Stump Grinder Math

[Topbuilder]

A couple years ago I jumped into the stump grinder business with both feet. It seemed like a natural fit, I already had the truck and a couple different gooseneck trailers. I had a shop and all the tools I would need. I worked at a farm equipment dealership for 20 years so I had the ability to make most of my own repairs.
I bought two used Raycos from the same individual. One tow behind and a RG-50. With the purchase I got a 5 minute operating lesson and a 10 minute talk on the business side of the business... How he charged jobs. Not knowing any better, I decided to use his pricing system, which was a standard set up fee + $8 per stump. My first job was 20-30 fresh cut pines ranging from 12 - 30". By the time I completed that job I knew that I had bid the job like a hobby, not enough to feed a machine hungry for fuel , teeth and an ever growing list of expenses...
I left that job headed to another big job. I figured out what I had to make to cover expenses and have something left over. I bid the next job by making mental calculations of how much time it would for each stump x my new "rate". The guy freaked. He was used to paying $8. I walked him over to the bigest stump on the job. (the one in my avatar) It was a 72" pine. I explained to him that stump was going to take me 3 hours, and it was going to cost me $15 in fuel. He was a common sense guy, I had no problems with that job or any job after that.
Have I done every job I have bid? No. Not because I over charge, because there is people out there willing to undercut even if it means they don't make money.
Anyway, I said all that to say this - I needed a way to estimate the valure of a 18" stump verses a 48" stump. I really did not want to use the "per inch" formula I had seen others use. My area would not support pricing like that anyhow. I started with area... a circle is 78.53% of a square. I'm no math wiz but I can deal with that. So a 24" stump is 1.78 x larger than a 18" stump. OK that was shocking. A 36" stump is 4.01 x larger than a 18" stump.

So, if your rate for an 18" stump was $15 then:
24" $26.74 1.78 x larger
36" $60.17 4.01 x
48" $107.04 7.13 x
60" $167.30 11.15 x
72" $240.93 16.06 x
84" $327.86 21.85 x

Does a 48" stump take the same amount of time as a 7 18" stumps? Probably not. When you factor in moving from one to the other and other variables. But it gives me a starting point. When you explain to the customer that 36" stump is not two 18" stumps, it's four 18" stumps they understand the pricing a little better.

 

[treecutterjr]

That math makes since but I made a craigslist ad charging $3.00an inch and people have been eating it up. Are those your actual rates or just for demonstration purpose?

I just got $150 for a 4 ft diameter oak stump 2 days ago cut fairly flush. I just picked up 2 stumps for $450 this evening. They were about 6ft across.
I understand the math of what you are saying but the inch think seems to work for me and the customers like it because they can have a rough idea of what it will cost before they call and it's basically a done deal.

24" =$75
36" =$108 round down to $100
48" = $142 round up to $150
60"=180$

After about the 6 ft mark it can get questionable but so far so good. I don't plan on doing any 10 ft diameter stumps anyway.



Sent from my SM-N900T using Tapatalk

 

[c5rulz]

I am not a stumpgrinder, but TreecutterJr.'s system of so much an inch gives the customer a pretty good idea what they are getting into. Explain you are going out to the edge of the root flair rather than the actual diameter of the stump in order to do a good job.

 

[Topbuilder]

That math makes since but I made a craigslist ad charging $3.00an inch and people have been eating it up. Are those your actual rates or just for demonstration purpose?

I just got $150 for a 4 ft diameter oak stump 2 days ago cut fairly flush. I just picked up 2 stumps for $450 this evening. They were about 6ft across.
I understand the math of what you are saying but the inch think seems to work for me and the customers like it because they can have a rough idea of what it will cost before they call and it's basically a done deal.

24" =$75
36" =$108 round down to $100
48" = $142 round up to $150
60"=180$

After about the 6 ft mark it can get questionable but so far so good. I don't plan on doing any 10 ft diameter stumps anyway.



Those #s are for an example. You can adjust to fit your needs by changing the cost of the baseline ("18") stump. I've been bidding based on the amount of time I think it is going to take or in some cases is is easy to go with a "per stump" rate. Sometimes I come up short. I am trying to make create a system where I am being fair to the customer and to myself. It also depends on the level of clean-up... grind-and-go vs full chip/dirt separation and clean-up. I would say the #s in my example are for just grinding. The level of clean up has to be added in after.

But, if you do the math on my example vs the per inch system it would appear the per inch is based on ease of bidding, Not really based on the job at hand. If there is a coralation between grinding cubic inches = time = $, then my example comes out to .0591 cents per square inch. A 24" inch stump being 452.33 square inches. That same stump under the inch method is .1591 cents per square inch and the larger the tree, the less money you make per inch.
@ $3 per inch: @ rates in example:
24" .1591 cents per square inch .0591 cents per square inch
36" .1016 " " .0591 " "
48" .0795 .0591
60" .0636 .0591
72" .0530 .0591
84" .0454 .0591

I've been grinding for three years. I cannot come up with any reason I would want to grind a 6' stump at one third the rate of a 2' stump. If anything it should be the other way around. Raking that mountain of shavings (several times) is being done for free.
It seems the same loss is being realized by tree cutters using this system.

Just playing with #s and thinking out loud. Where am I going wrong?

 

[Topbuilder]

Sorry, it looks like my columns got crammed together.

 

[treecutterjr]

I have a plow on the back of my grinder and now I hardly ever take a rake with me. Push it up, blow and go. I don't hauI the chips/mulch or its extra. the inch method is super. I can't realistically make a run for a $25 stump & neither can you.
And I would say ease of bidding is definitely a plus. If you didn't have to bid the stumps, Only go do them, You would save tons of time and time is money. You make more per square inch based on the inch method. We are in business to make money. It's easier for the business. Easier for the customer. Sounds like a win win.
And speaking to your square inch point you just add in limits/levels. Stumps 1 ft. To 6 ft. $3.00/in
Stumps over 7 in. = $3.50/inch or $4.00 or $3.75.

Ease of bidding is the whole point to my method.

That's what every other "real" trade does. That's whya plumber can say i can put in so many feet ofpipe for this amount bang. A tow guy says how many miles are you going? Hers the price bam. Even the lawn guys can bid your yard with out seeing it. Just give them the measurements.

That's what the inch method does for stump grinding.

Sent from my SM-N900T using Tapatalk

 

[Topbuilder]

The problem is in our area the inch method would have you at home watching tv.
I bid a job yesterday with 28 pines on three acres, average 20". That would be a $1700 job @ $3 an inch. Never happen here. my bid - $600 . If i'm lucky, I'm in and out in 6 hours.
I know other areas will support that rate, $285 per hour... not here.

 

[climbhightree]

If you Estimate by inch...how does this account for depth of grinding (4" or 12" deep)? What about surface roots, or ground humps due to stump flare? Softwood vs hardwood?

I typically bid on a per hour basis, with an minimum charge.

Sent from my SAMSUNG-SGH-I537 using Tapatalk

 

[climbhightree]

Then you got issues like rocky ground, or metal, that destroy teeth...therefore bid accordingly. Also ease of access.

Sent from my SAMSUNG-SGH-I537 using Tapatalk

 

[Mowingman]

I would not even hook up my trailer, let alone leave the driveway for most of the prices those above have quoted.
I don't price to lose money or break even. I would rather leave the machine in the trailer and set at home reading a good book.
Jeff

 

[luckydozenfarm]

I like to think of the pricing of your products or services as the same as turning the carb screws when tuning up a saw. You turn the screw rich (higher price) the saw (business) will stumble and fall on it's face. If you turn it too lean (lower price) the saw (business) will overwork itself, overheat and blow up. And, like a saw the adjustment will have to be made on a regular basis. Plus the ear for tuning a saw or business comes from experience. So I would suggest you start out making proposals that are netting you about 90% of the work and go from there.
I also run a mechanic shop and I like to keep it at 95% capacity. If I'm at 100% I wonder if I'm not pricing high enough to be efficient. Just a few thought from a business owner.

 

[OLD MAN GRINDER]

The problem is in our area the inch method would have you at home watching tv.
I bid a job yesterday with 28 pines on three acres, average 20". That would be a $1700 job @ $3 an inch. Never happen here. my bid - $600 . If i'm lucky, I'm in and out in 6 hours.
I know other areas will support that rate, $285 per hour... not here.

Exactly u would be at 21.42 per stump, I probably would have to go to 15-17 to get the job here, stump grinders
everywhere, just bid 47 stumps at 750 or 15.95 per stump, all sizes.....

I shoot for 100 per hr, wish I could get the prices they do other parts of the country, but we would starve to
death down here at those prices, inch price down here would get u laughed out of the neighborhood, I look
at the job figure about how long it wil take and multiply by 100.00, I should be able to do the 47 stumps
in 7 hours so 750.00 is my bid, when people call and ask price per stump I just tell them 10.00 and up, for
an accurate price I have to see the job, a 3 ft sweetgum could have roots out 10 ft all around, etc....

Bob.....

 

[marne]

...I shoot for 100 per hr, ... I look at the job figure about how long it wil take and multiply by 100.00, I should be able to do the 47 stumps
in 7 hours so 750.00 is my bid...

Same here but around 140$. Prepare an excel sheet, find out how long your grinder needs for a gal of stump (this is the only truth), multiply with your rate/hr, calc down to $ per inch, easier for the client to understand and compare.
In avg I end up with 3$ per in.

Sometimes you win, sometimes you loose, even when you get the job.

 

[Topbuilder]

If you Estimate by inch...how does this account for depth of grinding (4" or 12" deep)? What about surface roots, or ground humps due to stump flare? Softwood vs hardwood?

I typically bid on a per hour basis, with an minimum charge.

Sent from my SAMSUNG-SGH-I537 using Tapatalk

Yes, that is really what we have to deal with is cubic inches or cubic feet. If you do the math in cubic inches it makes bidding by the inch seem more flawed. All those conditions contribute to the final job. I'm just working on a baseline for me, my machine , my area. Sometimes when bidding "per stump" on a job where the average is fairly consistant, I will give a larger stump or one with surface roots , the price of 2 or the price of three stumps in the group. Your power of your machine really comes into play. If the stump is an extra 6" above ground level that can make a big difference for the smaller machines. They are going to want it cut or cut it lower themselves. The way I look at it ,unless it is really faster to saw cut it I'll just grind it. Price it in either way.

I finished my $600 job in 5 1/2 hours trailer to trailer. Customer is happy. I sold two days of work with my boxblade tractor cleaning the place up. That's a good day...

 

[Mowingman]

Up here in north Texas, I have been able to hold to a rate of about $200.00/hr, trailer to trailer. My minimum is $75.00 in town and $100.00, outside of town. It is getting tougher though, as several people are renting handlebar grinders and doing $100.00 jobs for $25.00. However, I often get hired to go back and clean up the messes they leave behind.
Jeff

 

[OLD MAN GRINDER]

Up here in north Texas, I have been able to hold to a rate of about $200.00/hr, trailer to trailer. My minimum is $75.00 in town and $100.00, outside of town. It is getting tougher though, as several people are renting handlebar grinders and doing $100.00 jobs for $25.00. However, I often get hired to go back and clean up the messes they leave behind.
Jeff

I run into people all the time that were going to rent a grinder until they see the price, I tell them I can do in 15 minutes what it would
take them hours with a rental, some even tried the rental and then they call me when they see how much work is involved using
one of those low power rental units, don't see how anybody could make any money using a rental unit..

By the way Bandit is going to be having an open house at the old poston dealers, I think may 2nd not sure, web site should
have exact date, may go to the one in pearland to see bill poston b4 he retires. get some free bbq...

Have a great one..

Bob....

 

[Mowingman]

I wish I were closer. I got an invite to that, but 300+ miles is just a little too far. Enjoy my share of the BBQ.

I run into people all the time that were going to rent a grinder until they
see the price, I tell them I can do in 15 minutes what it would
take them hours with a rental, some even tried the rental and then they call me when they see how much work is involved using
one of those low power rental units, don't see how anybody could make any money using a rental unit..

By the way Bandit is going to be having an open house at the old poston dealers, I think may 2nd not sure, web site should
have exact date, may go to the one in pearland to see bill poston b4 he retires. get some free bbq...

Have a great one..

Bob....

 

[066blaster]

Looking into a used vermeer 252 are they decent? Can they handle a 36 inch stump

 

[OLD MAN GRINDER]

Looking into a used vermeer 252 are they decent? Can they handle a 36 inch stump

Yes, I had one 27hp, just takes a while, had yellow jacket teeth, good machine but you would not want
a steady diet of large stumps with it......keep belts tight, sharp teeth and it does a good job....

 

[066blaster]

Yes, I had one 27hp, just takes a while, had yellow jacket teeth, good machine but you would not want
a steady diet of large stumps with it......keep belts tight, sharp teeth and it does a good job....

The guy put a 18 horse on it. Will it work?