Frame cutting

[shannondeese]

What is the best way to cut the frame when bobbing the Deuce. Since it is tempered I am a little worried about using the torch. Thanks.

 

[ralbelt]

I would think a gas cut off / demo saw with an abrasive blade for steel would give a nice clean cut you could rent one .

 

[OptimusPrime]

I relocated and mounted my rear axle first, then drove it to a local welding shop and had them plasma cut it to length and blow the larger holes out for the taillight wiring grommets.

 

[Hammer]

Plasma torch works great. It puts barely any real heat into the metal surrounding the cut.

Besides, this will be the END of the frame, not something in the middle. Changing the temper on that metal really isn't going to be that big of a deal.
Plenty of people have used torches for this, and I haven't heard any problems about it yet.

 

[Jones]

Are you cutting off the excess or sectioning it? Frames are toughened but not necessarily hardened. Designers wanted the frame to still be flexible for negotiating rough terrain.

If you're just removing the tail ends there shouldn't be much trouble with too much heat since nothing much mounts that far back except maybe the rear bumperettes or taillight brackets.
The pintle hitch's crossmember has enough gussets and bolts holding it in that you'd have to heat the frame's last foot or two nearly red-hot to do any harm there.

If you're sectioning it then heat is a real concern-- not just while cutting but when rejoining the frame sections. Too much heat will leave soft spots without the ability to rebound.
The boundry edge between soft and unsoft is often the place where stress risers will form, leading to cracking.


I've had good luck with a Sawzall with a good course-toothed, metal-cutting blade. Running at less than full on will make the blade last longer. Keep enough force on it to get a good cut but not so much that the blade heats up.
Another handy tool is a 4" angle grinder with a .040" cut-off blade. While you can even cut through a frame rail with one if you're patient, they're handiest for trimming and clean up. i.e. "Breaking" sharp corners or taking heads off rivets or rusted or stripped bolts.

 

[russ81]

Personally my favorite tool in the fabrication department is a Port-a-Band. It cuts very, very quickly, very cleanly, with no heat build up, and makes a very nice smooth edge. It's not near as noisy as a grinder with a cut off wheel, no sparks, and no vibration like you get with a saber saw. My guys use them every day at work, and I have one for my personal use at home. It is truely one of the best, most effiecient tools I have.

P.S. Milliwaukee makes the best one on the market!

 

[Ridgerunner]

I used a 4 1/2" angle grinder, with a 6" .060 cut-off wheel. It gives you a nice clean cut.

 

[comdiver]

I went low tech. SawZall, one blade, total cut time 14 minutes and one or two minutes to clean up with a grinder. Hole saw for the wire and air line holes (I did use a mag drill for this). Don't forget to support the frame while cutting and measure twice, cut once.

 

[GoHot229]

I'd just add to 'JONES' directions that it would be best also to use a large enough torch to cut through it quickly, in that a too small of a torch will take a bit more heating before you put the oxygen to it and it is cutting away at a good clip.My thinking is that a too small a torch will heat more area by convection than the bigger torch which reaches cutting temp much quicker.

 

[DEVO]

Vote #2 for the portable bandsaw. Clean, quiet, precise. Definitely second or third on my list of favorite tools!!

 

[Rattlewagon]

I own torches, a bunch of grinders, a plasma cutter, a few sawzall's, I even have a hacksaw somwhere but when I get to anything like this, I will grab the portaband more often that not.

#3 for the portaband

 

[KsM715]

Ok so cutting off the end of a bobbed truck is not much to get concerned about, but what if a guy (me) wanted to section and lengthen the frame. What would be the best way to join the two pieces back together? I thought it could be welded back together with the new section inbetween but after reading this Im not so sure about that.

 

[m16ty]

I don't think I've ever seen a portable bandsaw with a big enough throat to cut a deuce frame. Could be one but I've never seen it .

Jeff, We've added frame in the middle on several civilain trucks at our shop. We have always cut with a torch or plasma, welded the extra frame in, and then double frame it across the joints (bolted in). I know there are people that will say that you've heated the frame too much and it will fail but this method is standard practice in any big truck fab shop I've ever been in without a failure in the splice when it's put back together by somebody that's a competent welder.

 

[dburt]

There is a 7-inch metal cutting blade made for a skill saw, they are amazing and cut thru steel like wood. I have cut up to 5/8 inch plate with one, and was so suprised to see the clean cut it made. But it is hard to beat a portable bandsaw, or a plazma cutter. If you cut and section a frame, do it on at least a 45 degree angle, weld up your cut and then plate the back side and the other side with at least 1/2 inch plate extending past the end of the weld at least 18 inches at each end. Use at least 4 5/8 inch grade 8 bolts that are thru-bolted on each end and you should be good to go. I have seen large commercial trucks that had a section of slightly smaller frame about 36 inches long installed inside of the sectioned frame where it was welded back together, and was thru-bolted, not welded, for the double frame strength.

 

[Jones]

KsM715, Of course, the best way would be to find a frame long enough to use as is.
Second choice would be to get a scrap frame and cut both the project truck and the scrap so that the two sections together give you the desired length with only one joint to worry about.

Two fish plates and two channels to bridge the joint by about 1 1/2 to 2 feet beyond the seam in both directions. On each frame rail the channel fits over or into the frame channel (your choice) with a fish plate on the opposite side. These should be hot riveted or bolted back together.
I know guys weld on frames and say they have no problems but I don't trust a welded frame rail-- seen too many welds fail or cracking in the area of the heat boundary.
Another thing I'll cross the street to avoid is welded steering components.

 

[tm america]

plasma cutter is what i would use just fast clean cut.but my second choice would be a sawzall since most guys have one or they are fairly cheap to get or rent

 

[tm america]

i see alot of hack big truck shops weld peices of frame on to add length and ive seen alot of em bend or crack .the frames on heavy trucks are tempered to allow them to flex without cracking i wouldnt even think of welding a frame on a truck that has a tempered frame that is going to be used offroad or haul-tow heavy loads .just think how bad it would suck to go through all the work to bob your truck only to short cut something as important as a frame then find out it has cracked and keeps cracking ,then have to go through way more work to change the frame rails .if its worth doing its worth doing rightya people have done it and got lucky and alot of people found out the hard way why its not a good idea.question is do you feel lucky or smart

 

[russ81]

I don't think I've ever seen a portable bandsaw with a big enough throat to cut a deuce frame. Could be one but I've never seen it .


Hummmm......I cut mine with one. A regular one. Not some special made deep throat monster. Just a normal, every day, standard ole` port-a-band.

 

[shannondeese]

Thanks for the advice. I think I'll go buy a porta band. I really aprete all the comments.

 

[shannondeese]

Tha t should be apreciate. Can't type today.