How to use limit switches in a project circuit?

Thread Starter

fiftyv8

Joined Jan 29, 2018
223
Shortbus, being that I only own 1 guide for 2" dia tube (I think it is too short as it looks to be a clamping piece and not long enough to be an actual wiping guide), how can guides be made at home with minimal machinery to perform the wipe bending process???
 

shortbus

Joined Sep 30, 2009
10,049
This is what kept me from making bending die sets for my JDsquare type bender. The bending die could be made on the lathe but a long straight follower would be much harder. But thinking about it now, I really don't know if it needs to have the radius in it. If I needed a different set of bending dies today I think I'd try it with a squared out opening in the follower, like a "U" shape with a square bottom, that should support the needed areas of the tube. Some times companies get kind of sneaky, making a part with the radius to keep guys like us, that like to build our own things, from doing it at home.

I haven't thought about all this tube bending stuff for years, thank you for a trip down one of my older things I've done.
 

Thread Starter

fiftyv8

Joined Jan 29, 2018
223
Dont worry Shortbus, I'll come up with something that works when the time is right.
In the meantime, I have started to figure out exactly what I want from this machine and decided to cover as many bases as I possibly can to accommodate my mish mash of forms etc.

I've spent a lot of time maching bits and pieces and digging thru my scrap for pieces of metal that will help keep me moving in the right direction.

So far this is what I have worked out.
More to follow soon.
Thanks for your patience.
 

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shortbus

Joined Sep 30, 2009
10,049
That roller may work with the thick wall tube. But you will need to put it closer to the intersection of the former. I guess that would make it tangent but not really, it needs to be slightly off set from the center line of the former radius, maybe like 1/4 inch. If it was on the center line it would make a lot of stress to bending the tube, but if too far from center it would allow the tube to distort or not reproduce accurately the form shape.
 

Thread Starter

fiftyv8

Joined Jan 29, 2018
223
Well more progress in the right direction.
Never easy and it has been slow, but it is starting feel like a test bend will happen soon.
I've been doing quite a bit of figuring out, as to how things need to sit and function.
I have started making an adjustable guide I guess it could be called which will align the tube with the rotating table.

I have also come to the conclusion that this machine needs to be capable of performing the original roll around bending function, but with a quick change over of idle shaft plates it will also be able to perform the wiper style bend process.
I purchased (ages ago from an estate sale) a box of mixed up dies, guides and roller stuff andhave been trying to accommodate these items if possible, since it adds value to what I am trying to do.
Making any of these items is time consuming and may not even be possible with my limited equipment.
To purchase this stuff would be out of my reach, but it remains worthless unless I can attach it to this machine and be able to use it at some point in time.
 

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shortbus

Joined Sep 30, 2009
10,049
The adjustment is essential but again I'd have done it different, to get the roller closer to the bend form. I would have mounted the plate under the pillow block allowing the rollers to be closer to the center line of the bend form center line. With each smaller bend form radius your roller get farther away from the former allowing more spring back and less of a wiping motion.
 

Thread Starter

fiftyv8

Joined Jan 29, 2018
223
I started work on a 2nd turntable component which will become the wiper arm as I have heard them called.
This will be a secondary method or pulling the tube around the form.
The arm with have an adjustable slide that initially will accommodate a guide roller but the roller will be removeable and could be replaced with a clamping device depending on whether the form is locked to the frame and does not rotate or if it is locked to turntable and does rotate.
 

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Thread Starter

fiftyv8

Joined Jan 29, 2018
223
They are M8 x 1.25 pitch metric, round head with allen drive. (M8 means 8mm diameter)
I have a buddy, who has a buddy, who works at some place where from time to time they build/assemble small hydraulic and pneumatic machinery prototypes for testing.
he tells when they are finished they dis-assemble these machines and throw all the screws and bolts away.
His buddy had difficulty doing that so he would sweep them up off the floor and put them in a big bucket and bring them home.
He never used them, especially the quantities he had accumulated so started gifting buckets to close friends.
many took them but never used them either.
My buddy decided that I would be a worthy recipient and so I scored big time.
Trouble is they come all messed up with a mixture of sizes and threads including imperial.
I've spent days working my way thru this stuff and ended up with a pretty impressive stock of paticularly bolts, screw, circlips, pop rivetts and studs or useable sizes.
None of us from the old skool could believe the waste, but I guess that is how stuff is done these days...
Lucky me.
About 25 years ago, I drove past an old junkyard that stored more stuff outside its yard by the road (could not do that these days). I stopped and had a look inside some of the recycle bins stacked outside and to my delight it was filled with a a mixture of new bracket stuff and plastic bags full of imperial nuts. The bags had never been opened. Being that it was a sunday and all was closed I salavaged a number of bags to help them out and moved on. I got bags from 1/4" thru to 5/8" diameter (still using them to this day).
With the fasteners I have at home you would think I'd never need to buy any more, but you know I still find the on occasions that I need to purchase stuff I dont have...
 

shortbus

Joined Sep 30, 2009
10,049
I'm the same way, can't seem to pass up something I might put to use. Almost all of the "junk" I have has a use I planed for it, but age and health seemed to have a different vision than me. I have so much stuff I have to work on cars and such in the drive way and I have a very large garage/barn. The kids are going to have one hell of an auction when I die.
 

Thread Starter

fiftyv8

Joined Jan 29, 2018
223
Just by way of explanation, with regards to that roller I made.
I purchased to small sized roller bearing and one thrust roller bearing.
I machined out each end to accommodate and press in the roller bearings, plus at the lower end I allowed additional space to also install the thrust bearing in the hope that this roller will not be impeded by much drag or friction.
It appears to me that there will be a critical moment in time when bending any tube, which is right at that initial tangent point where full load will be required to convince the tube to let go and comply to the shape of the form.
I'm sure there are more scientific and eliquent words to desribe what I am getting at, but they are not really in my vocabulary.
I figured that I would be better off making that instant point as smooth as possible and hence the use of bearings and not bushes and washers etc...




20211110_142100.jpg
 

shortbus

Joined Sep 30, 2009
10,049
You do know it's original use don't you? They are for marking a center point to drill a hole in a pipe, at a certain angle from level. Nice find.
 

Thread Starter

fiftyv8

Joined Jan 29, 2018
223
As I continue to do the house keeping on this project, I have reached the satge where I need to make and attach a bend angle indicator, probably called a protactor.
I cut out a piece of light sheet metal into a half circle and can see how it could be mounted etc.

However, I am hoping somebody may have a suggestion on marking it up.
This is something that I have not had to do before and would like to do it once and do it right if possible.
Any ideas out there???
 

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shortbus

Joined Sep 30, 2009
10,049
It's unclear in you first pictures of the sheet metal , but are you using the actual center of the shaft as your base line for the protractor? Also I wouldn't get too over complicate with marking every single degree on the final piece. Every 5 or so degrees should be good. This is because you will get spring back and need in actual use to adjust past most desired bends to get the correct results.

On the one I made for my bender I just have a clamp that is used for repeat bends and degrees marked only on the 45 -22 1/2 and 90 points. Tube bends aren't really that precise for one off bends.
 

Thread Starter

fiftyv8

Joined Jan 29, 2018
223
Shortbus, yes running from the true center, the square cut out is to clear the bearing block body hidden below the turntable.
I'm just running with what I can get my hands on in the hope that it reduces my work load, as everything I touch on this project is a job within a job.

I have found a circular steel drop out from my laser cutting shop which is 3" thick steel plate cut round that is 8" diameter, it weighs about 45lbs.

I have plans of turning this into my 2" tube bending form, but have no exact idea about what radius it should be to get a nice tight bend in 2" tube without asking for more than 2" tube can give...
Any thoughts amigo...
 
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