Introduction: Tubing Roller-Bender From Scratch

Hello again everyone! In this instructable, I will be showing you how to build a roller-bender machine from scratch. First, though, a little background on how this project came about: After reading reviews of the harbor freight tubing roller, I figured it would be good enough for what I needed, and it was only $200, so I bought one. The roller, of course, broke catastrophically the first time I tried to use it. Typical harbor freight. I attempted to fix it to my satisfaction, was thwarted by non-standard part and thread sizes (again, typical harbor freight), and after looking into buying a new one and finding that a good one would run me upwards of $1,000, (for just the roller, die sets are about $200 each for good ones) or more (up to around $5,000) if I wanted anything fancy, I decided to build my own from scratch. If you build just the roller, you can easily do it for around $300-400. If you own a lathe, you can make your own roller dies for about $25-50 a set depending on the size of the dies. My roller features multiple locations to place the bottom dies, allowing you to place them farther apart for larger radii, which in turn requires less effort to do the rolling. Other features include a jack to force the top die down and easily bend the tubing, guide bars and spacers to eliminate slop when rolling (slop is when a tube turns out all wonky because there was side-to-side motion in the roller dies while you were rolling), and bolts to securely fasten the roller to the table, among other things. I will also show you how to make your own dies, and I will update that section as I make more types of die sets. Let's get started!

Note: Since this was my first time building a tubing roller, and since I was sort of making up the design as I went along, I made a few mistakes which resulted in a few unnecessary holes, poorly placed holes, and stuff like that. I also made a lot of stuff out of order, and assembled stuff multiple times to check fit, even when I knew I would have to disassemble it again. In order to eliminate confusion, I have both taken pictures and made technical drawings of the various parts, when the technical drawings and pictures conflict, the dimensions and locations on the drawings always override those in the pictures. In other words, if a hole is off-center in a picture but the drawings show it in the exact center of a piece, don't drill the hole off-center. Also if a drawing shows, for example, more holes than a picture for a certain step, feel free to drill all the holes at the same time so that you don't have to disassemble stuff to drill the rest of the holes later.

Step 1: Materials and Tools List

For making the roller...


  • Circular saw
  • Miter saw
  • Negative rake saw blades for circular and miter saws (or normal blades that you don't care about destroying)
  • Reciprocating saw or Jigsaw with blade for non-ferrous metals
  • Drill Press with drill bits for metal (cobalt, HSS, etc.)
  • Taps
  • Right angle clamps (2 is enough)
  • Bi-Metal hole saws
  • Combination square
  • Hammer and center punch


  • 2 - 27" by 21" by 1/2" aluminum plate
  • 1 - 8" by 15" by 1" aluminum plate
  • 1 - 6' by 1" by 1/4" aluminum bar
  • 4 - large extension springs
  • 1 - bottle jack
  • 1 - 36" by 3/4" keyed shaft
  • 6 - flange block bearing (I used UCF204-12)
  • Various nuts, bolts, lock washers, and washers, sizes 1/4", 3/8", and 7/16"

For making die sets...


  • Metal Lathe
  • 4-Jaw lathe chuck
  • Lathe tooling for boring, facing, drilling, and other standard operations
  • Drill press or Vertical milling machine with tooling for drilling
  • Precision calipers (accurate to .001" is fine)
  • Various files
  • Basic knowledge of how to use a lathe without killing yourself


  • 3" or larger solid aluminum rod
  • shaft keys

Step 2: Don't Be Stupid

Seems pretty obvious to most of us, but I'm going to say it anyways. This project has the potential to seriously injure or kill you if you act like an idiot or don't know what you're doing. If you have never worked with metal before, this is probably not a good introductory project. If you have never used a lathe, don't try to make your own dies without help and supervision. If you are the kind of person who cuts corners and blatantly disregards their own safety, go somewhere else. Also, if you disregard my warnings and stupidly attempt to do this project even though you don't know what you're doing, I am not responsible for you cutting off fingers or killing yourself as a result. Now that we've gotten that out of the way, lets get building!

Step 3: Technical Drawings

Here are the technical drawings I have made which tell you dimensions and hole locations for each part. All measurements are in inches.

Step 4: Lay Out Side Pieces

We will be making the side pieces out of 1/2" aluminum plate. I chose aluminum over steel because it is both far lighter and easier to work with than steel, and it won't rust. It is also more expensive, but I believe the extra expense is worth it to have something that doesn't require 4 people just to lift it into your truck, and to allow it to be more accessible to people who don't have machine shops in their garage.

I recommend using a drywall square to ensure that you end up with right angles and straight lines. Also, it is important to make sure that both side pieces are as close to identical as possible, otherwise it will create problems later. I got my side pieces identical within about 1/64 of an inch, although 1/32 would be fine for the outline.

Step 5: Cut Outline of Side Pieces

First, you'll want to cut off any extra pieces so that you are left with a rectangle which lines up with the edges of your side pieces. Then, cut along the diagonals as shown in the second image. When cutting aluminum, move the saw forward more slowly than you would if you were cutting wood. The accuracy of these first cuts is not crucial, I didn't use a guide bar and just free handed mine and they turned out fine. Be sure to wear a face shield and gloves when cutting the aluminum, as the chips tend to fly everywhere and can be quite sharp.

Step 6: Cut Holes in Side Pieces (optional)

Now we need to cut out holes in the side pieces to reduce the weight of the machine (and because it looks cool). Feel free to skip this step if you don't intend to be moving your machine much or otherwise don't care about the weight. In order to make interior cuts with a circular saw, you have to do something called a plunge cut. There are special saws which are specifically made for plunge cutting, however even I wouldn't use it enough to justify the expense in buying one. Since the primary purpose of these cuts is to reduce weight, extreme precision is not required, and thus we can get away with using a standard handheld circular saw for our plunge cuts.

To make a plunge cut with a circular saw, first tip the saw forward until only the front of the base plate is resting on the workpiece, with the teeth at least an inch above the surface. Now start the saw, and line up the blade to make your cut without letting the teeth touch the workpiece. Very slowly, tilt the saw down and back until the blade makes contact with the workpiece, and continue slowly lowering the blade until it cuts all the way through the workpiece. Be sure not to twist the saw from side to side at all, or the blade can bind in the cut, mess things up, break teeth on the blade, throw the saw out of the cut, etc. Then cut (slowly) as you normally would until you finish the cut, let the blade come to a complete stop, and raise the saw out of the workpiece. You will be left with a small amount of uncut metal at the ends of each cut, finish these cuts with a jigsaw or reciprocating saw with the appropriate blade. I recommend practicing plunge cuts on some scrap plywood first if you have never done them before.

Step 7: Drill Holes for Side Shafts and Center Slides

Now drill 3 holes on each side of each side piece, each 1" in diameter. Use a drill press to ensure that the holes are drilled vertically. In addition, drill 2 holes in the center of each side piece, also 1" in diameter.

Step 8: Cut Out Center Slides

Now make 2 parallel cuts between the two center holes that you drilled in the previous step to make a slot for the center shaft to slide up and down in. You will need to make plunge cuts again.

Step 9: Drill Mounting Holes for Side Bearings

Now use the drill press with a 27/64 drill bit to drill 4 holes around each 1" hole which will be used to mount the side bearings. Try to be as accurate as possible with the locations of the holes to mount the bearings. The more accurate you are, the more precisely you will be able to bend your tubing.

Step 10: Cut Out Pieces for Center Slide

Now cut out pieces for the center slide. The side plates are made out of 1" plate, so you will have to make several passes with the saw. You will need to use a miter saw for this, as a handheld saw will not be accurate enough for the tolerances we need. Instead of spending $100 on a 12" negative rake sawblade, I just bought a new normal one for about $40 and used it, and it worked fine as long as I went slowly and didn't try to cut more than about 1/4" deep at a time. Make 2 side plates.

The top plate is 1/2" aluminum, and is a simple rectangle, however dimensions must be as close to exact as possible. Oversized, and it won't fit; undersized, and it won't work properly.

Step 11: Drill Holes in Center Slide Pieces

Now it's time to drill holes so that we can bolt together the pieces of the center slide. First, use a pair of right angle clamps to hold together the top piece and one of the side pieces as shown in the second image. Be sure to line up the edges very precisely. Mark and punch the locations of the first 3 holes. Then, use a vise to clamp the pieces in the drill press as shown in the third image and drill your holes using a 5/16 drill bit. Set the drill press so that it drills holes which are 1 3/4" deep. As you drill deeper, you will need to drill a little at a time, removing the bit from the hole frequently in order to prevent chip buildup in the hole and on the drill bit. Repeat this process for the other side piece. Then, unclamp the top piece and use a 27/64drill bit to enlarge the holes in only the top piece. This will allow the bolts to pull the pieces more tightly together.

Step 12: Tap Holes for Bolts and Test Fit Center Slide

Now use a 3/8-16 tap to thread the holes in the center slide side pieces. When tapping holes, do not attempt to brute-force the tap all the way down the hole in one go. Instead, turn the tap 1 1/2 turns forward, and 1/2 turn back, and repeat. If the tap gets hard to turn, remove it and empty the chips from the hole, then continue.

Once you finish tapping all the bolt holes, test fit the 3 pieces of the center slide.

Step 13: Cut, Drill, and Tap Holes to Mount Bearings

Now use a drill press with a 2 3/8"bi-metalhole saw to cut a hole in each center side plate for the bearings to fit into. Cut a little over half way through each plate from one side, then flip the plates over and finish the cuts from the other side, and you will end up with nicer holes. Once you have your large holes cut, drill four 3/8" holes in each plate to allow mounting of the bearings. I placed the bearing in the hole, and used a hammer and punch to mark the locations of my 4 holes with the bearing in place to be sure that the holes were in the right places. Once you have drilled all the holes, tap the 4 small holes with a 7/16-14 tap.

Step 14: Assemble Center Slide

First, use 7/16" bolts to mount the bearings to the side plates as shown in the first 3 images, then mount the side plates to the top plate. Now, use a drill press with a 13/64" drill bit to drill 2 holes 1" deep in each side of the top plate, spaced 2 1/2" apart. Use a 1/4-20 tap to thread the holes, and screw 1/4" by 1"bolts and nuts into the holes. After you screw in the 1/4" bolts, use the nuts to lock them in place.

Step 15: Add Tracks for Center Slide

Now use 4 pieces of 1" by 1/4" by 1" aluminum bar stock to make tracks for the center slide to slide in. In order to ensure the best fit possible, use the center slide as a spacer to line up your tracks (theoretically, if your cuts were perfect, the outer edges of the tracks would line up with the triangular holes in the side plates, but my cuts were not perfect, and I doubt yours are either unless you used a CNC cutter). Clamp the tracks in place, make sure the center slide can freely slide up and down the entire length of the tracks, and drill 4 equally spaced 3/8" holes in each one. Add 3/8" by 1 1/2" bolts to attach the center slide tracks.

Step 16: Cut Pieces for Top

Now cut the pieces for the top using a miter saw. If you wanted to, you could just make the big side plates taller and only have to cut one plate for the top, however, you would have to buy significantly larger plates of aluminum to do it this way, and the extra expense and waste is not worth it.

Step 17: Drill and Tap Holes and Assemble Top Piece

Now, use right angle clamps to hold together 3 of the pieces as shown in the first image, and drill two 5/16" holes through each 1/2" thick piece and into the sides of the 1" thick piece. Drill the holes 1 1/2" deep. Repeat with the other pieces on the other side. Then enlarge the holes in the 1/2" thick pieces using a 27/64" drill bit. Tap the holes in the large thick piece with a 3/8-16 tap, and assemble the top piece as shown in the last 3 images. I accidentally didn't drill the holes deep enough, and so I had to use several washers as spacers to let the bolts tighten up.

Step 18: Make Base Pieces

Now it's time to make the base pieces which will hold the side plates together and allow you to bolt your roller in place. First, cut 2 pieces of 1" aluminum plate, each 6" by 2". Drill two 5/16" holes 1" deep in both ends of each piece, and thread them with a 3/8-16tap. Then, drill two 1/2" holes through each piece as shown in the fourth and fifth images. These holes will allow you to bolt your tubing roller to a table.

Step 19: Drill Holes for Base Pieces in Side Pieces

Now drill two 27/64" holes in the lower corners of each side plate, 1" apart and 1/2" from the bottom.

Step 20: Assembly, Part 1

Now we can start assembling the pieces of the roller. To begin, bolt the base pieces onto one of the side plates. Then, flip it over and add 2 bearings, one on each side, in the location of your choice. Closer together can roll tighter radii, but requires more physical force to be applied to actually do the rolling. Add bearings on the other side plate as well. Then, if you haven't already, add the tracks for the center slide. Now bolt together the 2 side plates, and slide the center slide in between the two sets of tracks. Now cut two 9" pieces and one 18" piece of 3/4" shaft, then slide the 9" pieces in place between the side bearings and the 18" piece into the center slide.

Step 21: Assembly, Part 2

Now fit the top part in place. I recommend clamping it in place and drilling holes through both the top part and the side plates at the same time to ensure that the holes line up. Drill 27/64" holes and use 1 1/2" bolts. Next, drill 2 sets of 13/64" holes 3" apart and 1/2" deep in the top plate, then thread them with a 1/4-20 tap. Do the same to the top piece of the center slide. Add 1/4" by 1" bolts in each of the holes. Then, set the bottle jack on top of the center slide and add 4 springs, 2 on each side. Hook the springs on the 1/4" bolts. Add the handle to the bottle jack, then test it to make sure everything works. If everything is assembled properly, the center slide should retract automatically when you release the pressure in the bottle jack. When bending extremely tight radii, or using small-diameter die sets, you may need to add a piece of blocking to extend the reach of the bottle jack, as shown in the last 2 images.

Step 22: Crank Assembly

For the crank, I decided to re-use the crank wheel from the harbor freight tubing roller. If you do not have a similar crank wheel lying around, you can start off with drilling a 1/4" hole in your shaft, taking a piece of square or round tubing at least 1 1/2" in diameter, drilling a 3/4" hole in the center of the length of tubing, sliding the tubing onto the shaft, and bolting it in place through the shaft. Now that you have a temporary handle for your roller, you can roll your own crank wheel for a more elegant-looking one, or just leave it the way it is. Once you put together whatever crank you're using, slide it into the bearings in the center slide, and you'll have finished the body of the roller-bender. Now on to making die sets...

Step 23: Making the Die Sets

Before you can start bending tubing, you'll need to make a set of 3 dies for each type of tubing that you want to bend. There are dozens, if not hundreds, of different die sets that you could make, so I can't hope to cover all of them. However, to get you started, I will walk you through how to make a 1 1/2" round tubing die. I will also post more die instructions as I make more sets for myself.

Note: I am assuming that if you have access to a lathe, that you also already know the basics of how to use it. Therefore I will tell you, for example, "use a right hand turning tool" or "cut .020" at a time," but I will not tell you what a right hand turning tool is, or how to read, zero out, or use the dials to make a .020" cut. If I did, we would be here all day.

Step 24: Cut Your Stock

First, you need to cut a piece of 3" solid round aluminum bar stock that is 1 3/4" long and chuck it up in your lathe using a 4 jaw chuck. Get it as close to centered as possible, within a few thousandths of an inch is fine.

Step 25: First Facing

Now use a right-hand turning tool to carve away small amounts of the end of the die blank until it is perfectly flat and perpendicular to the sides. I carved away about .010-.020" at a time. Don't cut off more than you need to.

Step 26: Cutting the Outer End

Now zero out your dials in both directions and lock the carriage in place. Cut 1/2" in as shown in the second image, and, little by little, carve the side of the die away until it has a new diameter of 1.600". On the final cut, instead of bringing the cutter back off the blank on the Z axis before retracting it, slowly retract the X axis with the tool still touching the blank, which will smooth out any unevenness and leave a nicer finish.

Step 27: Face the Other Side

Now, loosen your chuck and flip your blank around. This time, have the chuck grab it by the smaller diameter that you just cut. Face the other side down until the thickest part of the die is 1.000" long.

Step 28: Rough Cut the Radius

Now we need to rough cut the radius. To do this, you can either eyeball it and hope for the best while using a piece of 1 1/2" diameter stock as a radius gauge, or you can calculate how deep to cut at various points along the curve. I chose to do the latter. Cut in no larger than .050 increments for each little step you make.

Step 29: Smooth Out the Radius

Now use a small radius tool to smooth out the steps in the radius. This part is really more art than science; you have to move the X and Z axes simultaneously, one with each hand, with the goal of guiding the cutter along a curved path. It takes practice, but just go slowly and don't cut too deep; you should be fine. Make several shallow passes instead of one deep one.

Step 30: File the Radius

Now finish smoothing the radius with a file. Use a piece of 1 1/2" tubing or stock as a guide for the final adjustments to the radius. At this time, also file the outer corner to a small 45 degree bevel.

Step 31: Drill Out Center

Now use a 5/8" drill bit in the tail stock of your lathe to drill out the center of your die all the way through.

Step 32: Bore Out Center Hole

Now use a boring bar to bore out your center hole little by little until it is exactly .750" in diameter.

Step 33: Finished

There's one half of one die completed, now make 5 more and you'll have a complete die set!

Step 34: Shaft Mating Options

There are 2 ways in which you can mate the drive die to the drive shaft, one of which is to cut an interior keyway and use a square key to mate with the shaft. The other way is to drill a hole through the outer side of the die, another hole through the shaft, and insert a 1/4" bolt or pin to mate with the shaft. I am using the second option because I do not have the tools to properly broach an interior keyway, and while it is possible to do it by hand on a lathe, it's more trouble than it's worth in my opinion. Note that you only have to mate the center drive die to its shaft, the other 2 can just be slid on and will do fine that way.

Step 35: Spacers

For each die set you make, you will need a set of spacers to prevent the dies from sliding back and forth on the shafts (if you make all the die sets the same width, you will only need one set of spacers). To make spacers, simply cut 3/4" shaft spacers to the correct lengths and slide them onto the shafts on either side of your dies.

Step 36: Finished!

Enjoy your new roller-bender machine!

Metal Contest 2017

Second Prize in the
Metal Contest 2017

Epilog Challenge 9

Participated in the
Epilog Challenge 9