? rolling strap for double helix
 

I want to build a trellis, the design of which was inspired by DNA's
double helix. Here's a picture from a gardening catalogue.

http://www.gardeners.com/estate-trel...efault,pd.html

I'll relate my failed efforts to build it; then my proposed solution.
Feedback appreciated.

I was feeling pretty smug; I happen to have a six foot PVC pipe,
eighteen inches in diameter, with 1/2 inch thick walls. Perfect for a
form for this project. I'm using 1/8 by one inch strap because it's
been gathering dust on my shelves for years. No amount of clamping to
the form got me anywhere close.

Then it was time to bring out the HF roller. I can roll eighteen inch
circles with it, but the coils won't stretch out properly.

Then I tried putting the strap through the roller at an angle-maybe 10
degrees from parallel with the roller ends. That angle put a lateral
force on the first roller that kept forcing the retainer to pop off.
The retainer clip is just that-a retainer clip-and not designed to
resist much pressure. I managed to get about 15 inches of strap
through the roller by replacing the roller and clip several times.
Wrong setup, but the 15 inches I got through the roller looks like I'm
thinking on the right track.

Looking at the picture, the strap appears to be at approx. a 45 degree
angle to the center post. So now I'm thinking I need to feed the
strap through the rollers at a 45 degree angle. In order to do that,
I'll need a roller that's four to six inches wide. I contacted
several local machine shops and all I got was a good luck pat on the
back. I've looked around the net and haven't seen one that would do
the job. I figure if they're that hard to find, if I did find one, it
would be out of my price range.

Now I'm considering building a roller. I'm thinking of modifying the
roller that Keith Marshall posted in the past week; I think it's a
very nice piece of work. I've already scrounged a lot of the iron,
but I'll have to pay for lathe work.

So, my question, before I invest the time and money, is my idea of
rolling the strap at an angle going to work?

Thanks,
Steve

? rolling strap for double helix
 

We used to roll the pipe helix for playground equipment by the hundreds
for a couple of the major playground equipment mfgs. We used a big
power roller but the secret was to do the first 3/4 of a turn, then tilt
the output so it rolled a spiral using a bar to keep the roll forming
correctly. It helps if the roll dies are fairly worn or oversized.

wrote:
I want to build a trellis, the design of which was inspired by DNA's
double helix. Here's a picture from a gardening catalogue.

http://www.gardeners.com/estate-trel...efault,pd.html

I'll relate my failed efforts to build it; then my proposed solution.
Feedback appreciated.

I was feeling pretty smug; I happen to have a six foot PVC pipe,
eighteen inches in diameter, with 1/2 inch thick walls. Perfect for a
form for this project. I'm using 1/8 by one inch strap because it's
been gathering dust on my shelves for years. No amount of clamping to
the form got me anywhere close.

Then it was time to bring out the HF roller. I can roll eighteen inch
circles with it, but the coils won't stretch out properly.

Then I tried putting the strap through the roller at an angle-maybe 10
degrees from parallel with the roller ends. That angle put a lateral
force on the first roller that kept forcing the retainer to pop off.
The retainer clip is just that-a retainer clip-and not designed to
resist much pressure. I managed to get about 15 inches of strap
through the roller by replacing the roller and clip several times.
Wrong setup, but the 15 inches I got through the roller looks like I'm
thinking on the right track.

Looking at the picture, the strap appears to be at approx. a 45 degree
angle to the center post. So now I'm thinking I need to feed the
strap through the rollers at a 45 degree angle. In order to do that,
I'll need a roller that's four to six inches wide. I contacted
several local machine shops and all I got was a good luck pat on the
back. I've looked around the net and haven't seen one that would do
the job. I figure if they're that hard to find, if I did find one, it
would be out of my price range.

Now I'm considering building a roller. I'm thinking of modifying the
roller that Keith Marshall posted in the past week; I think it's a
very nice piece of work. I've already scrounged a lot of the iron,
but I'll have to pay for lathe work.

So, my question, before I invest the time and money, is my idea of
rolling the strap at an angle going to work?

Thanks,
Steve

? rolling strap for double helix
 

wrote:
I want to build a trellis, the design of which was inspired by DNA's
double helix. Here's a picture from a gardening catalogue.

http://www.gardeners.com/estate-trel...efault,pd.html

I'll relate my failed efforts to build it; then my proposed solution.
Feedback appreciated.

I was feeling pretty smug; I happen to have a six foot PVC pipe,
eighteen inches in diameter, with 1/2 inch thick walls. Perfect for a
form for this project. I'm using 1/8 by one inch strap because it's
been gathering dust on my shelves for years. No amount of clamping to
the form got me anywhere close.

Then it was time to bring out the HF roller. I can roll eighteen inch
circles with it, but the coils won't stretch out properly.

Then I tried putting the strap through the roller at an angle-maybe 10
degrees from parallel with the roller ends. That angle put a lateral
force on the first roller that kept forcing the retainer to pop off.
The retainer clip is just that-a retainer clip-and not designed to
resist much pressure. I managed to get about 15 inches of strap
through the roller by replacing the roller and clip several times.
Wrong setup, but the 15 inches I got through the roller looks like I'm
thinking on the right track.

Looking at the picture, the strap appears to be at approx. a 45 degree
angle to the center post. So now I'm thinking I need to feed the
strap through the rollers at a 45 degree angle. In order to do that,
I'll need a roller that's four to six inches wide. I contacted
several local machine shops and all I got was a good luck pat on the
back. I've looked around the net and haven't seen one that would do
the job. I figure if they're that hard to find, if I did find one, it
would be out of my price range.

Now I'm considering building a roller. I'm thinking of modifying the
roller that Keith Marshall posted in the past week; I think it's a
very nice piece of work. I've already scrounged a lot of the iron,
but I'll have to pay for lathe work.

So, my question, before I invest the time and money, is my idea of
rolling the strap at an angle going to work?

Thanks,
Steve

Try the following.
Coil the strapping around your poly pipe the no of turns you want in
your helix.
Cut off to length.
Remove from pipe. lay on flat board or smooth ground/ concrete/tarmac.
Get someone to hold one end firmly. you take the other end and
stretch. You will find it will become the helix you desire for the
length you want.
Tyr it with some wire first.
Forfet rolling. It will go by itself. Report back your results.
Ted
Dorset
UK.

? rolling strap for double helix
 

On Apr 1, 3:29*am, wrote:

So, my question, before I invest the time and money, is my idea of
rolling the strap at an angle going to work?

Thanks,
Steve

Before you build another rolling machine, try rolling the strap so it
makes a spiral that is close wrapped. ie the coils touch each other.
Then stretch to make the spacing of the coils what you desire.


Dan

? rolling strap for double helix
 

They usually don't uncoil uniformly.

wrote:
On Apr 1, 3:29 am, wrote:

So, my question, before I invest the time and money, is my idea of
rolling the strap at an angle going to work?

Thanks,
Steve

Before you build another rolling machine, try rolling the strap so it
makes a spiral that is close wrapped. ie the coils touch each other.
Then stretch to make the spacing of the coils what you desire.


Dan

? rolling strap for double helix
 

" fired this volley in news:a96b9f3d-
:

Before you build another rolling machine, try rolling the strap so it
makes a spiral that is close wrapped. ie the coils touch each other.


Dan, how would you do that with a roller that had bearing bosses at both
ends? The spacing would _have_ to be at least as wide as the thickness
of the boss.

The only way I see achieving that end is with cantelevered rollers.

LLoyd

? rolling strap for double helix
 

On Tue, 31 Mar 2009 19:29:52 -0700,
wrote:

I want to build a trellis, the design of which was inspired by DNA's
double helix. Here's a picture from a gardening catalogue.

http://www.gardeners.com/estate-trel...efault,pd.html

I'll relate my failed efforts to build it; then my proposed solution.
Feedback appreciated.

I was feeling pretty smug; I happen to have a six foot PVC pipe,
eighteen inches in diameter, with 1/2 inch thick walls. Perfect for a
form for this project. I'm using 1/8 by one inch strap because it's
been gathering dust on my shelves for years. No amount of clamping to
the form got me anywhere close.

Then it was time to bring out the HF roller. I can roll eighteen inch
circles with it, but the coils won't stretch out properly.

Then I tried putting the strap through the roller at an angle-maybe 10
degrees from parallel with the roller ends. That angle put a lateral
force on the first roller that kept forcing the retainer to pop off.
The retainer clip is just that-a retainer clip-and not designed to
resist much pressure. I managed to get about 15 inches of strap
through the roller by replacing the roller and clip several times.
Wrong setup, but the 15 inches I got through the roller looks like I'm
thinking on the right track.

Looking at the picture, the strap appears to be at approx. a 45 degree
angle to the center post. So now I'm thinking I need to feed the
strap through the rollers at a 45 degree angle. In order to do that,
I'll need a roller that's four to six inches wide. I contacted
several local machine shops and all I got was a good luck pat on the
back. I've looked around the net and haven't seen one that would do
the job. I figure if they're that hard to find, if I did find one, it
would be out of my price range.

Now I'm considering building a roller. I'm thinking of modifying the
roller that Keith Marshall posted in the past week; I think it's a
very nice piece of work. I've already scrounged a lot of the iron,
but I'll have to pay for lathe work.

So, my question, before I invest the time and money, is my idea of
rolling the strap at an angle going to work?

Thanks,
Steve

See
http://members.goldengate.net/dforeman/roller/

Ring roller drawings and such
 

Steel outfits that manufacture tanks have long open ended rollers for
rolling the metal to make the tanks. Some culvert manufacturers roll a
spiral formed culvert. they would have the rollers to do the job.



..

? rolling strap for double helix
 

On Wed, 01 Apr 2009 10:00:21 -0500, Don Foreman
wrote:


So, my question, before I invest the time and money, is my idea of
rolling the strap at an angle going to work?

Thanks,
Steve

See
http://members.goldengate.net/dforeman/roller/



O.P. here.

Don,
I think your link confirms my ideas. I'm going ahead with my plans to
build a roller.

Like other posters who have replied, I couldn't visualize how strap
would behave differently than round rod in this situation. When I
wrapped the strap around the PVC pipe, 1 and 1/2 revolutions in six
feet, the strap would not lay flat against the pipe. One edge of the
strap would be touching the pipe; the other edge was 3/4 inch off the
pipe. It looked awful.

I think what needs to be done is form the strap in two directions at
once.. Through the thickness like rolling a ring, and across the flat
like creating a flat ring. I hope that makes sense. Anyhow, I'm going
to make a roller-nothing ventured, nothing learned.

Thanks,
Steve

? rolling strap for double helix
 

On Apr 1, 2:53*pm, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Dan, how would you do that with a roller that had bearing bosses at both
ends? *The spacing would _have_ to be at least as wide as the thickness
of the boss.

The only way I see achieving that end is with cantelevered rollers.

LLoyd

The original post said he was using a HF ring roller. The HF ring
roller has cantalevered rolls.

Dan

? rolling strap for double helix
 

On Apr 1, 2:53*pm, RoyJ wrote:
They usually don't uncoil uniformly.

Hmmmm. As I recall that is how Ernie says he makes banisters for
spiral staircases. Will have to see if I can find more information.

Dan