This is a great operational question. Most large contractors will not even look at anything less than 1000hp and some are of the thinking, bigger is better, and get the 1200+ horsepower units. It is a small percentage of the market, but there are plenty of those size units sold.
Let’s take a look at it operationally:
- What are you grinding?
- What production numbers do you actually need?
- What is your permanent support equipment used with the grinder?
If you are going to get more horsepower, whether its 1000 or 500 for that matter, you need to support using that horsepower. It could be a chipper just as a grinder:
If you are landclearing, and have 1200 horsepower and filling trucks as you grind for example, you need a loader or skidder or dozer to be able to keep material within reach of the grinder. If you cannot keep the hopper of a 1200 horsepower grinder full, what is the sense in having 1200 horsepower?
If you are producing mulch and regrinding, you need a loader large enough and a pile close enough to keep the hopper full.
What does more horsepower do for you?
- It can grind large stumps more efficiently
- It can grind big diameter wood much more efficiently
- It can produce a lot more mulch on a regrind basis per hour
All of those are obvious, but what is the cost?
Fuel — more of it
Fines — more of them without shearing
More expensive parts and service — bigger parts and more of the Filters
So what do you do?
Do you have the support equipment when landclearing or feeding mulch for example?
Do you have a wood shear that can reduce the larger wood and make it easier for a less horsepower grinder to grind more efficiently? Grinding big diameter wood and big stumps is possible but without reducing the size you are going to get a lot of wood fines regardless of the horsepower.
When producing mulch figure out what your sales volume is and compare using less horsepower to the 1000 horsepower. What is the production difference? What production rate do you actually need? How many hours of production would that be for your sales volume?
Do not purchase a larger horsepower grinder because you need more production for 1 month a year. Plan ahead and inventory more.
Here is an example I used for a customer about a month ago, using a 765HP grinder vs. upgrading to 1000HP:
- $100,000 — Upgrading means you also need a larger PTO and a larger cooling system. So that would be $20,000 a year for 5 years
- Fuel — Without actually tracking each unit at a demonstration, we can only use the max fuel rates of each engine which is approximately a 40 percent increase. That equates to about a $20/hr increase per hour for just fuel.
Parts and Servicing is much more, too. As an example: there are twice the number of filters for the 12 cylinder 1000HP engine.
Production rate with less horsepower was enough to keep the two operators more than busy, so if there was more HP they would run the hopper empty more often
Therefore, in this example less horsepower was producing more than enough to keep a business profitable, and the reduced operational cost helped the bottom line.
Don’t rely just on my numbers — these are assumptions and estimations. Create your own calculator using actual fuel numbers from a demo and then use the production numbers of each horsepower and see what you get.
The fuel savings using less horsepower will be more than enough to pay for purchasing a splitter or shear to make a lower horsepower unit productive.
Most grinders are used about 1000 hrs a year, so a lower horsepower unit that produces 20-30 percent less would have 1200 hrs a year. It’s nice to finish a job in 10 days instead of 12, but if the grinder has nowhere to go immediately after that, what is the real cost?
So, as you can see, there is no simple answer, each company is different, but that is why equipment salesmen like myself bring units out for demonstration so you can get accurate numbers on your materials.
But in any case, if you are thinking of buying a grinder within the next year, buy it before the end of 2017. Next year with the advent of mandatory Tier 4 engines, it will cost you $30,000 to $60,000 for the same engine, same production and the operational cost will certainly increase with the additional emissions parts that will have to be maintained also.
Questions? Dave Whitelaw, The GrinderGuy email@example.com