[epineh]

Thanks bigz1

John, I thought of doing that, I don't know how well it would hold up to the flexing, guess for the amount it will be doing it might be ok. The webbing is quite easy to glue on, just needs a bit of pressure to take.

I could also cut the duct as you had mentioned, leaving the bottom to act as a hinge. Hmmm more things to try. The upside is that I am only using scrap so far, so I can experiment with this a fair bit.

Russell.

[greybeard]

I'll probably use this method when I get that far on my own set up, and it occurs to me that to mend a split piece I'd use a strong self adhesive tape.
In which case it would seem sensible to try that right from the start !
I'd just have to identify the strongest adhesive for the duct that I intend to use. With the 'chain' turning inwards, the tape will not be trying to peel off, so this should make the demands on the adhesive less. Just turn the ends over into the inside of the first and last link should make it pretty secure.
To 'flash it up' - how about "chrome spray" from the nearest auto shop - I found it sits well on most plastics, especially if you give it a coat of spray varnish afterwards.

John

[nuplowboy]

I just upgraded the steppers and controller on my router and went with some approx 1/2" ID clear vinyl tubing I had lying around for another project. So far it seems to work great for keeping the wires in check, a couple screws and/or duct tape secured the ends (couldn't find my zipties at the time)

[greybeard]

epineh - I've been thinking(always dangerous) about which way to cut the trunking.
If you cut through just the U-shaped part, leaving the top off, then you can set up the saw to chop it into short lengths, with the ends at 5 degrees.
Then modifying the top, if necessary, is a seperate job.
However, if you cut through the top and the upper walls of the trunk, leaving the bottom as a hinge, you then have a long 'snake' flopping about, while you're trying to do the cutting.
Whereas handling the top piece on its own might prove easier, as it's not going to change much by nicking through part of its depth.

John

[epineh]

Hmm it would be nice to have some sort of computer controlled router thingy to cut these parts out...(chair) lol

The biggest problem as I see it is that the chain has to support itself two ways, one as Joe has drawn it, the 5 degree angle cut so it doesn't bend in on itself (like mine does at the moment) and also to hold itself together when the "top" section floats at the other end of travel and not droop down and "snake" as John puts it. At the moment my chain will support itself from one end easily, but it bends in too easy so the radius caves in under the top section's weight, as it gains size.

If I was to leave the chain as it is and put in a piece of something like a paper-clip shaped wire, with pins attached to the seperator divider, allowing it to open as it does now, but only a small amount, then it should work.

OK so I am rambling on now, I will try that, and also your ideas John, not now, just got the kids to sleep...

I like the idea of painting it when finished, reckon a coat of matte black would make it look like the bought stuff.

Russell.

[greybeard]

Mine will have an electric blue go-faster stripe along it
Just re-read your post, and see the problem with it drooping when fully extended.
Must put thinking hat on.
J

[ger21]

The biggest problem as I see it is that the chain has to support itself two ways, one as Joe has drawn it, the 5 degree angle cut so it doesn't bend in on itself (like mine does at the moment) and also to hold itself together when the "top" section floats at the other end of travel and not droop down and "snake" as John puts it. At the moment my chain will support itself from one end easily, but it bends in too easy so the radius caves in under the top section's weight, as it gains size.

Correct. The commercial stuff only bends in one direction, and a limited amount in that direction.

[epineh]

Mine will have an electric blue go-faster stripe along it
Just re-read your post, and see the problem with it drooping when fully extended.
Must put thinking hat on.
J

Think you are on the wrong track, everyone knows that it will go faster if it is a red stripe ... lol :stickpoke

You could have the hinge point in the middle of the side/ends like the commercial stuff (what I've seen anyway) and possibly have better control over its movement, but that will add complexity with duct and the idea of this is to keep it simple, without the need for CNC machine to start with.

I had previously tried to make some with LDPE, with a middle hinge but couldnt get it happening, needed the router finished to make better parts, the old chicken and egg thing again.

Russell.

[greybeard]

Your reference to a middle hinge prompted this idea- but then it might be what you were thinking
The lid pieces(cut separately afterwards) prevent the hinge bending up, but the saw cut(width to suit) allows the trunking to bend down till the base prevents further movement.
John

ps surely red is for gas go faster and blue is electric (chair)

[Geof]

If you can get hold of it without buying a full sheet try a strip of polycarbonate, 1/8" or 3/16" in place of the webbing. It flexes very nicely but has enough stiffness that it will not sag.

[epineh]

Lol I had to look again at your drawing twice John, it was early for me (any excuse!). At first glance I thought you had drawn a plan view with the lid and base shown as cut away views, couldn't work out how on earth that would work, what can I say, I confuse easily...

What you have drawn is pretty much what I meant by a middle hinge, only I was going to make a seperate hinge to bolt on. I could easily try your method, and I have a perfect way of testing for hinge life - a two year old daughter and a four year old son... expected operational life = time with kids (measured in minutes) multiplied by 30 (days in a month) should give roughly how many months the chain would last

Of course there may need to be a scaling factor if the kids have snuck into the cupboard and helped themselves to the red cordial.

Geof I was thinking of something along those lines, using another piece of the lid with the sides cut away to form a strip to act as the hinge/backbone, getting something already flat certainly seems easier than cutting up more lid.


Russell.

[greybeard]

I think this is going to be my best throw. I hope the drawing is self explanatory.

John

[epineh]

Ha, now we are getting somewhere, bout time duct tape came in and saved the day !!!

[greybeard]

This time it's for those who can't find the duct tape

The idea, though not accurately drawn, is for all the pieces to be identical, but each alternate piece is reversed, back to front.

The longer face goes inside the clip-on top, so that the vertical movement is restricted, one way it can rotate, but the`other way it locks.

John

[Geof]

This time it's for those who can't find the duct tape

The idea, though not accurately drawn, is for all the pieces to be identical, but each alternate piece is reversed, back to front.

The longer face goes inside the clip-on top, so that the vertical movement is restricted, one way it can rotate, but the`other way it locks.

John

You are getting dangerously close to what is commercially available; that's cheating .

Next thing you will suggest using 3" diameter vacuum cleaner hose which is what Haas use on the Mini Mills. Or it should say it looks like it.

[greybeard]

Ah, but mine will be sprayed chrome, with an electric blue go-faster stripe

I suppose convergent design is inevitable even if unknowing.

John

[epineh]

I still think that the red stripe would be faster

I think if you improve the chain any more you had better put a patent pending on it lol

Looks like I might have to go looking for some small plastic bolts. I know normal steel ones will be easier to find, but might as well keep it plastic.

Good work.

Russell.

[greybeard]

Thanks Russell, and OK, I bow to your greater experience of the optical frequency/velocity ratio controversy.
Regards
John

[epineh]

Thanks Russell, and OK, I bow to your greater experience of the optical frequency/velocity ratio controversy.
Regards
John

So you admit that red would be faster then ?

Russell.

[greybeard]

I'm prepared to accept a position of aquiescence, until experimental verification is able to provide unequivocal evidence to the contrary.
I propose to paint the top stripe blue and the lower stripe red and then see which way it curves.
("heh,heh,heh....he'll never spot the plot, Moriarty")

John