Forum's Ugliest Winder. . . Almost complete

[kayakerca]

After working away at my SketchUp skills a bit and following Brad's tutoring, here is the CAM shape I came up with for a 7/16" bobbin (2 1/4" tip to tip and side to side). Won't have time to cut the CAM itself until next week.

[RedHouse]

Ok, I edited the post for you David.

... I don't see any significant difference between your time graph and my string unwinding trick...

That's ok.

[RedHouse]

...That is the same technique I tried in my CAM #4 (see post 34 in this thread)...

Now see when I read post 34, I understood your post as doing the opposite, having an existing cam and trying to reconcile it's shape to a graphic, sorry, my mistake.

The "design" method is to start with the desired pattern (ie; cam-profiles.jpg) and develop the actual part from there. It is also the way to get your desired travel for the cam profile you need.

After working away at my SketchUp skills a bit and following Brads tutoring, here is the CAM shape I came up with for a 7/16" bobbin (2 1/4" tip to tip and side to side). Won't have time to cut the CAM itself until next week.

That looks right to me, but what do I know.

Oh and BTW, just to be clear I like David he's a good guy, I just like to rib-him a little bit as we go along. If we were all drinking in a Pub, I'd be sitting at the same table as him. I think there would be more fun and hoop'la going on there than elsewhere.

[kayakerca]

Now see when I read post 34, I understood your post as doing the opposite, having an existing cam and trying to recocile it's shape to a piece of paper.

I used a CAM shape to start because it was easier to put the next pin prick in the shape from the travel points when it was already closer to the edge of the piece of CAM shaped paper. If I had 4 sets of hands it would have been a lot easier!

That looks right to me, but what do I know.

Oh, like a any number of people here, I think you know a ton! Thanks again Brad, I'll toss a couple back in your and David's honour when I get this CAM up and running next week.

[Chris Turner]

...Duplicate...

[Chris Turner]

Still "less than perfectly correct" David.




That's because that's not the way to design a cam profile. If you want to design a cam profile you have to have a couple things in mind, the base circle, the displacement (travel) and what type of "profile" you're after.

[ATTACH=CONFIG]21135[/ATTACH]

In our case, you are after "Uniform Motion" (see Fig-a), then, to lay out your profile is actually easy, just get out a ruler or your favorite drawing software and follow the procedures in the second picture attached (sorry it's so pixellated)

[ATTACH=CONFIG]21136[/ATTACH]

First decide how many sections (degrees) you want to use, in the atached pic I chose 15° intervals, then decide on your displacement (travel) which is represented by the top and bottom lines in the horizontal scale (Fig A)

Draw your profile across the horizontal graph (Fig B), this represents 1/2 the diameter but never mind that right now. Then draw your base circle and conect the intersections of the horizontal graph to the circles in the cam degree graph (Fig C,D,E).

Then plot a location (ie; a dot) at each intersection there the circles intersect with the degree divisions in the cam degree graph (Fig F) , then conect the dots (Fig G)... it's really as simple as that. Then you can cut out the profile in whatever material you are using.

In my old Lollar based winder (v2.0)

[ATTACH=CONFIG]21138[/ATTACH]

when I got tired of hand-guiding the traverse I made this heart shaped cam which worked great;

http://www.classicamplification.net/...mMotionCam.MPG

and IMHO made some nice coils:

[ATTACH=CONFIG]21137[/ATTACH]

(the wire is actually nice and even and in a slight arc, the pic was taken with a close-up lens which skew's the look of it)




And that is a nice looking coil BTW.

So, what should the diameter of the base circle be? Twice the height of your bobbin? Also, is the width of the horizontal section supposed to be the length of travel on the traverse? If so, does that mean it should be 1/2" for a bobbin that's 1/2" high?

Sorry, I don't quite get it, obviously.

[kayakerca]

So, what should you start with for the size of the base circle? Is the diameter twice that of the height of the bobbin? And as for the sections of the profile, I think I understand that the height of each section is equal to the radius of the base circle, but what is the width of each section supposed to be?

Hi Chris:

Given that the theory behind Brad's post is sound (and I believe it definitely is) then the base circle size doesn't matter. Use one that best fits the CAM mount plate and setup you have on your winder. Also, the bigger the CAM, the less the impact on traverser travel of little "slips" when you are cutting out the CAM shape.

The more points you use on your CAM design layout, the smoother the curve will be when you cut out the shape. I redid the one I did last night and put 24 points on each side of the CAM is it was definitely smoother looking.

[Chris Turner]

Hi Chris:

Given that the theory behind Brad's post is sound (and I believe it definitely is) then the base circle size doesn't matter. Use one that best fits the CAM mount plate and setup you have on your winder. Also, the bigger the CAM, the less the impact on traverser travel of little "slips" when you are cutting out the CAM shape.

The more points you use on your CAM design layout, the smoother the curve will be when you cut out the shape. I redid the one I did last night and put 24 points on each side of the CAM is it was definitely smoother looking.

Thanks. I'm still foggy on the horizontal section, though...

Also, is the width of the horizontal section supposed to be the length of travel on the traverse? If so, does that mean it should be 1/2" for a bobbin that's 1/2" high?

[kayakerca]

Thanks. I'm still foggy on the horizontal section, though...

Hi Chris:

Because (as Brad said) you want a straight traverse, you can draw the CAM layout a little easier than the technique in the second image that Brad posted. You can decide on what size base circle you want to use and just add more circles outside that on the same centre equal to the number of segments (bisecting lines) you want to use. The more secgments, the smoother the CAM curve. You will add one circle for each segment you made you divided you base circle into. Each new circle will have a radius larger than the previous circle by an amount equal to the bobbin height divided by the number of segments you decided to use.

Say you want your base circle 2" in diameter, therefore the radius of the base circle is 1". Now assume your bobbin height is 1/2". If, as an example you decide10 segments (bisections of the original circle) is going to create a smooth enough curve for you CAM design, then each of the 10 successively larger circles (on the original circle's centre) will the the bobbin height (1/2") divided by the number of segments (10) larger in radius that each previous circle. In this case (1/2" bobbin height / 10 segments = .05" radius increase for each successive circle). When you finish drawing all the successive circles, the distance from the base circle to the outside of the last circle will be 1/2" (10 X .05"). After that, you just connect the dots, the first bisect of the circle from the first circle to the second bisect of the second circle and so on. I have attached an example that should make the above description make more sense and seem less cryptic ( I hope). The example attached is actually 12 bisects and additional circles, not 10, but the math is more obvious with 10. When complete, the inner "V" of the circle is on the edge of the base circle and the outer "V" is edge of the outer most circle added. So you can see that when you rotate the CAM on its centre that the distance the pushrod will travel on the traverse is the distance from the inner "V" to the outer "V", which is 1/2" in the case (the height of the bobbin).

You will definitely need some CAD sort of software. I used SketchUp (was a Google product until recently when it was sold to a company called Trimble) which is free and fairly easy to get the basics of.

Wow, that is one confusing, long winded explanation. . .

[kayakerca]

Well. . .

I cut a new delrin CAM based on Brad's mentoring and put it on the winder. I don't have any lacquered bobbins on hand to wind, so I just ran it against the DTI that I use to fine tune the traverse distance (basically finds centre as the CAM is cut for the 7/16" bobbin). Anyway, after watching the dial gauge move back and forth throughout the traverse distance a bunch of times, I can say that this is definitely the most constant linear speed I have seen on any of my previous CAM's. My guess is that any imperfections in the coils will only be a result of my clumsiness when I was sanding the CAM into shape. I am REALLY looking forward to doing some winding with this new CAM next week!

[David King]

Brad, I'm glad we can come to an agreement in the bar. I'm a string and pencil kind of guy. I'm glad everyone else is happy to do this in Sketchup or SolidWorks. I for one never mastered apple draw so I keep a lot of string and dowels in my cave.

[RedHouse]

...base circle size doesn't matter. Use one that best fits the CAM mount plate and setup you have on your winder. Also, the bigger the CAM, the less the impact on traverser travel of little "slips" when you are cutting out the CAM shape.

The more points you use on your CAM design layout, the smoother the curve will be when you cut out the shape...

Absolutely correct! you choose the base circle, the travel, and get a cam that fit's your need.

Brad, I'm glad we can come to an agreement in the bar. I'm a string and pencil kind of guy. I'm glad everyone else is happy to do this in Sketchup or SolidWorks. I for one never mastered apple draw so I keep a lot of string and dowels in my cave.

What happened? I thought in past threads you said you were a machinist of some sort, how do ya use string and pencils on a lathe or mill?
(ie; remember posting about making sleeves for shafts?)

Anyway, doesn't matter, I did my first one (Cam layout) with a pencil and ruler on graph paper, nothing wrong with that at all.

[kayakerca]

Well. . .

I cut a new delrin CAM based on Brad's mentoring and put it on the winder. I don't have any lacquered bobbins on hand to wind, so I just ran it against the DTI that I use to fine tune the traverse distance (basically finds centre as the CAM is cut for the 7/16" bobbin). Anyway, after watching the dial gauge move back and forth throughout the traverse distance a bunch of times, I can say that this is definitely the most constant linear speed I have seen on any of my previous CAM's. My guess is that any imperfections in the coils will only be a result of my clumsiness when I was sanding the CAM into shape. I am REALLY looking forward to doing some winding with this new CAM next week!

Well, Still not perfect out of the gate. . .

The concentric circle CAM design technique is still a little fast on the inward "V" end of the traverse and a fair bit slow on the outer "V" end. If I can speed up the pointed end of the heart shape properly, I think this could be a keeper. Thank goodness this is a great part of the fun of it all!

[big_teee]

So, I have been an innocent by stander taking in all the cam building.
Have a few elementry questions.
When you make this cam, are you locked in to bobbin height.
I vary my bobbin height greatly on different pickups.
Is the cam the mechanism that controls the traverse width?
Don't really understand the whole concept.
Please answer that question, then I will ask the others?
T

[RedHouse]

On mine, I prefer a slight bulge in the middle, not really flat like some people strive for.

So what I did on the Cam profile is (looking at the horizontal graph) made the first and second sector rise/fall faster. Instead of the linear diagonal ramp I sent my line up with a curve to it, then when the cam was cut it moves switfter when approaching the two ends causing less dwell there, and thereby getting a bit of a bulge in the center area.

Looking at your picture it looks to me like your physical cam is not centered in it's throw as one end of your coil looks fatter (base end) than the other (top end), like a centering issue.

On this old winder I had to mark the Cam's center of travel to make setup easier, I get the Cam to the center (which is the side of the heart-shape) then adjust the actual traverse linkage and mechanism.

As (Rewind) mentioned earlier, it's hard to get things "setup" specially when changing bobbin types, so here is some pics of what I did to make setup easy and fairly quick when using 1 cam for many bobbins.

Not saying it's the "best" way, it's just the way I did it on this old winder. This old winder was built and modified MANY times so things are kind of done "patchwork", nothing but the counter and speed control were there initially when I built it, everything else was added on in stages, not the way I would build one now days. My new winder is much sleeker.

Anyway the idea is to center the cam travel first by lining up the roller follower with the line I made when I drew the cam, then the adjust the traverse pivot base to center on the bobbin when it's mounted on the flange, finally the linkage can be adjusted to account for differernt size bobbins, badda-bing-badda-boom, problem solved.