If you are using any tube/pipe bender and having issues with bend quality and deformation, you have come to the right place. We will help you learn how to measure and calculate your bend quality, and also how you can improve the bend quality you are getting on your M600 Mandrel Tubing Bender (standard or Mandrel). You will need calipers to perform these measurements.
Bend Quality Defects:
What causes them- D ratio too low, wall ratio too high, clamp block slipping, machine set up wrong.
What causes it- D ratio too low, wall ratio too high, clamp block slipping, machine set up wrong.
Bump at Bend Start
What causes it- D ratio too low, wall ratio too high.
What causes it- D ratio too low, wall ratio too high, or mandrel too far forward on mandrel applications. This is much more common on aluminum. Some materials are more prone to cracking, like aluminum. Some materials are more prone to wrinkling, such as copper and stainless steel. Materials that tend to bend well include Docol R8, 4130 Chromoly, Carbon steel, and Sandvik 2507 Duplex Stainless.
D Ratio Too Low
Wall Ratio Too High
Machine Set Up Wrong
Including full operation instructions here is not practical, but we will tell you the most common set up mistake made that affects bend quality is using a pressure die in the back of the machine (this hole is labeled “HD, never use on .120 wall or thinner”). If you are mandrel bending, the most common set up problem is mandrel position. Getting the perfect mandrel position will be the result of running several test bends with recordings of achieved bend quality and mandrel position used.
Clamp Block Slipping
The clamp block usually slides when it is clamped on dirty/oily material, or If your material kinks/wrinkles. Kinks can cause the clamp block to slide when the material binds up in the machine. The clamp block slipping can also cause wrinkles, so it can be either a cause or a symptom. The solution is simple. If your clamp block has grooves/scratches from sliding, they must be removed. Recondition the surface with 220 grit sandpaper or emery cloth, rubbing the same way twisting the tube would rub the surface. Only a few light passes until the offending slip lines are gone (no more). Now clean it with laquer thinner or acetone and a clean rag. Do not use any other cleaner. Clean your tubing at the clamp location the same way. We know this is extra work. Doing things right usually is. Now follow the clamping instructions, keeping bolt torque even. Remember that sliding oily tubing through your clamp blocks not only scratches them, but fills in those scratches with oil. Clamp blocks are extremely affordable, so keep that in mind for spares and/or replacements. We have not yet seen an application (even with the added drag from a mandrel) where one clean clamp was not enough clamping force.
Bend Quality Examples:
What Looks “Good”?
3% and less Deformation:
5% – 7% Deformation:
7% – 9% Deformation:
9% – 11% Deformation:
Common Applications and Average Deformation:
1.00 x .120 on a 3.5/4.5 CLR – Usually below 5%
1.25 x .120 on 4.5 CLR – usually below 5%
1.50 x .120 on 4.5 CLR – 6%
1.50 x .083 on 6.0 CLR – 7%
1.625 x .095 on 6.0 CLR – 7%
1.625 x .083 on 6.0 CLR – 10.5%
1.625 x .083 on 4.5 or 6.0 CLR w/Mandrel- 2.5%
1.75 x .120 on 4.5 CLR – 10%
1.75 x .120 on 6.0 CLR – 7%
1.75 x .095 on 6.0 CLR – 10%
1.75 x .095 on 4.5 or 6.0 CLR w/Mandrel- 2.5%
2.00 x .120 on 6.0 CLR – 10.5%
2.00 x .120 on 4.5 or 6.0 CLR w/Mandrel- 1.0%
If you are bending for paying customers, the best thing to do is keep sample bends of each material/CLR you bend (or a similar completed project/build). Show them to your customers who bring up bend quality before they put a deposit on fabrication work. This eliminates surprises. To open up the door for higher revenue, buy one mandrel bend from us in 1.625x.083 4130 or another material you use, and keep that bend in your shop for sales purposes. When relevant, show the mandrel and non-mandrel bends and explain that the mandrel bends are more expensive to produce. If you get a deposit on that level of work, order your mandrel conversion for your Rogue Fab M600 and enjoy the new capacity.
My buddy’s bends look WAY better, what gives?:
Most of the tubing bender companies we compete with will not discuss/estimate bend quality with their customers. We don’t like our customers to be surprised, which is why this page exists.
Compare the same CLR
Non-Round Bending Dies