FAQ

Is there a difference between Tube and Pipe?
Yes. OD tube is measured by its exact outside diameter. For example, 1″ OD Tube is exactly 1″ across. Pipe, on the other hand, is measured by its inside diameter, but the actual measurement may be slightly more or less than stated. For example, 1″ Pipe may be more or less than a 1″ inside diameter. When ordering dies, it’s important to know if you’ll be bending pipe or tube. Tube dies will not bend pipe and vice versa. The proper die for your stock will eliminate possible problems or delays in your job. If you are not sure what you have, please send us a sample. We’ll be happy to help determine what you need.

What is minimum wall or wall gauge for Tube?
OD Tube comes in many different wall gauges. The Hossfeld Bender will bend .049″ thru .134″ depending on the diameter of the tube and radius you wish to bend.

What is Schedule 40 Pipe?
Pipe comes in wall thickness called schedules. The HOSSFELD UNIVERSAL(R) Bender bends Schedule 40 without difficulty. It’s possible to bend lighter schedule depending on the size of pipe and radius you wish to bend. We may ask for samples of your Pipe stock to ensure our dies can bend it to your satisfaction.

What is American Pipe?
American Pipe refers to American-made vs foreign-made pipe. Foreign pipe may not produce the results you want. American pipe specifications allow pipe to be bent. Foreign pipe specs are not as stringent. We commonly find two problems: the specifications for pipe sizes are not as strict, and the pipe may not even bend. What we find is that foreign pipe often has a bigger OD and does not fit into our dies properly. If you’re using foreign pipe, we may be able to make our dies fit the pipe; return the die to us with a piece of sample pipe, and we will try to custom-fit the die. Unfortunately, if the foreign pipe does not bend, we can’t alter the pipe’s characteristics. For the best results, always make sure you use American-made pipe.

Can I bend hot stock in the bender? Will it wreck my tooling?
Small quantities of parts can be bent hot on the HOSSFELD UNIVERSAL(R) Bender. The bender is designed to bend stock cold, however there may be times when stock will bend easier if it’s hot. Small quantities of parts may be bent hot on the bender. However, the bender pins and frames are heat treated, so it’s important NOT to remove the temper from them. Our cast iron dies will stand up better to hot parts, but long runs may take their toll on your dies.

Can I bend aluminum?
Yes, although the hardness of your aluminum will come into play. T4 is usually the best for bending. T6 may be bent but not to smaller radii, because the stock is brittle and will break. In addition, T6 doesn’t stretch, and tube must be able to stretch when it bends. We will gladly make sample bends and return them to you before your purchase for your inspection and approval. We can usually reduce scratching and marring of your stock by the die, if you let us know you will be bending aluminum.

Can I bend chrome-molly tube?
Yes. But you will need to stick to the recommended minimum wall thickness for the particular die set. If the die set calls for .095″ wall, that’s what you should use. With steel tube, you can sometimes deviate slightly from the recommended wall thickness. But with chrome-molly, you cannot. Minimum wall thickness is listed in the parts catalog for each die set.

How much tubing will I use up when I make my bend?
Good question. Here’s an easy formula to remember:

RADIUS X 6.28 X BENDING ANGLE / 360″
For example, to calculate the amount of tube used to bend 90º with an 8″ radius:
8″ X 6.28 X 90º / 360º = 12.56″ of tube from start to finish of bend

Using the trigonometry of a circle, here’s why the formula works:
To calculate the amount of tube you will use in a bend, start with the formula for the circumference of a circle: 2πr. π = 3.14, and the radius of the circle, r, is the radius you want to bend. Your tube will bend in an arc along a portion of this imaginary circle. Once you know the circumference of the circle, you can figure how much tube you will use with your degree of bend. First divide the degree of bend by 360 to get a ratio: degree_of_bend / 360. Then multiply the total circumference of the circle by that ratio.

Formula: (2πr) x (degree of bend / 360)
Example (same as above):
(8″ X 2 X 3.14) X (90º / 360º) = 12.56″ of tube

What is springback?
Trade items such as Pipe, Tube, Bar, etc. produced from Steel, Iron, Copper, Brass, Aluminum, or other ductile metals have been hardened by some combination of cold drawing and alloying with other chemical elements to give the stock the qualities of strength and elasticity. Elastic materials in general, when bent, will return to their original condition when released. However, if metal is bent beyond its elastic limit, it will tend to retain the form of the bend. During the bending of stock, the material in the OUTSIDE radius of the bend will be progressively stretched beyond its elastic limit (stressed in tension). The material in the INSIDE radius of the bend will be progressively compressed beyond its elastic limit (stressed in compression). Although these tension and compression stresses are opposite in effect, they never end up being equal in force. The difference between the forces of stress in the inside and outside of a bend is the cause of spring-back.

There is a small hump in my tube at the end of the bend. Why?
When you bend, the material stretches, and the diameter will decrease slightly. At the end of the bend, the stock will remain its original diameter. This mostly happens when you bend large diameter tube to a smaller radius. If this is undesirable, limit bends of large stock to larger radii, although the effect may still appear. In softer alloys, this can be even more prevalent.

I have a 1-1/4″ OD X 4″ CLR die set. Can I buy a 4-1/2″ CLR form die and use the backing blocks from the 4″ set?
No. Each radius die set is a matched three-piece set. The hole locations are different, and the hole numbers may be different, between sets. Parts are not interchangeable, although parts from different sets may occasionally fit together. We recommend you wire the sets together or paint them the same color to avoid mixing them up. If they do get mixed up, call us for technical support, and we’ll try to help you get them straightened out.

I purchased an OD Tube die set. When I fit my tube into the die to start a bend, it doesn’t seem to fit. Why?
Your die is working properly. The die openings are designed to be slightly smaller than the stock. The stock will be forced into the dies when pressure is applied and will grip the stock securely (this is known as pinch).

I purchased a Pipe die set. When I put all three pieces in the bender I can’t get the pipe to go in the die. Why?
Good question. The dies are made to fit tightly. What you need to do is remove your draw block and be sure it’s greased. Then place your pipe between the horn or straight side of the form die and the back block. A slight clockwise twist will lock your pipe into place in the back block. Then insert your greased draw block into the proper position, and the pin should drop in easily. You should be ready to bend. The pins should be able to be pushed in their proper holes easily. The pins or the pipe should not have to be hammered in place. When bending pipe sometimes you get foreign pipe, which for some reason is larger in size than American, and the dies don’t fit. In this case, we need to get the die back here with a sample of your pipe, and we can usually make things work. In severe cases we will have to re-work the whole die set.

I just put my 50B Outbend Angle Iron Master Die in the bender, but it doesn’t move. What’s wrong?
You’ve probably put the 19B U-Pin thru the main frame, swinging frame, and 50B Master Die together. You need to mount the Master Die with the 53B Wrist Pin in-between the swinging frame bars only. Mount the 50B at the second 3/4″ hole in the swinging frame by slipping the 53B Wrist Pin through the bottom. Once installed, the 53B Pin will be held in place by the main frame bars. See pages 18 & 19 in the Instruction Manual for more instructions and a diagram. This will allow the 50B to move.

I want to make a 90º bend. What radius size do I need?
90º is the degree to which you want to bend your stock — a right angle. We also need to know the radius of the bend. Bending to a small radius will use less stock. Bending to a large radius will use more stock. When we ask about the radius of the bend, we need to know how large you want to make that 90º bend. For example, 180º 1″ OD Tube Dies come in 2-1/4″ thru 8″ center line radius (measured from the center of the circle to the center of the stock). To bend more than 180º, Feed-Along 1″ OD Tube Dies are available for radii above 8″. They’ll all bend you stock to 90º but, depending on the radius, will bend a smaller or larger arc. The wall thickness of the stock will also determine the radius you can bend.

I have a 2″ OD X 6″ CLR die set. I dropped my draw block, and it broke. Can I get a replacement block?
Replacement parts are available for any die set. Just tell us the size and radius of your die set. Call us for availability and cost.

I want to bend 1-1/4″ Pipe to a 50″ radius. I see you don’t have a 50″ radius die set. Is it possible to do this?
Yes, you can bend larger radii on all of our feed-along dies — don’t pull the swing frame all the way forward until it meets the form die. For example, to bend a 50″ radius, buy the 36″ radius die. Use a template for a 50″ radius: another piece of pipe bent to the same radius, etc. Position it over the form die, and set the circle stop gauge on the bender main frame circle to stop the swing arm at that point. When you pull just to the stop, you will have a 50″ radius. Pick a radius form die close in size to the one you want to bend. For example, don’t use a 7-1/2″ die to bend a 200″ radius — it would be too hard to control how much to move the pipe through the die in order not to have flat spots in your radius. Also, it’s only possible to do this with the feed-along method of bending.

My back block has a number stamped on it. My draw block has TOP and a number stamped on it. What does this mean?
Those numbers are the holes the pins go in to install your die in the bender. For example, in a 1-1/4″ OD X 4-1/2″ CLR die set the blocks are stamped 5 and TOP 5. The back block goes in the 5th hole of the bender main frame. There is also a 1/4″ elevation pin in the bottom of the block. This rests on the main frame bottom bar and is there to help line up the grooves. The draw block has TOP 5 stamped on it. Put the die in with TOP facing upwards; if you put it in upside down, it won’t work correctly. The draw block also goes in the 5th hole of the swing frame with the 1/4″ elevation pin resting on the bottom bar. Remember, when installing dies in the bender only count the 3/4″ or 5/8″ holes depending on which bender you have, the No. 1 or No. 2

I recently purchased a bender from one of your competitors. They said their bender uses “Hossfeld” dies. I broke the draw block I bought from you for use with this other bender. Will you stand behind it?
HOSSFELD UNIVERSAL(R) dies are designed to be used only with Hossfeld authorized equipment. The only equipment authorized for this is HOSSFELD UNIVERSAL(R) bending equipment. Our policy states: “HOSSFELD UNIVERSAL(R) parts and dies are designed to be used with HOSSFELD UNIVERSAL(R) Benders. Use of other benders with HOSSFELD UNIVERSAL(R) parts and dies may cause inferior performance or lead to breakage of such parts or dies.” You will get the best performance from our dies with genuine Hossfeld equipment.

The back block in 1-1/2″ OD X 6″ CLR tube die set has no pin hole for the U-Pin to go thru, but it has a bolt and washer. Why?
In our larger size die sets, there’s a lack of space to fit a pin hole in the back block. We use what’s known as a “bolt-on back block”. This back block bolts to the 12B Oscillating Block, which comes factory installed with your bender. The 12B Oscillating Block has a flat side with a horizontal hole. Place your back block against the flat side with the TOP stamp facing up, and slide the bolt through the horizontal hole, then finger tighten the bolt. Insert your tube between the form die and back block, and tighten the bolt with a wrench. Grease your draw block, drop it in place, and you should be ready to bend.

How can I tell where my bend starts on my 180º die set?
Along the horn, or straight side, of the form die there should be a small mark either raised or stamped. This is your point-of-bend mark or where the bend starts.

What kind of oil do I put in my hydraulic pump and how much?
We recommend a good grade of hydraulic oil. A 20 viscosity would work fine. If that is not available, a good grade of SAE #10 non-detergent oil can be used, but it’s preferable to use hydraulic oil. The tank holds 10 liters of oil. Whenever you fill the reservoir, run the cylinder in and out three times to prep it. You may need to add a little more oil, but don’t fill the tank up again, because it will overflow when oil pumps out of the cylinder during the bending process. If the cylinder doesn’t move easily, or the pump strains to work, you probably need to add a little more oil.

How many bends can I make with a die set before it wears out?
It depends on what metal alloy you’re bending. Bending hard alloys will take its toll on your draw block. We publish our metal alloy capabilities in our catalog; others alloys can be bent, but this may affect the life of your die. Greasing the draw block will also help minimize friction and wear on the main moving component of a die set. Draw blocks need to be greased before every bend. This will give you longer die life and help in the performance of the die set. With proper care, hundreds if not thousands of bends can be made on a die set.

Why do I need to grease the draw blocks?
Greasing the draw block before every bend minimizes friction and wear on the draw block — the moving part of a die set. We recommend any good wheel-bearing grease. If you don’t grease the draw block, the cast iron material of the block will heat up and bond to your tube as it’s bending. This creates galling of the wear surface of the block, which will then gall the tube.