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Best way to cut 0.050" 4130

digidocs

Well Known Member
What are your preferred methods for cutting brackets out of 4130 0.050" plate?

I have a "high-speed" bandsaw that I use for aluminum, a jigsaw, angle grinder, and standard hand tools. I'd love to use the bandsaw, but I think it may run a little to fast for steel. Perhaps the jigsaw or angle grinder might be a better choice?

Thanks for the help,
David
 
For long cuts I use a Bosch jig saw with metal cutting blade, but mostly a hack saw and a bench vise.
 
The rule of thumb for any metal and a toothed blade is you want at least three teeth in the metal. Obviously, that would require a very fine blade with .05 sheet. Also, whacking blade teeth into the metal from a ninety degree angle guarantees a rough cut. I have yet to see a reciprocating blade (jig saw) cut metal well.

If you have a sheet metal shop, roofer or spouting outfit near by they can cut you long strips to various widths. Below is a link to a cheap cut off "chop" saw with an abrasive cut off wheel from Northern Tool. This will give you a nice straight cut ready to deburr. Better still is a table saw with an abrasive wheel. With that you can cut from large sheets with great results. I assume I don't have to go into the safety glasses and gloves speech on this forum but will until I learn the customs :)

http://www.northerntool.com/images/product/2000x2000/224/22453_2000x2000.jpg
 
Fiber cut-off wheel in an angle grinder, preferably pneumatic.

ebbdb35d-a355-4a1e-ba94-7959fcdb642f_1000.jpg
 
How long of a cut? The die grinder would work fine on short cuts. Cut close to your desired dimension, then fine tune with a vixen file.
 
Me 2

This sounds like the rudder cable links F-10104 step 1 (38-10)? I've got the same question.

I'll go a bit further - how did you create the R1/4 for the outside? I can grind it down to be close, but that seems crude. Since its connecting a flight control, things start floating around in my mind like overheating material or removing too much material (especially if my hole wasn't perfectly centered :eek:).

Is there a nicer way? Something more elegant?

Sorry if this is thread drift.
 
Band saw.

I cut a peace today with a 32 tooth per inch band. Just cut it on the outside of the line and file it smooth. Just what we do. Yours, R.E.A. III #80888
 
This sounds like the rudder cable links F-10104 step 1 (38-10)? I've got the same question...

If it's just cutting a narrow strip to length, use a cold chisel with a vise. If the chisel is reasonably sharp and you hold it at the right angle, it will make a clean cut. The part cut off will have a bit of a curl to it, but the vise will flatten that out nicely. After cut to length, you can angle the strip in the vise and cut off the corners too. Less work with a file that way.

fig035.jpg
 
things start floating around in my mind like overheating material or removing too much material (especially if my hole wasn't perfectly centered :eek:).

Most of the 4130 on an airplane is welded. Pretty sure you won't see more than 2000* with a cutoff tool :). Reasonable heat is not an issue for most non-treated steel. I use abrasive wheels; Mostly a cutoff tool and occassionally a chop saw.

Larry
 
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A bandsaw is fine for .050 4130 sheet, given enough teeth and low blade speed. The chop saw is reserved for heavy tube and angle sections, or as Larry said, an edge that will be subsequently welded. Mostly I just use a hacksaw.

If you must use abrasive cutting tools (or a laser), remember it doesn't matter how hot you make the part. Given the section thickness we use in light airplane construction, what really matters is how rapidly you cool the part. 4130 is an "air-hardening" steel. Cool it rapidly and it becomes very hard and rather brittle. How hard mostly depends on the cooling rate. Conduct an experiment; warm a piece of 4130 scrap to dull red, then cool it rapidly (dunk it in a water bucket, squirt it with an air hose, or just wave it around in the air). Now try to drill it, or file it.

When cutting a 4130 part with a abrasive tool, the cut edge is heated near red, then quenched by the mass of adjacent cool metal. As a result, the edge is hard and brittle, while the balance of the material remains ductile. We want most of our airplane parts to be ductile, meaning they bend, stretch, and otherwise deform long before they actually break. The problem here is that a quenched edge is not ductile, and the edge is where cracks start. Think of it as a strong but brittle crust on a softer center.

So, good home shop practice says to use toothed cutting tools on 4130. Can't get hot, so it can't be quenched, so it remains ductile, and as a big bonus, easy to edge finish with hand tools.

If you must use a cutting method that heats the material, your goal is slow the cooling process. One way is to heat the whole part so it can't quench itself. Given something like a laser cut part, simply remove the quenched edge with the belt sander (you were going to edge finish anyway, right?). Do it while holding the part in your hand (rather than with a gripping tool), a sure way to make sure the part doesn't ever get very hot.

The same quench rules apply to welding. Cool slowly. It also applies to drilling. A novice will spin the drill fast, as he would (correctly) for aluminum. It will work on 4130 if the bit is fresh and sharp, but if it's dull, or not enough pressure is applied, friction makes the material under the tip of the bit get hot. Since the drill isn't cutting well, our novice stops drilling for a short break, or to change bits, and the hot material is immediately quenched. When he resumes, the new bit won't cut, because the bottom of the hole is hardened. It's all very amusing to the experienced, unless of course the novice happens to be using your drill bits ;)
 
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I'm building some push-pull control cable brackets.

OK, not sure what shape they are, but assume you they are one piece. Because of the difficulty of making 4130 parts I usually make a cardboard template, then an aluminum piece to get the bending correct, then make the steel piece. At least for the first part. The aluminum piece becomes the prototype. I use a Bosch 1587AVS jig saw, variable speed. I have a box full of others that would not cut metal. The blade has a roller down near the material to provide back stiffness and the blade orbits slightly. It has to be held firmly or else. I suppose a band saw would work too, but curves don't come easy, regardless, so I use carbide burrs for finishing to the scribe lines and/or sand/file for finishing. Either dremel or air-powered die grinder. Round files are good, just take a little longer. What ever works for the radius at the time. Even good sand paper on a dowel. Take care with the 1/2" dia burrs, they spit out some nasty shards, get caught in eyebrows etc. 4130 so they are sharp and strong. I use a face shield, cover my head to keep out of hair, long sleeves, tighten my collar and use a vacuum if possible. Depending on the amount of material being removed. Don't brush off skin with your hand. The vise (al jaws make a nice bend), or HF bending brake works ok for bending leaving a gap for a proper radius.

Drill with lubrication for cutting and cooling. A good step drill but should work, but don't remember using one. Again, secure the work.

Good luck with your part. They are usually more difficult in the mind than hand.
 
If you have the budget, or can find a good used belt sander, like this:

http://www.baldor.com/brands/baldor-reliance/products/motors/grinders--buffers--lathes/belt-sanders

These are a must for shaping steel. You need a minimum 48" belt, 72" is better. The long belts reduce the heating of the part. Shorter belts recirculate the hot spent material as do normal grinding wheels and disk sanders.

Of course , your don't "need" one of these for an RV project, but they spoil you quick anytime you want to shape aluminum or steel.
 
Very little info found searching for the F-10104 Rudder Cable Links brought me here. I decided against getting 4130 .050 steel plate and most likely butchering it into links. You asked the best way to cut 4130 - a waterjet. I made a few CAD step files which you can use to order this from your favorite online service. https://www.thingiverse.com/thing:5628281 I got mine made for less than a hundred bucks. Considering the material, shipping and time to ultimately fabricate a sub-standard part this just seemed reasonable to me. I hope someone finds this helpful and saves just a little time and effort.
 

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For all kinds of brackets and things, like bell cranks, control horns, mounting brackets, I make a drawing and take the material down to our local water-jet cutting place. For very little money, they cut out all the parts you want, pretty accurate, neat and tidy. Holes located and everything. I usually dimension the holes about 0.020" undersize on the water jet, so can do the final drilling to correct diameter.

A batch of brackets that would take me two hours to cut out with a hack saw or band saw, and have to grind/sand the edges to shape, locate and drill holes, etc, instead costs about $35.

The price scales with the thickness of material, and the length of the cuts. I've had them cut me bell crank mount brackets from 1" aluminum, down to steel parts that are 0.050" thick, and just about anything in between.
 
Use caution cutting steel on the same machine you have already cut alum on.

This is especially true for cutting tools that generate sparks.
 
Inexpensive metal cutting bandsaw

Swag makes a small metal adapter table that converts a hand held band saw which is available for a little over a hundred bucks into a small metal cutting band saw. Perfect for making small parts

Regarding bench grinders, never grind aluminum and steel or iron on the same wheel. That mixture makes a powerful explosive used to weld railroad tracks called thermite
 
online

I recommend sendcutsend.com. We had them cut stainless door hinge covers for our -10 from stainless. Quick, inexpensive, and they have a simple online design tool if you do not have a CAD file...
 
cutting

For straight edges most any jump shear will cut .050. A high dollar shear such as Pexto will cut .063.
Built from scratch EAB the only thing I routinely "farm out" is aluminum welding
 
Man I know this is an old thread but I'm struggling with making these rudder pedal linkages.

Thank you for the Thingiverse link, I'm going to take that and the Van's drawings up to a local fabricator tomorrow to see if he can make it happen.

I tried using the local FBO's Jump Shear and it barely made an indentation in the metal.
 
Doesn't Van's supply a strip of steel for the linkages? All you have to do is cut to length, round the edges, and drill 'em. A hacksaw, a file, and a drill should be the only tools required.

Now, if you're hacking them out of a sheet, that's another issue.
 
What Kyle said.
Or just go to HD or Lowe’s and buy a strip of metal the correct width and cut off the correct lengths.I have done this and it works great.
 
Man I know this is an old thread but I'm struggling with making these rudder pedal linkages.


I tried using the local FBO's Jump Shear and it barely made an indentation in the metal.

The most common stomp shears max out at 16g which is .059 , mild steel, not 4130.

You might check the FBO”s shear as the blade probably took a pretty big hit.
 
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Links

Doesn't Van's supply a strip of steel for the linkages? All you have to do is cut to length, round the edges, and drill 'em. A hacksaw, a file, and a drill should be the only tools required.

Now, if you're hacking them out of a sheet, that's another issue.

Vans has lots of choices
Link
Link
 
My Van's supplied links with the RV-14 kit were not long enough if you put the rudder bar in the most forward holes. I made new ones using 4130 sheet. Ended up using several Dremel cut off wheels.
 
I got some 4130 strips from Spruce. They make good links and .061" is perfect for engine brackets like the factory. Hack saw and bench grinder to round the ends - keep the temps in control. If it quenches hardness will result.
 
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