Trenchers on Skid Steers - Advice sought

[Squizzy246B]

I have to eat my words about "we will never use the Hi-Flow capability on the new 248B" because we now have a commercial client who needs about 8 miles of trenching done.

We have no experience with trenchers other than hiring ditch witches. I can hire a trencher from CAT Rental but we are considering buying one.

This is one I have considered:

http://www.digga.com.au/trencher_2bigfoot.htm

Whats the "in's and out's" of these things...they look like something you could spend a lot of money on??. What are they like to operate on a skid??. What should we look out for when buying one.....should I just use the bloody excavator . The guys at Digga-West said the 248B hydraulic pressure at 280bar is too high for most of the motors (around 240 bar optimum) and we would have to go with a more expensive motor???.

We also considered getting a trencher for our new 301.8C but I'm guessing that would be slow as slow can be...then again...it will be hourly hire work TIA

Oh, just must add that most of our work would be in coastal sands although we do hit a lot of limestone and occaisionally have to work in gravel.

 

[CascadeScaper]

We have a Cat T9B trencher and it works great. We have it set for a 4" wide trench, we use it exclusively for runs of irrigation lines. We paid $5,000 for ours, but a high flow model could be $7K-$8K or so. Some things to consider:

1) Soil conditions - If you're working in very rocky soil, you might order "shark teeth" on the chain. Most chain setups will run every 3rd or 4th tooth a shark tooth and in turn, they dig through rock much easier. However, they don't leave a very clean trench, so it's advised to use as few of the shark teeth as possible to get through the conditions.

2) Width of trench - This can be changed by using spacers, but we ordered ours from the factory setup for 4". Getting a somewhat general spacing will allow the best operating efficiency, i.e. you don't want to be digging a 10" wide trench for 2" of pipe, you end up digging way too much and it takes forever.

3) Depth of trench - We can run down about 4 feet with our trencher, but the larger models can go down as low as 6 feet I believe. We rarely go below 3 feet, so analyzing how deep you need to go is somewhat important as well.

I'm sure there's something I'm forgetting, so if you have anything else you want to know, let me know. I think that Digga trencher isn't worth the money spent, the chain looks very, very cheap and that's the biggest investment in the whole piece. Forget the motor, the auger, it's the chain setup that makes or breaks a trencher. For what it's worth, we've been very happy with our T9B. Grease it every 4 hours, keep the chain tensioned properly and these machines perform like you wouldn't believe.

 

[Squizzy246B]

CS, thanks for the comprehensive reply. The Digga salesman did say the chain shown is just a cheapo. I got all their sales glitz in the mail today and they are recommending "Xtradrive" Inertia Power system and a Tungsten Carbide chain...all available as Optional Extras of course...for the 248B. They are talking $4,500.00 Aus for the unit and about $1,800.00 for the TC chain with spacers. How much the Heavy duty motor and gearbox will cost for the 248B is not yet clear. The Digga units will run to 3500 psi whereas the 248 is at 4000 psi.....I wonder if I can get that adjusted on the machine???.

The "Super Hydrive system they sell has 3 points of contact for the chain which keeps the chain running in air and not running in the boom; supposedly they don't wear as much.

I know that their gear is pretty good as many manufacturer's (including Toro Dingo) use the Digga planetary drive and gearboxes.

 

[kuykendall_exca]

How do they compare to a 40 HP ditch witch as for as feet cut? Considering both machines are running in identical soils?

 

[bill5362]

Squizzy246B Here is what I have experienced in a test of the trencher attachments. I have tried the Bobcat LT414 which has hi flow. The soil we have around here is 6" of top soil and clay, and of course rock is an issue sometimes. For what we do I wasn't very impressed with the production. We tested one for a week and for silt fence 6 to 8 inch in worked very well, high production. But at 4' in depth and the clay in the soil it would take over a minute to get one foot. We purchased a used case 760 trencher with 70 hp, and a 5ft boom, and paid $12,000 for it. The production out of the case 760 is 5 feet per minute at 4' in depth. Hope this helps in making a decision.

 

[Big Dazzler]

Hi Squizzy

I have one for my rc30 and it is great. Used mainly in clay and sandy stuff no probs at all.

Just ungainly for transporting around is all.

Should be about $5000kish.

Get the tungsten chain.

 

[KSSS]

There are a lot of OEMs out there that build high flow trenchers. There are other options such as hyd. offset, auger which you would want if you going to any depth.

Hyd. hp is the key to production, weight of the power unit also helps but the key is to let the unit do the digging without trying to push the trencher through the material. A combination chain works well in semi rocky soil. The downside to these chains are the cups are what remove the dirt not the carbine points so a 50/50 chain reduces ability to clean out the trench. The upside is it helps cut through the material. So its a trade off. If your in agreeable soil, going with a tungsten or carbide chain your giving up some productivity. The guys that do a lot of this have different chains for different soils. The production differences make it worth while to invest in different chains.

I owned a 360 trencher. Good machine. A couple options I would consider is try finding a good used dedicated trencher, complete your job and resell it. You might come out even on the deal and use the trencher at a no cost to you depending on what you find for a used trencher. The option would be to rent a trencher for the period of the job, sucks giving money away like that but sometimes its the best answer.

Trenching is neater than hoeing the trench, but crossing utilities usually still takes an excavator or a backhoe equipped trencher 660-760 type.

I would try and rent a high flow trencher and see what kind of production you can get in your conditions. The nice thing about buying the attachment is after 8 miles you should be able to cover the cost in the job. If its too slow at least you know that the attachment is not an option.