Im going to sound like a contrarian here but here are my rapidly typed thoughts. I have owned 9, 12 and 18 in chippers.
An 18 in is definitely a night and day difference from something smaller but they are way more expensive.
It's not hard to find a 12 in starter chipper for under 15 grand, which is 1000 times better than stomping a trailer. It might be a good option to start out with and work your way up to an 18 inch later unless you have beaucoup bucks to spend in the meantime. Also tough if you need a loan cost upwards of 8% interest now.
We have a 12" gas and 12" Altec diesel. Both are comparable. The difference is how much you spend when you turn the wrench.
Not so serendipitously, we recently blew engines in our 18" vermeer diesel and 12" woodchuck gas. The cummins in the Vermeer is costing me well over 10k to rebuild. The old woodchuck with 300 ford engine was only about 3k for a used one installed.
Also, I bought the vermeer about a year ago for only 16k, which seemed cheap at the time, but I'm now into it around 40k for a 20 year old machine.
The original question depends on how much your willing to spend and if you have the work volume to justify buying something bigger.
Also for what it's worth, the bandit you rented might have had some issues like dull knives that reduced performance. You might be surprised what a well maintained 12" can do.
I wont be offended if you disagree. These are just some of my unfiltered thoughts based on recent events.
My rule of thumb is NEVER buy a used diesel anything if it don't come with service records. Reason being is, when owners want sell something, they tend to get lax on service and just keep running it. I'm glad I work for my Kubota dealer part time as it allows me to get parts for my diesel tractors at dealer cost and the things I need intervention from the techs there, I get done for basically no cost. I do my own services but for major work like valve adjustments, I put them in the shop and have them do it. Kubota's all have complex multi valve sets (even the older ones like I have do), so overhead adjustments take special tools and expertise that I don't have. My Kubota dealer is also a certified Cummins and CAT servicing dealer for industrial diesel engines. Don't sell new, just fix them. I did buy one used M series Kubota and lucked out on the engine. Cummins especially are easy to work on and reman engines are plentiful. Not so much with Cat and I have no idea about the others like Vo-mack or Isusu.
As it was I had to put about 5 grand in mechanicals anyway, Stuff gets old like hydraulic hoses and valve assemblies, least the engine was good, Gas don't work for farming today. Has to be diesel and the new diesels are all common rail, computer controlled and very touchy and you cannot do **** to them either, except change the fluids and hope they don't break down and need service because you cannot do anything to the, all dealer intervention and none of it is a cheap date either. The dealer I work at, the customer labor rate is 135 per hour, Just fortunate I work there and the lead tech (Kubota) and I are good friends and we hunt and shoot together.
Whatever you do, run from anything John Deere, especially with industrial engines. I have a JD turbo charged 4 cylinder diesel in my standby generator but it's a Pre 4, thank God. mechanical injection and no after treatment and so far (15 + years no, no issues other than maintaining it.). JD has over complicated all their engines and made them not user fixable.
I will tell everyone about Kubota's new reman policy and that is, if you have major engine damage, like a tossed rod or major mechanical failure, Kubota WILL NOT PROVIDE A REMAN ENGINE until a dealer or you provide certified documentation that the original motor has been destroyed and that means the head has been removed and the head deck has been grooved with a grinder across at least 2 bores with an abrasive grinder, 1/4" deep. No exceptions either. Used to be that you could drill a hole in the block, no more and that includes failure of the emissions hardware on new engines too, under warranty or not.
I know, remember I work at a Kubota dealer part time so I know most all the skinny's and the returned engine must be returned with ALL it's internal and external components as well and that includes all the external emissions components as well like pre treatment stuff, SCR cannisters, elements, common rail pumps and even the ECM..
Same applies to Deere, Not sure about Cummins industrial engines but I do know that Cummins has a bad habit of stretching head bolts and pulling the threads out of the head deck. been charged with the task lately of tearing them apart, pulling the heads, extracting the head studs and installing Helicoils and replacing the heads and new head studs and it's an involved and dirty job too and time consuming as well. They are also bad at turbo failing on the hot side which almost always involves a minor to major rebuild because the hot side compressor wheel goes into the engine and eats the head up or destroys pistons, So long as they don't toss a rod through the block, they can be rebuilt in the shop. Tossing a rod requires a reman engine of course.
Kubota as well as Deere and the others USED to build good engines, not today. Even a reman engine will contain Chinese or Indian parts. Cummins and Cat now have their blocks cast and machined in India and assembled with Chinese internal components and I know as I get to see them before installing. World class economy hard at work, also known as cheaper labor and more profit.
When I worked at the WesternStar dealer, we saw little major engine damage, just tune up's and replacement of exhaust studs and spacer plates on Cats and Cummins had fuel pump issues from the now defunct ceramic followers falling apart which always entailed a new reman engine because the ceramic followers ate the engine internally and DEEC engine (Detroit Diesel 4 strokes) had to have the OHC cam bearings replace at every tune up (valve adjustment job) but those were pretty easy, being OHC, but that all changed when the gummit got involved and the emissions crap started.
I retired just before it got stupid. Glad I did as I know all the mechanics that work there and I was told that over 77% of all the work done today, warranty or not, involves engine remans or engine rebuilds, caused by emission control failure and today, they cannot fix anything unless the computer is plugged in and all the fail codes downloaded to the engine manufacturers and THEY determine what caused the failure and what is consider what is warranty and what is on the owner.
Remember, emissions controls and all ancillary emissions parts carry a 5 year gummit mandated warranty but it's up to the manufacturer entirely what the root cause of the failure was and what they will warrant and what they wont and of course they always lean towards no warranty so you get to eat the cost they can put it on you and they do as much as possible and that applies to Cummins and DDEC as well as Kubota and Deere and all the rest.
I just happen to rebuild the 'One Boxes' on DDEC and Cummins engines for the dealership. The welds on them (boxes are stainless 'low grade stainless') and the input bungs and output bungs that feed coolant and DEF into them, corrode and must be replaced and that involves TIG welding replacement bungs in and welding on replacement plates where the corroded bungs were (those come from the manufacturer of the one boxes as a kit, but must have the old failed stuff removed and replaced and TIG welded in so I have to split the one box to access them and then TIG weld it back together and TIG weld the new parts in. That takes time and costs money. I charge a measly 75 bucks an hour for that job. No hard, just takes time and all the welding must be pressure tested as well. Keep in mind that a new one box retails for over 18 grand and they all have them no matter what engine is in the truck.
If you drive down the road and a newer truck passes you, look on the right side by the front fender for a heat shield. Under that is the one box. All the emissions crap (DEF injection, SCR and reburn cannister is inside it), all in one place and doomed to failure at some point thanks to your EPA and it fattens my wallet, regularly. I have to be AWS certified to weld them too and I am and I have to provide that documentation with every one box I rebuild as well and a copy of that certification stays with the paperwork provided to the owner, once the rebuild, repair is complete and the owner is on his way, with a much lighter wallet I might add. Nice and fairly lucrative side job for me. Of course I have to eat the consumables, it's part of the per unit cost. shielding gas,100% argon, plasma consumables, yearly certifications(thank the Lord, one of my infrequent customers and he can certify me for exotic metals TIG welding) and provide the certification which has to be renewed yearly per Federal law.
I know this is al long post, sorry about that but it's what I'm familiar with....
