with an emt bender you can use the star for a back to back bend and not have to use the deduct method. How do you do that with the 555 if there is not enough conduit to travel throught the rollers for a back to back. I want to turn the pipe around and pull up on short end but still have my back to back turn out. No one I ask seems to be able to answer. there is no star on the sidewinder. Any help here. What do I add or subtract if I know where i want the back of my 90 is? Thanks.
greenlee 555 sidewinder
- Thread starter gbilger
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Measure how much gets "drawn in" across the roller, make a note of it per size pipe,etc. You can interpolate reasonably to - if 6" were to equal a 90, the 3" inches drawn in would be a 45, and 2" would equal 30. It takes a little time, but make friends with your triple nickel - one of the best friends the industry has!
RETRAINDAILY
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I would figure out how big the last 90 should be.
What is left of the pipe, plus your gain.
and mark and bend your short 90
What is left of the pipe, plus your gain.
and mark and bend your short 90
You will have to experiment a little.
Bend a 90 on the end of a full length of pipe with the hook at the end.
Then measure the length of the pipe to the back of the new bent 90.
The difference is the measurement that you will nave to add for a back to back bend.
You need have to have the hook in the same spot for each bend because their is no star.
Then mark the add measurement on the shoe with a sharpie for next time.
Bend a 90 on the end of a full length of pipe with the hook at the end.
Then measure the length of the pipe to the back of the new bent 90.
The difference is the measurement that you will nave to add for a back to back bend.
You need have to have the hook in the same spot for each bend because their is no star.
Then mark the add measurement on the shoe with a sharpie for next time.
What needs determined is the "gain". Bend a 90 on a full or pre-measured partial stick. Measure the two legs after bending, add together, then subtract pre-bend length. The result is the gain though a 90? bend.
For a reverse bend, measure distance from tail end. Mark on the stick where the "back" of the bend will be located after the bend, subtract the 90? gain amount, then add your normal 90? deduct amount... or you can do the math beforehand.
Your way works fine. Essentially the same, only you did some of the math physically
My explanation just elaborates on it using typical trade terminology and method.
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tryinghard
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cadpoint
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- Durham, NC
I've seen the sharpie marks : )> before, but sometimes there's multi marks!
I've never heard of it as "GAIN", But if correct as a term in this usage it's then should also be a reflection of the angular value that is obtainable and equatible...
Is the GAIN reflective of the numbers one uses off the charts on the 555 ?
I frankly thought those where something else!
K8MHZ
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- Electrician
K8MHZ
Senior Member
- Occupation
- Electrician
It's not that complicated.
Because of the bend, less pipe is needed to travel the combination of the two distances. For instance, if you had to go east 10 inches and then north 10 inches you would need less than 20 inches of pipe to do it. The difference between the two is what we call the gain.
cadpoint
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- Durham, NC
I'd bend on offset and include enough for the angle of rotation or the differnece to make it up the angle, but this not the point of this thread.
I'm sorry the use of this term is desciptive IMO, Gain reflects more to Radio usage, not angles and bends on first glance in the search engines...
Gain is also used in the "bending game". "Gain" is the proper vernacular terminology - Greenlee used to put out a booklet(assume they still do) called Conduit Bending Handbook. Mine is a 1990 edition, but let me tell you, it's solid gold for information right down to how much gain is increased for every degree!
Greenlee defines "Gain" this way - Because pipe bends in a radius and not at right angles, the length of pipe needed for a bend will not equalthe total length. Gain is the difference between the right angle distances A & B and the shorter distance C -- The length of pipe actually needed for th bend.
Gain Formula for 90 degree bends = 2 x radius -developed length or radius radius of bend x .43
See page 29 for any degree of of bend.
Just like ol' George Hart says - "Both time and energy will be saved if conduit can be cut, reamed and threaded before bending.
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K8MHZ
Senior Member
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- Electrician
As a licensed radio operator I see what you mean....in fact, the next time I express gain in pipe I am going to do it in dB.
Trade lingo and engineering terms don't always mesh perfectly.
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K8MHZ
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- Electrician
I have the Electrician's Guide to Conduit Bending and I love it.
http://www.coxco.net/Conduit_pipe_Bending_Book_p/b0010.htm
cadpoint
Senior Member
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- Durham, NC
As said never heard it, never seen it, but I might have read it off a chart and not understood it as such!
Thanks to the insight!
I have 2 Greenlee Conduit Bending Handbooks with 2003 copyright. Thought I lost the first so I got a second and later found the first. It is still listed in the bending catalog: #38405.
Also, the following image was clipped from the 555 manual...
I was pretty lucky when I was an apprentice, and got hooked up with some old guys, that taught me a lot. All I can do is hope to pass it on through to the next generation. Got five more years till I can pull the pin. No sense keeping knowledge locked up!
Gain is not on any chart (table) decal on the 555 itself, and none in the manual, though it is defined there.As said never heard it, never seen it, but I might have read it off a chart and not understood it as such!
Thanks to the insight!
Simple math will yield the "radius ? .43 = 90? gain" formula.
2 ? radius is straight-line distance
2 ? radius ? pi ? 4 is radial distance
The difference ("gain"):2 ? radius ? pi ? 4 is radial distance
2 ? radius ? 2 ? radius ? pi ? 4 = 90? gain
2 ? radius ? (1 ? pi ? 4) = 90? gain
2 ? radius ? 0.21460 = 90? gain
radius ? 0.42920 = 90? gain
2 ? radius ? (1 ? pi ? 4) = 90? gain
2 ? radius ? 0.21460 = 90? gain
radius ? 0.42920 = 90? gain
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