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HYDRACORE MONTHLY NEWS LETTER BY  Nigel Spaxman

News Hydracore Drills Jan 07

 

As expected we are now quite busy.  We have orders for 5 drills.  Normally January seems to be when we get most of our orders.  We are building drills for some repeat customers and some new customers.  For the first time we are building one of our Manportable Drills with the 4 engine powerpack with our HQ hydraulic chuck.  This drill will have the same hydraulic flow and pressure as the 115HP  John Deere 4045 powered machines we have made.  The control panel and drill are basically the same as on the Hydracore 2000.  This will give the machine a maximum capacity of about 2000 feet of NQ.  The heaviest part that will have to be moved in one load will be about 400 lbs. The engines weigh 340 lbs wet in their carrying frames.  

 

Last month I was talking about RPM and torque requirements for drilling.  I decided to make a bit chart that would show the different sizes and areas of drill bits.  From the size information I have also calculated the bit face areas and core areas.  From this I was able to estimate the bit torque, or at least how the torque from one size bit would compare with a different sized bit under identical operating conditions. 

 

Using this chart might be helpful if you need to estimate how much more torque you will need to drill a different size.  Sometimes on Hydracore drills it is necessary to get a new hydraulic motor so that you can drill with a bigger size.   This chart could help you to determine how much more torque you are likely to need so that you can select a motor with the right amount of extra torque.  The chart even shows the difference you can expect going to a thin kerf bit.

 

If you don’t want to bother with these types of calculations the interesting thing about the chart is that it shows that with each increase in size from AQ to BQ for example, there is an approximate doubling of the torque required at the bit.  This is about the figure I had expected.  If you look at the specifications for many machines you will often notice that the rated capacity in N size is about half of the capacity B size.

 

Geologist could use the chart to figure out the volume of the samples are that come with the different core sizes.

 

The other news from just up the street from here at Boart Longyear is that Doug Searle who was the Manager of the Delta branch here has left Boart Longyear.  I think he has been wondering if he could help us to sell our machines, he knows he could sell a lot more of them.  Really what we need right now is help making the machines.  We can sell all the ones we can make quite easily I think. 

 

Next month I am going to try to make an estimate of the frictional drag of different rod sizes in a similar way to the way I calculated the bit torque.

 

Goodbye, Nigel Spaxman

 
>>>>>>>>>DRILL BIT CHART

 

Here is the first installment of the news at Hydracore.   I am hoping to write something every month so that there will be something new to look at on the web site.  We are always making new things here.  Since this is the first installment I guess it will cover the whole year of 2006. 

 

This year we have made about 18 machines. 

 

We made two of our 200 HP machines with the PQ heads ( Hydracore 4000s), for Geotec S.A. in Lima. These machines are working very well for the customers who are using them.  Many holes have been drilled to depths of over 450 meters of HQ.  I went and visited one of the machines in operation at the Las Bambas mine near Cusco in Peru.  This was a very interesting trip. The altitude where the drill was, was about 4500 meters.  Here once again I found that high altitudes can alter the settings of some relief valves by about 30%.  This seems impossible and many hydraulic experts will tell you it is not true, but it does happen.  I think it is the pilot operated relief valves that are effected.  Also the engines on the drills have the power reduced by about 25% at this altitude.  The main relief valves had to be set down so that the engines would not have to heavy a demand placed on them.  At the same mine site Geotec was operating some of their truck mounted CS 3000 drills.  These drills are huge expensive machines, but it is surprising how little more power they actually have compared to the HC 4000.  In fact the main hydraulic pump on the Hydracore 4000 has about the same flow capacity as the main pump on the CS 3000.  Because the engines on the Hydracore are only 96 HP each, reduced to about 70 HP by the altitude the hydraulic pressure is much lower.  At sea level this drill would have almost identical power to a CS 3000. 

 

The CS 3000 has an amazingly complicated hydraulic system, a cylinder that is installed backwards, and a control panel with all the gauges mounted at a height of about 6 feet. I was not impressed by anything about it except it’s size.

 

We made two of the Manportable machines with the three 30 HP Diesels.  We now mount the hydraulic panel on top of the hydraulic module to make the power pack more compact.  Also we made one machine with three of the Briggs and Stratton Vanguard V twin 35 HP gas engines.  This made a very nice drill.  The engines are light they run really smoothly, and they have more power than the Diesels.  We also started making the panel with a different valve layout that makes operation simpler, and also eliminates the sequence valve.

 

We made quite a few Hydracore 2000 drills this year.  We made two using the John Deere 4045 115 HP engine, for Driftwood Drilling.  They drilled all summer for Kenrich Eskay.  The drills performed very well.  At the end of the drilling season each drill had drilled almost 50,000 feet.  On both drills the original belt was still in use and really looked like new as well.  This to me proves the durability of these Gates Poly Chain 2 belts.  Soon we should be able to get the Poly Chain 3 which is supposed to be even better, not that any improvement is really required.  It is obvious to anyone who has used these belts that they are better than gears or chains.

 

Recently we completed the first Manportable drill with 4 engines.  This was built for Lance Hubbard, of MVP drilling in Ecuador.  We built the drill using the hydraulic module from our Hydracore 2000 drill in order to handle the 33% extra hydraulic flow from the fourth hydraulic pump.  The drill used also our new E head, with the same drive system and hydraulic motor as the Driftwood drills with the John Deere engine.  In fact the hydraulic flow and pressure is about the same as the JD drill.  We call this drill the HC1500.

 

Some of the experiences that I have had this year have to do with rotation speeds for drilling.  Many drillers know these things from experience, but some don’t have the experience.  We have found that for NQ drilling on some projects the rotation speed of 1500 RPM works best.  We found we could drill faster with the drill going this speed than at 1250 RPM.  On another project we found that we could drill faster with the rotation at about 1000 RPM, because the ground was very hard.  Any faster and the bits would polish.  We found that drilling very hard Quartzite HQ size that the best speed was about 600 RPMs.  This speed looked really slow, but it was best. Another very experienced driller told us that the best speed was 2500 RPM.  I thought he was crazy when he first said this but later I realized he must have been referring to the engine RPM.  He didn’t realize his tachometer was not the rod speed but the engine speed.  It is not always best to use the highest speed which the engine horsepower will allow. 

 

Here is a way you can estimate your bit RPM with the Hydracore 1500, 2000 and 4000 drills.

On our drills with the variable displacement motors like the Hydracore 1500,2000 and 4000 an easy way to estimate the speed when no tachometer is available is to calibrate the knob that controls the speed.  To do this you have to find out what the maximum and minimum speed of your drill is from the specification sheet.  On the HC 1500 and 2000 drills this is usually 500 to 1500 RPM.  On the HC 4000 drills this is 500 to 1250 RPMs.  Then run the drill turn the rotation knob in, and find the spot where turning it in more makes no difference.  Scribe a line on the knob that points straight up.  Then turn the speed down until you find the spot were the speed is as low as it will go.  Mark the panel in this spot.  Usually the knob will have to be turned about 1 ½ turns.   Use the torque gauge to help find these spots.  Once you have these spots marked you can estimate the speed easily, based on rough proportions of the high and low speed.  For example on the HC 2000 if you have the knob half way between fast and slow the speed will be 1000 RPMs  Also it is easy then to tell your cross shift what setting you were using. Just refer to the position like a time for example 11: 00 would be almost full speed.  

 

It is worth thinking about the torque requirements of different sized bits as well as the speed requirements.  The torque I think should be proportional to the area of the cutting face times the average distance the face is from the center of the bit.  If the torque used on a BQ bit for example is 120 foot pounds.  This being just the bit torque then the torque on other bits could be calculated as a percentage of that size. 

 

I will write more about this next month, when I will also add a very interesting chart about drill bit sizes areas and torque requirements.

 

Nigel Spaxman