lilscorpion
Well-known member
Saturday I built a tubing straightener to straighten out the roll of hard line (0.040 steel) that I purchased to fab the fuel lines in a project I've been working on. The concept was to build one for a fraction of the cost of one of the real ones. I found some rope pulleys at the hardware store which is what got me thinking.
They fit the tubing perfectly.
The pulleys use a steel bushing instead of bearings. Figured it would roll well enough.
The bushing was some freaky metric ID so I drilled it out to 3/8's (just a skim cut)
And reassembled the pulley using the vise on the vise
Then I machined a piece of aluminum 1/4" angle I had (about 10" in length) for the pulleys. Three holes and two slots.
Then made an adjustment bar for the slotted pulleys.
Then a little test fit.
Now I need a way to adjust the top pulleys. Used a smaller piece of angle and welded it to the top. Then drilled a hole for a set screw.
Didn't have one (lol) so I made one out of a bolt and turned the head on the lathe.
And put it I place..
Turned out cool. Materials on hand + $30. Not bad.
So tried it out. 8' of tubing. Ran it through maybe a couple dozen times. Did it straighten it?!? Sort of. It got fairly straight. The pic shown below is deceiving. Some of the bend is the weight of the tubing.
The wheels didn't roll well or even enough so the resistance caused some "tweaks" that I couldn't get out which probably made today's mess partially come to fruition. To make it work, in hind sight, the wheels need some roller bearings so it operates smoothly and allows the tubing to roll through with less effort. The wheels need to be further apart too. Maybe add a few inches to the over all length. The wheels need to have a shallower groove cut into them too. The pulleys offered too much resistance (though with roller bearings it may not matter. I may machine the wheels too so that the groove surface is smoother. The pulley wheels weren't exactly smooth. They were close but Since they're cast, they do have some subtitle imperfections.
So, basically, fail.
They fit the tubing perfectly.
The pulleys use a steel bushing instead of bearings. Figured it would roll well enough.
The bushing was some freaky metric ID so I drilled it out to 3/8's (just a skim cut)
And reassembled the pulley using the vise on the vise
Then I machined a piece of aluminum 1/4" angle I had (about 10" in length) for the pulleys. Three holes and two slots.
Then made an adjustment bar for the slotted pulleys.
Then a little test fit.
Now I need a way to adjust the top pulleys. Used a smaller piece of angle and welded it to the top. Then drilled a hole for a set screw.
Didn't have one (lol) so I made one out of a bolt and turned the head on the lathe.
And put it I place..
Turned out cool. Materials on hand + $30. Not bad.
So tried it out. 8' of tubing. Ran it through maybe a couple dozen times. Did it straighten it?!? Sort of. It got fairly straight. The pic shown below is deceiving. Some of the bend is the weight of the tubing.
The wheels didn't roll well or even enough so the resistance caused some "tweaks" that I couldn't get out which probably made today's mess partially come to fruition. To make it work, in hind sight, the wheels need some roller bearings so it operates smoothly and allows the tubing to roll through with less effort. The wheels need to be further apart too. Maybe add a few inches to the over all length. The wheels need to have a shallower groove cut into them too. The pulleys offered too much resistance (though with roller bearings it may not matter. I may machine the wheels too so that the groove surface is smoother. The pulley wheels weren't exactly smooth. They were close but Since they're cast, they do have some subtitle imperfections.
So, basically, fail.



I do have a small display shelf that holds cool pieces of scraped parts. To the unsuspecting eye, they me be nice parts, but really I missed a critical dimension and had to start over.
. For brake line I've found using a role of kunifer (cunifer) is way easier then using steel and priced between steel and stainless. It bends like copper and won't kink and is DOT approved sow no worries of safety.