I have a question concerning use of the offset swing/dig feature on many of the smaller excavators. The present machine that I see this occurring on is a JD 50G. I have quite a few hours on many different excavators both large and small though by no means do I classify myself as an accomplished operator. Having said that, (I always liked that saying!) I have been watching an operator who uses this offset feature continuously in everything that he does with the excavator. Ditching, digging, loading trucks, etc. in all applications. He says that this gives him better viability, control, etc. but I can't help but think it must be hard on the pins and bushings when always operated this way. Some of the digging is very hard and rocky. He always operates with it in full offset mode. Am I wrong in assuming this or is it an acceptable method of operation with no stress on the machine? I do know that it is a bit of a PITA to back into the bucket with the truck as it doesn't look right in the mirror! Any feedback is good regardless of opinion!
While I don't know the negative mechanical side affects from continually digging offset, I do know two things for sure. 1-You will lose some horizontal reach. 2-You will lose some of your lifting capabilities due to the counterweights physical location being changed in relation to centerline of the machine. I don't know what you gain from running the machine offset all the time, nothing in my opinion. I've been in tight spaces with mini's and you are looking through the side windows constantly when you are offset.
I worked with a company once plowing snow, and hauling salt. They ran, and still run mostly junk. They bought 2 1982 GMCs with 290 Cummings. These were probably the last new trucks they ever bought. Both trucks had Jake brakes. Being used to trucks without air brakes, the drivers used the jakes all the time. One of the owners because he was not familiar with the Jake setup figured it had to be hard on the engine. He went as far as having them removed. Guess what I am saying is just because we are not familiar with features on equipment, doesn't mean it hurts to use it.
I have a long stick E50 bobcat at work that I run 95% of the time when needed. I have to use the off set 40% of the time working row, ditches, slope work, storm water, utility work. Like said above it is very unstable working it offset with the weight of several different mow heads and a full power-tilt and 50" plus cleanout bucket when working it at max reach and depth. It would be nice to say I didn't need the offset function but it is the most productive/universal attachment when working in so many job conditions. I will say you can hear the stress in the machine while working it but this is the reason it was purchased to get the job done and move on. It is a unforgiving machine with the off set being used and I don't allow often other personal to be put in the situation to have to run it like that. It would seem that digging like the guy spoken above would have a lot of twisting and turning with the tracks in straight line digging, (that would drive me nuts) if one of my staff did that. I don't see a problem in off set digging if you need it but centered up gives the most stability. We just had are timberline 10" tree shear delivered last week, waiting on some hose extensions, for the hyd system hookup, it's weight is around 650#, this should be interesting in 20-30' row's.
When talking off set swing, do you mean the back hoe type swing, or the knuckle boom....We have an 85 John Deere with the first type I mentioned. The guy running it uses it a lot, and the machine has almost 9000 hrs on it with no problems yet. He finds it heavy on the front with the boom mounted ahead of the cab, and finds using it kinked to some extent takes some of the front heaviness away.
Thanks for the input. This fellow runs it with the boom as far offset to the right as possible. So looking out the front window the boom is always far right. He looks out the side window all the time, which I would think has less visibility than the front windows, and has to be hard on the neck muscles. I've never seen him operate with it in normal - straight ahead - position. Different strokes for different folks I guess, but when you are handling bigger rocks and stuff vision must be important. No Offset here folks!
I would imagine it would be hard on the swing gear and motors, the digging force would naturally want to pull the boom to a neutral/centered position. The swing brake is always holding back as you're digging. The offset boom changes a lot of fulcrum points in the geometry of the machine as well. Plus to give you better visibility I would prefer to have the boom to the left, I.e., looking out the door or left side from the seat, it does give a better line of sight as you are on the left side of the boom in that configuration.
The smaller Cat minis, and maybe others, have the boom offset a bit from the center of the machine in order to accommodate the cab. I suppose I could understand offsetting slightly with the controls to center the boom between the tracks, or to improve visibility, but other than that the performance of the machine will be diminished, wear and tear will be greater, and the job will take longer. I would not allow that on my job unless it was necessary because of excavating next to a building, etc.
On the smaller mini's when one must offset, the machine will try to slide the tracks to a new position in order to make a straight pull and if the track is sort of locked into the ground it will lift the swing motor relief and try and straighten out the cab.....tis necessary to try and dig downward instead of pulling and use the teeth....keeping a generator and a small water fire extinguisher for the sparks from a small angle grinder with a cutoff wheel to keep those forked teeth super sharp is the least one can do when this is the only machine that can access the area.