Banjo eyes for chain

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I am looking to make some banjo eye tie downs for a trailer I am getting I will probably use c channel that will be fairly close to matching up to a 2x8 I have done them before with a hole saw and jig saw for the notch then a 5/16 bit for the end of the notch. My question is, now that I have a plasma will the heat effect the steel strength if I used that to cut it out looking at probably 1/4 chain possibly 5/16 and the channel would be .25 thick at the top.
Reply:http://www.zips.com/Store_Detail.asp...720268&CAT=540  If the commercial units can be welded they probably are made from mild steel I would imagine.Mild steel isn't affected very much by heat, which is the reason it's used for welded structures.  I shouldn't think the minimal heat produced by the plasma would affect strength that much, if at all.  The real good thing about plasma is the narrow heat zone, as opposed to O/A cutting.Personally I'd suggest something in the order of at least 1/4" plate, and optimally 3/8" plate.  I'd imagine the thicker plate wouldn't interfere with the gap between the links, depending on the chain you're using.  5/16 or 3/8 grade 70 should work with the thicker plate.Thicker plate will resist bending much better than channel I'd imagine.  I'm not sure how you design yours though"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Ok great thanks for the info!
Reply:The heat will not have a noticeable effect on strength.....but the shape and roughness of the cut can produce stress risers that can weaken a part. Makes sure your cut edges are smooth!  Picture is of a smooth cut done on 3/8" steel with a Powermax plasma.Jim Colt Originally Posted by mrbacklashI am looking to make some banjo eye tie downs for a trailer I am getting I will probably use c channel that will be fairly close to matching up to a 2x8 I have done them before with a hole saw and jig saw for the notch then a 5/16 bit for the end of the notch. My question is, now that I have a plasma will the heat effect the steel strength if I used that to cut it out looking at probably 1/4 chain possibly 5/16 and the channel would be .25 thick at the top.
Reply:I wish the old cutmate 300 could do that!
Reply:Jim every time I see you post pictures I tell myself I need one if those!!!  One day I will own one for the house.  I love using them when I am at a shop that has one and it is functioning.  Seems a monkey is always the last one to use it before I get to.
Reply:Originally Posted by Scott YoungJim every time I see you post pictures I tell myself I need one if those!!!  One day I will own one for the house.  I love using them when I am at a shop that has one and it is functioning.  Seems a monkey is always the last one to use it before I get to.
Reply:FarmerSamm,The Plasma machine in my shop is not finicky at all. It has been there for almost 7 years (PlasmaCam DHC2 and Powermax85....originally a Powermax45). It has never had a single issue......and operates in 10 degree F weather in the winter here in NH. No boards, no belts.....nothing. Of course I change a torch consumable now and then, and occasionally I set the speed, the amperage or the height wrong.....but the machine has paid for itself many times over!Todays plasma cnc machines....at least the major brands...are extremely reliable, easy to learn and easy to use. here is a picture of a job that made me $800 in 2-1/2 hours. Nice thing is that I could walk away from the machine while it cut about 900 of these parts.Jim Colt Originally Posted by farmersammThe shop I regularly visit when picking K'kins up for lunch has the same problem.  The plasma is usually down.  They're on their second machine in about 2 years.Personally I feel they're wonderful machines, but they're like problem children.  Always something going wrong.  Very finicky machines
Reply:If you do go with a plasmacam get one with the DHC2 Z axis. I just picked one up with the DHC head and I can already tell before I even have the torch on it that the weaker motor is going to give me trouble.
Reply:I had the original model 98Z....it used a tiny z axis motor. Never failed in 6 years....although I had to make sure the sliding mechanism was kept clean and free from slag/dust. The next model DHC had a much larger motor than the 98Z....but again it needs to be maintained. The DHC2 and Samson, 510, and go torch all have a larger z axis drive. It is a bit noisy due to design, but I have never had an issue. with it. Other improvemenst involve the belt reduction drives (much beefier than the early models), the advanced height control (auto calibrates before each cut...senses the surface using ohmic technology), and the software....the advanced design edge is considered expensive by some.....but after using it you will realize it is worth every penny. I stopped using SolidWorks and Corel Draw....all my design and drawing is done with the Design Edge now....even the parts I cut on my other machine! I like the way that PlasmaCam addresses all of the issues with each new revision of their original machine. To me that shows a progressive company that practices contious improvement programs.  It is what I call an entry level cnc machine.....certainly not a three shift a day industrial cnc machine......but for my use it is simply amazing.Don't get me wrong...there are a few other brands of entry level cnc with great features and quality.....I just happen to have this one. I am preparing to build a new 5 x 10 machine using CandCNC.com electronics and Mach software......Jim Colt  Originally Posted by VPTIf you do go with a plasmacam get one with the DHC2 Z axis. I just picked one up with the DHC head and I can already tell before I even have the torch on it that the weaker motor is going to give me trouble.