It came time to put a couple of uncompleted projects off to the side. I have shoved both the gazebo table and the lathe stand into the corner. Trust me, I did it for good reason and not as a result of laziness. It was time, once again, to add to my inventory of garage tooling. The story goes like this…actually before I explain my story I have to first place some blame. It’s the plasma cutters fault. There I said it. The Hypertherm is responsible for my shop tooling issues over the past little while. The reason is that the machine performs so well and it allows my to cut so many different sizes and shapes of metal that it increases the level of fabrication. I have been angry at the machine for over a year now because it has made my Millermatic 135 MIG welder the most under powered piece of shop equipment I have however that is a story for another time.
The original story goes like this. The plasma has allowed me to start using sheet metal for projects. I am not a fabricator that works well with sheet metal. I visit the metalmeet.com forum to drool over the talent, technique, and tooling there is when it comes to sheet metal work. That stuff is a true art form. The shrinking, stretching, and manipulating of the metal is amazing. I have a great deal of respect for the people how have taken the time to try, learn, and perfect the talent. Anyway…back to me and sheet metal. Both the lathe stand and the gazebo table need some sheet metal added to them and for both projects I need a way to bend it. So as you have probably figured out it was time to add a sheet metal bending brake to the garage family (I do not suspect anyone will get offended with him)
The dilemma is this, I work by the rule “when in doubt build it stout”. Most of my projects weight is not a factor. We all have fear in our lives, something that scares us. For me it is light gauge sheet metal. It is flimsy, it warps, it is a pain to weld, and I have no idea how to manipulate it the way I want. This leaves me dealing with the thicker stuff. How about 10 gauge? Yeah!!!!! Now we’re talking, that’s man steel. Except it turns out I am not man enough to bend it. To buy a metal brake is not an option; it is not in the budget. Like with most equipment you get what you pay for, cheap brakes don’t cut it (I mean bend it). Even the budget ones that are rated for 22 gauge aren’t great. To get a brake that can do 10 gauge I would have to budget $5000? Maybe $6000 or $7000? I am buying a Millermatic 252 before I drop that kind of dough on a bender.
So it comes down to having to build one. There are only about 232000 people that have posted their version of a homemade bender on the internet. I spent a very small amount of time snooping around to see what others have done. There was not a lot I found that was of interest to me. Come on…I want 10 gauge. I decided to trailblaze the project.
So here it is the build criteria. Cheap! I believe that if something is worth building it is worth building well, budget is usually not an issue for my projects. With the brake I am not sure how well my idea will work so I am not going to sink money into the project. 2nd criteria, it has to be able to do 10 gauge (I think I have already mentioned that). 3rd it has to bend lengths up to 48”. 4th it would be great to be able to incorporate a box pan style. And finally 5th it has to easily be stored and not take up useful shop space. Shouldn’t be too difficult.
Before I continue I need to confess something. I am going to cheat. There is a reason bending brakes cost $5000 and so if I am to think I can build an equivalent in my garage for under $100 I think may be demented. The trick to making my budget build work is to thin up the steel. So although I am going to use 10 gauge it is going to get cut partway through which will actually cut its thickness in about half.
The concept is this. The sheet metal is going to get clamped down on top of the brake. Then, using my Dewalt DW362 (discontinued) circular saw, I am going to make a cut halfway through the steel at the point of the desired bend. Once the cut is made the steel will get slid over and clamped down again in the bending portion of the brake and the bend will be made.
In order to have some idea as to whether or not my idea would work it required a little bit of R&D. I mounted a metal cutting 7 ¼ inch 24 tooth carbide tipped saw blade in the saw. The blade is rated at 6000 rpm and the saw spins out at 5800 rpm, should be good to go. I set the depth of the blade to about half of the metal thickness and buzzed it through a piece of metal. The metal was then clamped to the bench and, using Vise grips, I made the bend. First problem, the width of the kerf did not allow me to make a 90 degree bend. I think I may have maxed out at 70 degrees. So I tried again. This time I made a second cut set just slightly off center to the first cut to give me a simulated wider kerf. Now I was able to bend to a perfect 90 degrees. I thought about doubling up the saw blades but 2 blades are a bit too thick. The bend worked out well and resulted in very little bowing. The steel wants to bend at the weakest spot so when I performed the bend it wasn’t being forced it was more like being folded. The strength of the bend, once bent, was good. It held its position very well and was not at all weak or flimsy along the bend seam. The second problem was trying to keep the depth of cut even througout the entire length. When I feed the saw into the metal and when I exit I have a tendency of tilting the saw. This results in me cutting completely through the sheet metal at both ends.
So the idea is this. Build a brake that allows me to “scribe” the bend line using a circular saw and then perform the bend. The brake will be designed to allow only 1 side of the bend to visibly look good. On the opposite side of the bend, where the cut line is visible, a few tack welds can be placed to help add strength if needed.
I made a trip down to the metal yard and dug through their cut-off rack. I was able to pick up a 5 foot section of 3” channel, a 5 footer of 5” channel, and a 10’ length of 2 x 2 x 3/8 angle iron. Total cost? $68! Add to that the budget $20 circular saw blade I previously purchased and that puts the build cost at $88. The rest of materials will be coming from stuff lying around the shop.
Starting in no particular order I began with building the hinges that will allow the 2 x 2 angle iron to perform the bending. I used a left over section of 1.250” seamless pipe with a .250” wall thickness from the BBQ spit build. I decided to make the hinges greaseable as well as implement a set screw for securing the hinge pin. The overall length of the hinge is 5 inches. The seamless pipe was cut into sections using the band saw. The end and center sections were then drilled and tapped to accept a grease fitting and a set screw. The hinge pin was machined from an old broken section of a slide hammer. The shaft was trimmed down to .725” to allow for a smooth fit into the hinge body. It was pure guess work as to the size the hinge had to be. I’ll have to wait to see if I guessed right, hopefully the strength will be adequate.
The section of 5” channel is going to act as the base for the entire brake. A 5 foot section of 2 x 2 angle iron will be hinged to the channel and perform the bending. The trick was to hinge the angle iron to the channel to allow for the pivot line to bend even with the edge of the channel and angle iron. Both the angle iron and channel got notched at the ends approximately 5/8” (1.250” halved). With the metal notched and the hinge machined it was time to weld the assembly together. The challenge was going to be ensuring that both hinges are welded along the same plain so that no hinge binding will occur during the bend. I set the hinges into the notched sections, spaced them using 1/16” welding rod and then placed a scrap section of 1” angle iron overtop connecting the 2 hinges together. Tack welded the hinges in place and tested the pivot function for smooth operation. 100%! No binding. Good to go, the hinges get TIG welded into their permanent positions.
With stage one complete it was time to move on. Again, in no particular order, I directed my attention to the 3” section of channel. The 3” channel is going to be the top side of the clamp which sits on top of the 5” channel that is going to secure the sheet metal for cutting. It will also act as part of the guide for the circular saw. The channel needed a slot run down the center ¼” wide and 52” long to allow for the carbide saw blade clearance. I could plasma it, I could cut it with the angle grinder but I figured it was time to break in the milling machine. I clamped the channel down on the table, squared it up, and with a ¼” 4 flute HSS end mill I carved a slot down the channel. Due to the length of the steel the milling machines working envelope was a limiting factor. I ended up having to reset the channel 3 times in the machine in order to achieve the 52” slot. I measured the accuracy of the slot from the start of the cut to the end. It turns out I was only off .015”, not bad for a first try. The .015” will have absolutely no affect on the function of the brake.
I feel an explanation may be required at this point. As I mentioned earlier I need more than a saw blade kerf in order to bend 90 degrees. The saw blade has a carbide tooth thickness of .080”. Until I do some more R&D I will not know exactly what width kerf I will need however I am fairly certain double the blade thickness to a .160” will be too much. The slotted 3” channel is going to act as the guide for the saw. Right now the guide slot runs exactly down the center of the channel. The idea, if all goes as planned, is to off set the saw approximately .030” in the guide. I will start by making one saw cut one direction down the guide and then flip the saw and run it done the guide the opposite direction. This should give me a .100” kerf. If I need more or less kerf all I need to do is adjust the saw on the guide. If this is confusing I apologize, it would be easier if I could just scan my brain and post the image.
As the bender sits now the hinges are built and welded. The 2 x 2 angle iron now pivots freely on the 5″ channel. The next stage will involve having to mill a sharp edge on the upper 2 x 2 angle iron that will be performing the clamping. The factory round edge on the angle iron is not sufficient for giving the metal a clean, crisp bend. Milling one side will give the bending edge a sharp clean edge. It’ll give me a chance to get more familiar with the milling machine. I need the practice.