Alex- cool stuff. way less complicated than what I have at my site.

Richard Long
Temecula, CA
RICX

Our webmaster saw your post and forwarded it on to me. As the person at Swagelok now responsible for our tube bending training, I say “Bravo” to you for thinking up a method of bend layout that works for you.

Please allow me to point out that Swagelok offers two 1/4 in. hand benders; one with a 9/16 in. bend radius, and another with a 3/4 in. bend radius. The gain information provided in the manual reflects results observed using our benders. I can”t speak for the results achieved using our bend data with other bending equipment.

That said, I can suggest a few things that may help viewers of your blog with their bending projects (bends up to 90 degrees) regardless of the bender they are using:

1) Forget about gain. While it does have its purpose, it is usually more confusing than beneficial.

Make all bends with the reference end (the end of the tubing from where your first measurement originates) of the tubing to the LEFT of the tubing clamp. If you must make a “reverse bend” (a bend made with the reference end of the tubing to the right of the tube clamp), you will need to learn about gain.

2) Treat the marks on the roll support / slide (0, 45, L or 90) as you would a 0-90 scale. These marks indicate the tangent point for the angles 0, 45, and 90 (if the reference end of the tubing is placed to the LEFT of the tube clamp during bending).

Treat the R mark as a tangent point for a 60 degree angle. (by the way, yes, the R mark does have another purpose – but I”m not going there as discussing it brings up the subject of gain that I told you to forget about in step 1)

Scribe (or mark with ink) a line midway between the R and L (or 90 on some benders). This mark will indicate the tangent point for a 75 degree bend. Visually divide the area between 0 and 45 into thirds and scribe two marks to indicate tangent points for 15 and 30 degrees.

Example:
If you would like to make a 90 degree bend 2 in. from the end of the tube, make a mark at 2 in., place the mark under the L (or 90), and bend 90 degrees. The distance from the end of the tube to the centerline of the 90 degree angle will be 2 in.

Now, suppose a subsequent 45 degree bend is to be made 5 in. away from the vertex of the 90. Visually line up your ruler on the vertex of the 90 and make a mark 5 in. down the tubing. Line up this mark under the 45, make sure the bend is going to be made in the correct plane, and complete your bend.

If you had needed to make a 60 degree bend instead of a 45, you would have lined up the measurement mark under the R instead of the 45. Had it been a 30 degree bend, you would have used the mark you scribed between the 0 and 45 to indicate 30 degrees. 50 degrees? Line up the mark 1/3 the way between the 45 and R.

The drawback with this is that you must visually locate the vertex of the preceeding bend. It get’’s easier with experience, but it’’s not an exact method.

The biggest advantage is there is no math involved – and it works!

One last thing, I must caution you regarding the use of mathematical formulas. While I won”t argue that they work well for smaller tubing sizes, you will likely find that as the OD of the tubing you”re bending increases (1/2 in. and up), your results won”t always follow the formula. It’’s at this point that mistakes can get very expensive as well as frustrating. Believe me, I echo your desire to avoid wasting tubing (not to mention time).

I”ve recently developed a spreadsheet that provides bend data that accurately accounts for the variations from the theoretical values provided by the formulas.

Please use the following address to see data generated by this spreadsheet in our new Bench Top Tube Bender Users Manual (http://www.swagelok.com/downloads/webcatalogs/EN/MS-13-145.PDF)

In addition, I have also developed a system that allows you to use this bend data to accurately calculate the location for all measurement marks in a bend layout prior to making the first bend. It works for any bend angle up to 180 degrees in all tubing sizes supported by Swagelok benders. In limited testing it has worked for other equipment as well. I”ve used it to make layouts with as many as 14 bends. If you get into a bind, or begin bending larger tubing, please contact me.

Thanks, and good luck!

Mike Gagel
Swagelok Distributor Training Services