks like a router bit so I would imagine that it wants/needs to go at 20,000 ish whereas most lathes only go to 4000 tops
Then the work is held in the jig on your chuck and advanced into the cutter and it cuts a 16tpi thread form 1 mm deep ....though apparently soon there will be other pitches available...maybe worth waiting for the improved model..
Ian

 

[loz]

Any thread cutting will require a fully variable speed lathe as very slow speeds are necessary.

Variable isnt necessary - but a low enough speed is,

I chase fine at 400rpm - the lowest speed on my 4 speed DML.

 

[flh801978]

I'm fairly sure that boysie is looking at the machine/jig i was on about in my post where the bit revolves and cuts the work . fast is best. hes not looking at thread chasers i'm sure

 

[marcros]

I think there are 3 threads running here.

1. boysie
2. my assumption that he was talking about threadboxes
3. wildman talking metal cutting threads/lathes.

together they are getting a bit confusing, particularly the discussion re lathe speed, and involving those discussing 2 and 3!

 

[jumps]

I think there are 3 threads running here.

1. boysie
2. my assumption that he was talking about threadboxes
3. wildman talking metal cutting threads/lathes.

together they are getting a bit confusing, particularly the discussion re lathe speed, and involving those discussing 2 and 3!

at least 4 surely, there's talk of normal thread chasing as well #-o

 

[loz]

OOPS,

Eugene what are ye talking about ? - Chasing ( doing it the fun way ) or one of the lazy machines ???

 

[Spindle]

Hi

I have three sizes of screw boxes with associated taps ranging from 1/2" to 1" they work very well with dense straight grained wood, (I tend to use beech for male threads - female are more forgiving and tend to work OK in most woods).

I also have a set of the Sorby thread chasers which I have seen demonstrated live working well on box wood. They were a bargain I couldn't resist but as yet I've not used them.

So - if it's screw boxes you're referring to I can recommend you go ahead and purchase - I bought mine from Axminster.

Thread chasers are a little more demanding I think, but having seen them being used by an accomplished hand they're a skill I will be aquiring in the future.

Regards Mick

 

[NikNak]

Boysie....


I was put on to these peeps by Richard Findlay... http://www.tracytools.com/ and ordered a 'pair' a while ago. I think it's a bit hit-or-miss as to whether they have what you want (i seem to recall mine came from the 'clearance' section), but quite helpful peeps.

Here's a little taster of something i've twizzled....

made from a piece of holly

this is a piece of pear wood


Both i recall were roughed to shape then had to be 'drenched' with CA to enable the thread chasing (neither woods really suitable for thread cutting). Very slow speed, mine goes down to 200 rpm.


Give it a go.... i did (homer)



Nick

 

[flh801978]

I think this is what boysie was asking about
http://www.ebay.co.uk/itm/WOODTURNING-L ... 43ae6a89fe

 

[Wildman]

Ok all singing from the same hymn sheet now, I was formally talking about thread chasing in wood not metal. This system uses a single point tool and could easily be used with a router on a stand rather than a lathe. The wood to be threaded would be held by a chuck on the device and is advanced simply by turning a screwthread that the chuck is attacked to. a very effective way to cut an external thread of a single pitch. but will not do internal threads so you are left with half a job done. On the plus side changing the angle of the cutter will allow a different thread form to suit available tap but the total length that can be threaded is limited by the length of the chuck feed screw and unlikely to be more than a couple of inches at most. 16tpi is quite a fine thread once you get to larger diameters. Some 16 tpi taps are available 7/8 x 16 and 3/4 x 16 tpi whitworth form are conduit but taps are expensive £30 -70. 3/8" x16 is a standard whitworth thread, 1/2", 9/16" are BSF and 3/4 x 16 UNF so a few taps and sizes are available. If you have a good selection of taps then it could be useful however if you are thinking of threading large diameters or long pieces then not of much use.
Of course I could have it all wrong yet again and be shot down with yet more buckshot in my posterior after all what do I know about anything.

 

[marcros]

Ok all singing from the same hymn sheet now, I was formally talking about thread chasing in wood not metal. .

Apologies- but all from the same hymn sheet now!

 

[Jonzjob]

I made one of these

And for doing ths

I got one of these as well

http://www.axminster.co.uk/axminster-ax ... prod21303/

 

[Wildman]

now that would work well using a woodruff type cutter in the chuck, would cut internal and external threads a treat. Cheers for the idea for infeed (depth) then a very simple arrangement could be made on a hinge principle as per early drummond roundbed.

 

[jasonB]

A woodruff cutter won't work as there is no relief and the cutter won't follow the helix angle. Same as trying to screwcut a square thread on an engineering lathe without grinding clearance on the tool.

And 7/8x16 taps are available from about £12 not £30-70.

J

 

[Jonzjob]

It possibily is not the taps you are goig to be paying for but the dies as well?

As for the rest of the jargon, I have not a clue :? :? :?

 

[jasonB]

It possibily is not the taps you are goig to be paying for but the dies as well?

As for the rest of the jargon, I have not a clue :? :? :?

I thought the point Wildman was making was that the jig will cut the external 16tpi thread but you would need to buy a tap to cut the mating female thread.

Infact that jig will cut internal threads anyway thats why thay say from 1" dia upwards as the cutting tool wont fit inside anything smaller.

J

 

[Wildman]

A woodruff cutter won't work as there is no relief and the cutter won't follow the helix angle. Same as trying to screwcut a square thread on an engineering lathe without grinding clearance on the tool.

And 7/8x16 taps are available from about £12 not £30-70.

J

I said woodruff type (not form) and a small dia cutter will create its own threadform like a hob it is a common way to mill threads. The price I quoted was the price I had seen for Whitworth form threads UNF are much cheaper. Anyway enough of trying to be helpful after 50 years in Engineering I obviously learnt nothing apart from how to create argument. I'll stick to asking stupid questions rather than trying to help anyone. Obviously thats all I'm fit for practically every post I have made over the past few days has been picked on really not what I was looking for in a forum.