Swingup external threading tool

[andyf]

The vid was commendably brief, showing all it needed to in those 14 seconds  . I'm really glad the tool seems to be proving itself useful, Bogs. Though it wasn't my idea, I passed it along to the group and was worried about having to slink off into the undergrowth if the concept turned out to have any major drawbacks.

Having successfully inveigled you into all the R&D and actually making one, I'll just have to make one for myself.
Hope the damaged shin isn't too painful.

Andy

[Darren]

I've been eyeing up a lump of steel tonight sitting idley  in the corner probably trying it's best to hide from me ....

So much to do .....

[bogstandard]

Gentlemen,

Many thanks for the compliments, but things are not quite wrapped up yet. A couple more tests to do. I hope they go as well as this one did.

BTW, I found the problem with the camera, I had formatted the card a while back but I have never had to do a vid since, so the problem didn't show. I had formatted it to Fat system rather than Fat32.

Bernd,

I have a shoe brake system on my machine, complete with a drum, just like a car, it is very efficient. I thought this was a lot of backlash on my machine since I had set it up, so just how bad is yours?

Andy,

I would just like to thank Mike Cox again for the inspiration to get me to do a bit of R&D on his concept. This has definitely been one of the easiest projects I have ever worked on to get good results so fast. Usually it takes a lot more thinking power. But of course, the clincher was when John came up with the block idea, it got me past the mental blockage that I had. So the glory is nowhere near all my own, but other peoples' inputs and ideas as well.

If it does go on to really prove itself, I honestly think it will transform the way I personally do threading. But that isn't the main reason. Looking at it, and the quickie sketch I did earlier about a much easier design, it could make single point threading much easier for the people who have been scared to try it out before now. This method certainly makes threading at least 50% easier and quicker. It is a shame it can only be used on a lathe with full reverse on it.

In fact, I think a piece of 2" side by 1/4" or 3/8" thick angle iron would be perfect for the main frame, so don't go looking at big lumps of metal just yet Darren.

Bogs

[Divided he ad]

Nice 


Does as it should as far as I can see.... Nice camera work Stew 



I'll have to look into this threading lark one day...... Suppose I'd best use my 'shop to get that even close to sorted!?




Nice Job John, and then ideas men too





Ralph.

[bogstandard]

So now we come to the final part of this R&D exercise. I made up a very complicated camera mount for my machine, it took me ages, about 15 mins of real hard work.


Grabbed a bit of ali from the recycle box (this was a piece from my original slide for the tailstock mounted DRO head).
Two holes drilled, the end one tapped.




Screwed onto the mag base.




Then the camera was screwed onto the assembly.




By doing that, it allowed me to make this vid, all by myself.
I was talking to Stew yesterday about working while other people are in your personal shop space, and nothing ever seems to go right.
This time, no problems, except you will see at the very end of the vid, I ran out of memory on the camera card.
Before anyone comments, I should have swung the topslide the other way for left hand threading, but for this proving job, I left it as it was, set for right hand threading.

Just to prove I was cutting a 40 tpi thread on that bit of 3/32" (about 2.5mm) brass bar, here is a close up.




Well that seems to be the end of this little exercise. The tool cuts both left and right hand, and John's worry about getting close to the chuck is now no longer a worry.

I honestly don't think that swarf will be an issue. Just keep an eye on it, and if any does get in there, it is dead easy to blow or brush it out.

I was going to make another toolholder, based on the design on my sketch, but because I want to get onto other things, I don't think I ever will. This one will do me just fine for 99% of all the external threading I will be doing, and if I come across something it won't do, then I will just do it the old fashioned way.

I hope you have enjoyed this journey on how I get around to and do things. With plenty of forwards thinking and problem solving, and a little help from friends, you can achieve almost anything.

I do hope that a few of you will be spurred on to make the easier version of this tool, I am sure you won't regret it.



Bogs

[andyf]

Wow, it really is good, isn't it?

Just as a closing note, thanks to Bogs for taking us through everything, and many thanks to Mike Cox. As already mentioned, he floated the idea and showed his prototype on another machining group. I'll invite him to take a look at this thread.

Andy 

[chuck foster]

nice video and better yet, nice threading 
that tool holder is very simple and it looks like it works very well.............now i will add that to my list of things to make.

thanks for taking us along for the ride john.

chuck 

[Bernd]

Bernd,

I have a shoe brake system on my machine, complete with a drum, just like a car, it is very efficient. I thought this was a lot of backlash on my machine since I had set it up, so just how bad is yours?

Bogs

John,

The old Logan I've got doesn't have a brake on it so I'd need to run it real slow for one thing.

Second, when I reverse the machine the chuck will start to turn and at about a 1/4 of a turn of the chuck the lead screw will finally start to turn. Then after the chuck has made almost a full revolution backwards the carriage will finally start to move. Have I made this clear enough to understand? That is one reason I think this tooling will not work in "my" machine.

I'm sure that the gears on the headstock probably have more backlash than they need. As far a the lead screw is concerned, I'll have to take a closer look.

In the mean time I guess I'll just have to resort to turning the cross slide out of the way.

BTW, I'm amazed at how nice that tool follows the thread groove backwards. Great job.

Bernd

[websterz]

  John, that works a bloody treat!  (Did I say that right?  ) The camera mount is icing on the cake...I gotta' build one of those! 

[bogstandard]

Thanks gents, and spot on Webs.

Just to prove I am not all hot air, and that I do use the bits I make, I had a chance to try this out today.

Here is the job ready prepared for threading




Thread cut




Chuck tried and fitted perfectly




The last bit for my interchangeable tooling, a 5c to Myford adapter to fit the spindexer.




I can honestly say that it was the easiest bit of single point threading I have ever done.


Bogs

[andyf]

Berndt: when I reverse the machine the chuck will start to turn and at about a 1/4 of a turn of the chuck the lead screw will finally start to turn. Then after the chuck has made almost a full revolution backwards the carriage will finally start to move. Have I made this clear enough to understand? That is one reason I think this tooling will not work in "my" machine.

To my way of thinking, Berndt, it won't matter if the chuck starts turning (in reverse) before the carriage starts moving. The flank of the part-cut thread will rub on the side of the tool, and move it up out of the way. I can see that if your chuck turned more than 180⁰ before the carriage moved, and you were cutting a small pitch thread, the tool might rise up the flank of the thread and then drop back down the other side of it, but all that would happen is that the thread flank would push the tool up again once the chuck had gone round 360⁰, with no detriment to the tip of the tool.

A simple test could be arranged : Instead of a tool, grip a bit of thin slightly springy metal with a 60⁰ point on the end in the toolpost at centre height, with lots of overhang so it can spring up and down. Engage its point in the thread of a bolt held in the chuck. Then, with the change gears set up for the same thread as the bolt, try running the carriage to and fro. My bet is that the tip of the "tool" will rise and fall as required. If the tip gets mangled, I'm wrong  .

Andy

[Bernd]

Andy,

That sounds like a good test. Will have to try that. Won't be right now though. Thanks.

Bernd

[bogstandard]

Bernd,

When Stew called around the other day, and we cut that very large thread, we encountered a major problem when the tool was deep in, about 4mm (0.160"). On retracting out of the runout, the side of the cutting tool jammed on the side of the thread. It was caused by the swing part of the tool not being able to rise enough to clear. All I did was a quickie hack out of the main tool holder on the top overhang. Once that was done, and the tool could lift as far as it wanted, it just climbed as high as it needed to go, and dropped back into the cutting position when it reached the end, as shown in the short vid.
So even if it was riding on the very top of the tips of the threads already cut, once it had dropped off the end, and if you left enough runup to the job to get all gears back into synch, I don't think you would have any problems at all.


John

[Ned Ludd]

Hi Mr Standard,
I think that is what your "detractors" were worried about, the not being able to rise up enough. Sounds like your fix (could you call it the Viagra modification, getting more of a rise. sorry 'bout the bad joke could not resist) has done the trick.
 
Ned Ludd

[andyf]

Bogs: So even if it was riding on the very top of the tips of the threads already cut, once it had dropped off the end, and if you left enough runup to the job to get all gears back into synch, I don't think you would have any problems at all.

Not sure that gear sync would be an issue, Bogs, because the drive from spindle to saddle will be engaged throughout. Won't the tool just need a moment to drop down again before starting the next cut? Unless you are working at lightning speed, that will happen while you are stopping, changing the spindle from reverse to forward, and starting off again.

Incidentally, Mike Cox has viewed this thread and says "I am amazed that my simple idea could generate so much
interest and discussion. I only wish I had the skill and equipment that Bogs has. It is very satisfying that in the hands of a skilled worker the idea was taken to perfection."

Andy

[bogstandard]

Ned,

When I did the sketch earlier on in this post, it shows the backing plate as an 'L' shape, rather than mine which is a 'C' shape. I did that purely to make it easier for producing one of these tools, and even though I didn't think of it at the time, it automatically solves the problem of allowing the swing to get up high enough. I did mention though that it would allow the swing to be lifted completely out of the way for checking the fit of the thread with a nut. A thing I can't do with mine, I have to retract even further back to be able to get in.

I think that is called a lucky bit of design work, or getting it right without thinking about it.

Sorry Andy, that should really be phrased as 'to take up the backlash' rather than 'back into synch'. But you know what I mean. It will require retracting further as all the gears and shafts will have to take up all the gaps to go in the opposite direction, and won't all be in the correct position until it has travelled a certain distance, some parts will move by friction alone and won't be in the correct place until there are some 'pressures' working in the train.

I'm glad Mike was pleased with the results. It isn't just being discussed on here, but other places as well, and it seems to have had a very positive reaction.
 
Someone has even commented that he might have seen the idea before in a book. But I'm not worried about that, in a book is no use unless all the people who can benefit from this design can see it. We have just brought it out into the open if that is the case, where maybe thousands who haven't got the book can benefit from it.

All I can say is, I am one who has definitely benefitted, 'cos I got one.
You lot will have to make your own.

If he wants any more ideas as good as this one developing, just tell him to throw it open on here, I am sure someone will run with it.


John

[Bernd]

Bernd,

When Stew called around the other day, and we cut that very large thread, we encountered a major problem when the tool was deep in, about 4mm (0.160"). On retracting out of the runout, the side of the cutting tool jammed on the side of the thread. It was caused by the swing part of the tool not being able to rise enough to clear. All I did was a quickie hack out of the main tool holder on the top overhang. Once that was done, and the tool could lift as far as it wanted, it just climbed as high as it needed to go, and dropped back into the cutting position when it reached the end, as shown in the short vid.
So even if it was riding on the very top of the tips of the threads already cut, once it had dropped off the end, and if you left enough runup to the job to get all gears back into synch, I don't think you would have any problems at all.


John

This is what I was trying to get across, but didn't quite get it right in writing. I figured with a deeper thread it would do what you mentioned. But as you say if you give the tool more room to tip up it'll work.

I'm glad it all worked out in the end.

Looks like I'll probably make one of these some time down the road. Thanks again for your presistence on this project.

Bernd

[bogstandard]

As a final act, I have done another rough sketch on how to put one of these together.

There are no dimensions shown as you can make it as large or as small as you want it to be. I am sure the members on here can cope with something like that. The things not shown are the pivot point bits. If you drill a plain hole to use, then a washer will be required between the swing up and the main body. If you fit bushes, as I have done, then the top hat flange will give the stand off required. You should make the step bolt to give a couple of thou side to side clearance. I would suggest giving the locating block a small chamfer on each of the top edges, to assist the tool in relocating itself if it has been completely lifted off the block as it was being retracted to the start.





Get in there and enjoy your screwing.


Bogs

[davidfe]

As a final act, I have done another rough sketch on how to put one of these together.

There are no dimensions shown as you can make it as large or as small as you want it to be. I am sure the members on here can cope with something like that. The things not shown are the pivot point bits. If you drill a plain hole to use, then a washer will be required between the swing up and the main body. If you fit bushes, as I have done, then the top hat flange will give the stand off required. You should make the step bolt to give a couple of thou side to side clearance. I would suggest giving the locating block a small chamfer on each of the top edges, to assist the tool in relocating itself if it has been completely lifted off the block as it was being retracted to the start.





Get in there and enjoy your screwing.


Bogs

Sir Bogs,

I noticed the photo is missing.

Great thread on threading.   

Regards

[Divided he ad]

Don't mind me.....

Just doing a favour for a friend   






Job done 




Ralph.

[Lykle]

I really love these kind of threads (pun intended)

Anyway, all we need to do now is design the same kind of tool for internal threading.
That's the one that always get's me into trouble.

It could be a rotating shaft with stops and maybe a light spring load to keep it down. Or a weighted stop?
I think it would require quite some modification on the relief side of the toolbit, to make sure it does not grab the material while retreating.

Hmm, nice little design project.

Lykle

[andyf]

Hi Lykle,

It would be hard to make a swinging toolholder for internal threads. If it swings up, the tool will dig deeper into the side of the bore, unless the axis around which it swings is very close to the tip of the tool, so the radius of the arc described by the tip is rather less than the radius of the bore. I suppose it might be less difficult for threading holes of large diameter, but it would probably be easier to make a retracting toolholder like the one shown here http://www.gadgetbuilder.com/ToolHolders.html#Retracting , where the operator uses the ball handle at the end of each cut to slide the tool out of the thread so that the carriage can be wound back for the next cut.

Andy

[Ned Ludd]

Hi Guys,
Anybody thinking of building one of those retracting tool holders, should think again. Although it is an interesting project and is indeed nicely designed, it can be replaced by a simple cross slide stop for MUCH less work. The idea of a retracting holder for internal threads has merit but of a completely different design. Something like a round  boring/threading bar in an offset round sleeve, for fore and aft movement, but it would need some arrangement at one end to stop the bar rotating under load. I can see it in my mind but no time to make it real, where is Bogs when we need him?
Ned Ludd

[Darren]

After building and using a swingup threading tool for external threads I wouldn't want to use anything else.

For the little internal work that I may or may never do I'll just do it the old fashion way or use slide stops. I'll work that one out when I get there.

[ieezitin]

On the internal threading tool I don’t think it would be that hard to make here is a quick sketch on the mechanism that sprung to mind.

My theory is you only need to retract .050 - .070 max Linear to clear the cutter for extraction. The actuator could be at the end of the boring bar and a knurled wheel for rotation to seat and disengage.

The beauty is when you hit 0 and 90 of the cam you have great forces working for you so movement or backlash should be minimal if  not zero.

All could be made on a lathe within a day maybe, the hardest thing would be the engineering of the cam and dimensioning after that its cake.


Any ideas please feel free to critique .

All the best.              Anthony.