Swingup external threading tool

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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. :lol:

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:

--- Quote from: bogstandard on December 13, 2009, 02:27:51 PM ---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

--- End quote ---

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:

--- Quote from: bogstandard on December 14, 2009, 06:33:17 AM ---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

--- End quote ---

Sir Bogs,

I noticed the photo is missing.

Great thread on threading. :thumbup:

Regards

Divided he ad:
Don't mind me.....

Just doing a favour for a friend :beer:

Job done :thumbup:

Ralph.

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