How to Build a Bridge – Starring Diablo Wood and Metal Circular Saw Blades

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testing the bridge

What's This?This post is sponsored by The Home Depot. We have had a tremendous amount of rain over the past year, and one of the primary drainages splits our property in a spot that we have to cross frequently. Rather than walking around the drainage we decided to figure out how to build a bridge to prevent having to walk around or through the stream bed. In an attempt to keep the cost low we decided to utilize some of the steel we found on the property. Coincidentally, Home Depot just sent us the Diablo 7 ¼” Steel Demon and the Diablo 7 ¼” Wood and Metal Circular Saw Blades to test out. The Diablo blades couldn’t have arrived at a better time given the wood and metal cutting involved in this build project. Join us a we walk through how to build a bridge and as we put these Diablo blades through their paces in the process.

selecting the steel
Picking through the pile to find the right bridge pieces

How to Build a Bridge – Sourcing Materials: I Feel Like a Scrapper

We bought the property a little over a year ago from a guy that built large scale greenhouses (think as much as 100 acres under glass) all over the U.S. There was a large pile of glass, steel and aluminum in one of the pastures that had been abandoned, I assume from his early days as a builder. I found some 20’ long 6” steel C channel pieces, ¼” thickness that I selected for the runners for the foot bridge. I then found a spot 20’ wide over the stream bed. This engineering based on convenience would be a recurring theme throughout the project. We suggest you actually consult with an engineer and local codes before you embark on your own bridge building adventure. You’ll want to make sure whatever you’re using is more than sufficient for carrying the foot, bike or ATV traffic you plan to send across it.

I also had a pile of thin wall 2” steel tubing I had scavenged from the overseas containers that brought wine and concentrates into the winery where I had worked. They would provide the support struts for the decking. I had an entire hardware store worth of fasteners in the shop courtesy of the previous owners. Fortune was smiling on me as I found a bin full of 2” self tapping hex headed fasteners perfect for securing the decking. The one component I would need to purchase would be the decking. I decided on 5/4” pressure treated wood decking for cost effectiveness and ease of use.

loading the arch
I used a home made log arch to move the steel
moving it to the shop
It was easy to pull the runners to the shop with the ATV

How to Build a Bridge – Assembling the Beast

My brother and his wife were visiting from Colorado; I immediately pressed them into service as we dug out two pieces of the C channel from the weeds and hauled them up to the shop. At 20’ long each piece was approximately 185 pounds. I needed the help. We got them up on sawhorses, spaced them at 32” and squared them to each other. Next step was to cut the steel tubing and attach it to the runners. This was the moment I was dreading and I struggled to make the leap of faith. I loaded the steel demon into my oldest and least expensive saw and gave it a go.

The Diablo Steel Demon
The Diablo Steel Demon is a cut above any saw blade I have ever used.

I was stunned; the blade cut through the tubing like it was butter. I thought at that point these folks were onto something. Since I needed 10 more cross struts I clamped 3 pieces of tubing together, same result, the blade cut through smoothly and squarely leaving no burrs. I have been cutting steel with a chop saw with an abrasive disc forever, its noisy, messy and slow, how could I not have known about these blades. I was further impressed that the last cut on the struts was as easy as the first. I then cleaned all the surfaces to be welded with an abrasive polisher on the angle grinder and welded the struts into place at 24” on center. If you’re exploring how to build a bridge, and your bridge involves metal and wood, these Diablo blades are definitely worth having on hand.

first cut
I tentatively made the first cut with the steel demon and was pleasantly surprised.
A clean cut
The cut was square and clean
cutting multiple struts
I clamped 3 pieces of tubing together to speed the process.
finish cut
The blade cut quickly and smoothly through the multiple pieces of tubing.
cleaning for the weld
I cleaned all surfaces to be welded with and abrasive pad on the angle grinder.
welding the cross supports
Welding the cross pieces to the runners
how to build a bridge - framing complete
Support struts attached at 24″ on center
laying out the decking
Laying out the decking alternating the 16′ pieces with 4′ pieces

I then fastened the decking onto the struts using the 2” self tapping metal screws alternating 16’ pieces with 4 footers. The bridge deck was complete!

fastening the deck
Fastening the deck boards with 2″ self tapping hex screws.

The Finishing Touches

When I originally conceived this how to build a bridge project, I thought I would fasten the ends of the bridge to 4×4 posts buried in the ground to help level and secure the bridge in place. There were already flanges welded onto each runner at one end, but I needed to cut the bottom of the C flange off the other end to allow the fitment of the 4×4. The blade I have was rated for ¼” plate, and the channel is ¼” thick, but is closer to 3/8” at the flanges. I marked the cuts, fired up the old saw with the Diablo steel demon and buzzed right trough, again like butter. The result was a smooth, almost polished cut. The 4×4 posts would fit perfectly.

cutting thick steel
I had to remove part of the lower flange to fit a 4×4 support.
sparks flying
Finishing the cut, sending sparks but cutting smoothly.
I'm impressed
I’m impressed, it cut through 3/8″ of steel like a demon.
A perfect fit
The 4×4 support is a perfect fit.

Moving the Foot Bridge

All that was left in completing this how to build a bridge build was to move the bridge into place. That was no easy feat considering it had to be up to about 500 pounds by now. I felt the best way was to drag it into place with either the big ATV or the tractor, and the best way to move it was on skids. Sticking with the low cost reusing old materials scheme, I settled on digging some old scrap 4×4’s out of the wood pile (farmers never throw anything away) and cutting them at an angle to make runners. The only problem was there were lag bolts, screws and nails embedded in the old 4×4’s. No problem, I swapped out the steel demon for the Diablo wood and metal blade and started cutting. I sawed through deck screws and a lag bolt at one point, I saw the sparks, but that was the only indication that I was hitting metal. Again, the last cut was as smooth and effortless as the first. I then lagged the runners onto the bottom of the bridge runners and pulled it quite easily into place with the ATV.

scraps for the skids with embedded metal
All the scrap 4×4’s I had at hand were full of embedded metal
cutting the skids
I cut the skids using the Diablo wood and metal blade.
clean cut
It sliced through deck screws with no problem.
another clean one
It also cut through a lag bolt, with sparks flying being the only indication I was hitting metal.
on skids ready to move
On the skids and ready to move.

I attached a cable and dragged the bridge into place with the ATV.

moving out
The 500 lb foot bridge moved easily on the skids.
in place
The bridge in place over the drainage.

Once the bridge was in place I abandoned the use of the 4×4 posts to hold it in place. It settled perfectly in place and was not about to go anywhere. In the event it settles unevenly I will revisit that option.

testing the bridge
My assistant tests the safety of the bridge, which is now open to foot and bike traffic.

My Epiphany – A Whole New Way of Looking at Steel Cutting

I have to admit that I don’t always keep up with what’s going on in the world. Technology, social media, entertainment, keeping current seems to require a little more energy than I’m willing to put forth. In fact I was shocked recently to learn that the Beatles had broken up. So my skepticism around the Diablo blades was understandable. My experience with the usual pricey carbide circular saw blades was always that as soon as you nicked a screw or nail your shiny new blade was relegated to junk blade status.

Diablo blades
The Diablo 71/4′ Steel Demon and the Diablo Wood and steel circular saw blade

Up until I tried these blades I was completely unaware of the advances in saw blade technology. Diablo offers a wide variety of blades for all manner of applications in a wide variety of sizes. For me this opens a door to many possibilities in metalworking, which I fully intend to explore.

The Diablo Steel Demon 71/4″ saw blade and the Diablo Wood and metal 71/4″ saw blade are available at Home Depot for $29.97 and $21.97 respectively.

Buy Now - via Home Depot

Buy Now - via Home Depot

I acknowledge that The Home Depot is partnering with Home Fixated in sponsored content. As a part of the sponsorship, Home Fixated is receiving compensation for the purpose of promoting The Home Depot. All expressed opinions and experiences are our own words. This post complies with the Word Of Mouth Marketing Association (WOMMA) Ethics Code and applicable Federal Trade Commission guidelines.

Photo of author

About Stephen

Stephen hails from a family of DIY’ers, the delusion that no job is too big or complex to tackle on your own originally instilled by his father and further reinforced by his brothers, who are equally afflicted. His first real project was the complete restoration of an old farmhouse in Upstate NY, which was followed by another, setting the pattern. After 40 years in the wine and spirits business (sounds far more glamorous than the reality) he recently retired to an 80 acre sheep farm, where he will continue to farm until his retirement savings are exhausted. As a co-owner of 30 something bicycles (a devotee of the N+ 1 theory of bicycle requirements, where N= the current number owned), he is typically found tinkering on his latest build or out testing said results. Stephen spends his spare time (face it, all of his time) drinking good coffee, currying homegrown produce or fixing whatever is currently non-operational. He also spends whatever time he can with an ever growing extended family. When his wife retired they planned to do as much cycle touring as their legs will allow, but the sheep are pretty demanding.

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2 thoughts on “How to Build a Bridge – Starring Diablo Wood and Metal Circular Saw Blades”

  1. You know, it’s funny, that I have used wood/metal carbide saws-all blades to cut through steel i-beams, but Never would have thought to try a circular saw blade on one! And I’ve been in the building trades for over 40 years! This is exciting. Of course, all new tools & products are to those who use them.

    When the oscillating saws first came out, I thought they were junk, untill I got one for Christmas. You might have thought someone had given me another pack of socks? But, after using it for all kinds of projects, instead of the old trusty saws-all, it’s become one of my go to tools. Cutting the tops off of toilet bowl anchors is just one of many great uses. Doing drywall, cutting holes for outlets. Any kind of flooring projects, a must use tool.

    • David – I am frequently surprised by the advances in hand tools. I was skeptical to the point of thinking I was about to trash my circular saw. After using this blade I am getting rid of my metal cutting chopsaw and replacing it with a 10″ metal demon in my ancient delta mitre saw.


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