All three figures are yours. The one that varies most is the third, posts per hour; that is why, further down, the calculation is also done per full working day, which does not depend on it.<\/p>\n
For the example we use sample figures, which you should replace with your own: labour at \u20ac15 per hour per person, two people working and 12 posts driven per hour between them. Driving works out at \u20ac2.50 per post. Over an 8-hour day, about 96 posts and \u20ac240 in labour.<\/p>\n
The costs nobody counts: the broken post and the split head<\/h3>\n
On top of the labour bill come three items that hardly ever appear in the budget:<\/p>\n
- \n
- The split head.<\/strong> The sledgehammer blow crushes the top of the timber. Water gets in through a split head, and a post that takes in water rots sooner. You do not pay for it today: you pay when it has to be replaced.<\/li>\n
- The leaning post.<\/strong> If the post goes off line, it has to be pulled out and started again. That post usually ends up discarded, and the work of driving it has been paid for twice.<\/li>\n
- The drop in output.<\/strong> Posts in the last hour of the afternoon are not driven at the pace of those first thing in the morning, nor as straight. Fatigue is a cost, even if there is no invoice for it.<\/li>\n<\/ul>\n
If posts are discarded on your farm, that percentage, applied to what each post costs you, is money being lost today without anyone seeing it.<\/p>\n
The same job with a petrol post driver<\/h2>\n
With a stake and post driver<\/a> running on petrol, the work changes in something more important than speed: it becomes a one-person job. Whoever held the post is free for another task, and that halves the multiplier in the formula.<\/p>\n
The Farmer 100X weighs 18.80 kg and strikes 1,500 to 2,200 times per minute, with an impact energy of 43.3 to 58 joules depending on the engine. That frequency is why one person gets ahead with the work: the post goes down through an accumulation of rapid blows, not through the force of each one.<\/p>\n
![\"Iberfence](\"https:\/\/iberfence.com\/wp-content\/uploads\/2026\/09\/clavadora-postes-iberfence-farmer-100x-frontal-768x768.webp\")
<\/figure>\nWhere it shows most is with posts that resist by hand. Acacia is the typical case: a dense, sinewy timber that lasts very well in the ground, which is why it is so widely used in vineyards and livestock fencing, but driving it with a sledgehammer punishes the head of the post and the person swinging. With rapid blows, the post goes in through accumulation and the head arrives intact.<\/p>\n
And not just timber: the Farmer 100X drives any post that fits its nozzle, whether metal, timber, plastic or PVC, such as the L-shaped iron posts common in fencing and perimeter protection. The included adapters are changed without screws or additional tools: unscrew the collar, fit the adapter and screw it back on.<\/p>\n
The calculation is the same, with two new variables: fuel and the payback of the machine.<\/p>\n
Output by ground type<\/h3>\n
Output depends on the ground you usually work on:<\/p>\n
- \n
- Loose or cultivated soil.<\/strong> The post goes in without resistance, and the pace is set by the time taken to position and plumb it, not to drive it.<\/li>\n
- Compact soil or dry clay.<\/strong> This is where the striking frequency makes the biggest difference over the sledgehammer. Check the depth reached on the first posts.<\/li>\n
- Ground with small stones.<\/strong> The rapid blows push small stones aside and the post advances without prior digging.<\/li>\n<\/ul>\n
In every case, the machine needs one person; the sledgehammer, two.<\/p>\n
Fuel consumption per day<\/h3>\n
For the example, with the Iberfence IBF-37 engine, we take the maximum consumption given on the Farmer 100X product page: 0.71 litres per hour. Over an eight-hour day that is about 5.7 litres; at \u20ac1.60 a litre, just over \u20ac9 of petrol a day. It is the item most overestimated before buying and the one that weighs least afterwards: around 7% of the cost of a day with the machine, while the remaining 93% is the person operating it. Use 92-octane petrol or higher.<\/p>\n
The break-even point: how many days it takes for the machine to pay for itself<\/h2>\n
The soundest way to do the calculation does not depend on how many posts you drive per hour: it compares the cost of a full working day. By hand you need two people; with the machine, one. It is enough for the operator with the machine to drive at least as many posts as the pair with the sledgehammer:<\/p>\n
Days to pay back = machine price \u00f7 (cost of a day by hand \u2212 cost of a day with the machine)<\/strong><\/p>\n
Using the earlier example, a day by hand costs \u20ac240: two people at \u20ac15 an hour for eight hours. A day with the machine costs \u20ac120 for one person plus about \u20ac9 of petrol, that is, \u20ac129. The difference in favour of the machine is about \u20ac111 per day. The wage and fuel price are assumptions: replace them with your own.<\/p>\n
Example with the Farmer 100X and Iberfence IBF-37 engine<\/h3>\n
The Farmer 100X post driver<\/a> is manufactured by Iberfence. With the price published on its product page for the version with the Iberfence IBF-37 engine and a saving of \u20ac111 per day, the machine has paid for itself in fewer than ten working days. From then on, every day is a saving.<\/p>\n
With Honda GX35T or GX50T engine<\/h3>\n
With a Honda engine, the break-even point is around twelve working days:<\/p>\n
\n - Compact soil or dry clay.<\/strong> This is where the striking frequency makes the biggest difference over the sledgehammer. Check the depth reached on the first posts.<\/li>\n
- The leaning post.<\/strong> If the post goes off line, it has to be pulled out and started again. That post usually ends up discarded, and the work of driving it has been paid for twice.<\/li>\n
![\"20-45,](\"https:\/\/iberfence.com\/wp-content\/uploads\/2026\/09\/adaptadores-acople-reductores-farmer-100x-768x768.webp\")
<\/figure>\n