It’s not very difficult to build a street rod frame — if you know what you’re doing. Don’t worry. We’re here to help with a nicely detailed explanation, in two parts, of how Bob Hamilton builds a street rod frame. It can be done in your home garage and the only special tool you’ll need is a welder. If you don’t have one, you can even get a friend to provide his and maybe he’ll even do the welding.
Often, a street rod frame is just two straight lengths of rectangular tubing joined by crossmembers. But to make things more interesting and pleasing to the eye Bob Hamilton likes to build a street rod frame that is tapered to follow the bottom contours of the body he’s using. That is particularly important if you’re building a highboy street rod or if you decide not to channel the body the full depth of the frame rails in order to have more cockpit room. Or you may like the look of the frame rails tapering from the firewall to the front crossmember, which is a more pleasing look than a big wide front crossmember.
All of this street rod frame construction is covered in incredible detail in the StreetRod 101 Hot Rod Frame and Chassis Construction DVD. The 4-1/2 hour instructional DVD covers every aspect of street rod and hot rod frame and chassis construction. And the nice thing is the techniques illustrated can be used in the construction of virtually any hot rod or street rod chassis, whether it be for a 1927 Model T, a Model A, a ’23 T-Bucket or even a ’32 Ford.
For this installment, we’ll let Bob Hamilton explain how he builds a tapered street rod frame in his own words.
Here is the plywood table with the body outline and the frame outline. I set this up prior to building all of my frames – now. Years ago, I just measured and laid things out on the floor and took my chances. Now with everything up on the table, I can see and build with a lot more accuracy. This frame will be built using 1 ½ x 4 x .188 wall rectangular tubing. Most of the frames I build are 1 ½ x 3 x .188 wall rectangular tubing with the rounded edges. This frame will be constructed in three parts: the middle or side rails, the rear section which contains the kickup, and the front section which I will taper from in front of the front wishbone brackets to the bottom of the round schedule 80 tube front cross member which will make it 3 inches. So the taper will be from 4 inches to 3 inches which will give the frame some accent in the front and it will not look or be so boxy.
Two things to notice with this picture: One – I cut the angle for the kick in the rear ( 22 ½ degrees) before I started the bends in the frame ( it’s just easier when the tubing is straight and flat). The second thing to notice is that there are two ¼ -20 holes with studs on each end and are in the same location on each rail in the center @ ¾ of an inch. This is so that I can use them for reference points as I build and curve the frame. The location is not important – what is important is that they are in the same place on each rail. These will stay and be used until all the brackets and measurements are in place and are right. Then when I begin to finish weld and finish the frame, these will be welded up and will no longer be used. There needs to be points of reference otherwise the end product can be off enough that it could affect the performance or outcome of the product.
After deciding where the first bend will be, the cut is made and a disc and small 4 inch hard grinder are used to bevel the cut edges and open the cut if needed. The come along is then used to pull the frame together (remember – I’m only cutting through three sides). When the correct angle is obtained, tack the bend in place.
The cut is made on the second rail ( in this case remember to turn it upside down because it is an opposite rail and also has the angle cut on the back). Continue the same procedure with the beveling etc. and then use C – clamps and angle iron / flat bar with both pieces so that they will be the same – and tack them it in place also.
Here is an inside shot with the rail to be tacked on the bottom and the clamps etc. in place. This is the critical time and it may have to be undone and the cut opened up some more in order to make both sides match.
The next cut is on the outside because the frame is going to bend the opposite direction. Here I have to be careful that the tacks are strong enough to allow the rail to be pulled in the opposite direction. I weld the top and bottom and then put a short 1 inch tack/weld on the cut to ensure that the cut will not break loose and cause more problems. If this happens, I’ll need go back and clean off the old tacks and re attach the come a long and then re – tack before I can pull the rail the opposite direction.
Again I use the clamps, come a long, and metal to line up the rails. Notice how the cut ends are opposite. If I forget to do this, I will have two of the same side rail and it just won’t work. Sorry.
We’ll continue Bob’s street rod chassis build how-to in tomorrow’s Part 2 installment. But you might want to go ahead and order Bob’s incredible street rod chassis building DVD so you’ll have ALL the information on how it’s done.
You can just sit back and follow along as you learn from Bob’s years of hot rod building experience. Here are some of the things you’ll learn about hot rod chassis building in this 4 1/2 hour video:
- How to set up an easy, economic chassis-building table
- How to lay out your chassis dimensions, depending on your body and your engine
- The importance of establishing a “reference point” on your frame rails and putting in temporary studs for one-man measuring
- Importance of rail-to-rail cuts (so you don’t get confused)
- Using angle iron to align frame rails for uniform work
- How to curve your frame rails to the contour of your body using an inexpensive cut-off/grinder and simple puller to make it an easy one-man job
- How to make all your frame contouring cuts the same depth
- How to make angle cuts in rounded edge tubing so that the blade won’t walk off the edge
- How to properly bevel cuts for best weld penetration and strength
- How to correct mistakes in your cutting or welding (hey, it’s part of hot rodding — Bob shows you how to fix it, suck it up and move along)
- The many important uses of angle iron, flat bar and c-clamps in your chassis construction — to save you time and trouble
- How to adapt what Bob illustrates to your own style of hot rod build
- How to properly square the frame
- How to chamfer tubing for welding angled joints and make sure they’re square
- The trick of building frame rails in pairs to ensure proper fit
- How to avoid the dreaded “multiple error concept” that can throw your entire frame out of alignment
- The secret to avoiding days of weld cleaning/grinding when you finish your chassis
Click here to order your own copy today!