Choosing the right Mag Drill
Nathan Ford, Area Sales Manager for Fein Power Tools in the UK, discusses what you should look for when purchasing a mag drill, the applications some can now achieve, and the kind of accessories available in the market. Not only that, but he provides some further information on health and safety features, and concludes by briefly covering cordless/compact mag drills, new into the UK market.
Magnetic core drills or “Magdrills” for short are an essential tool for anyone involved in the production and installation of structural steel. They can also be a handy addition to the tool kit of anybody looking to drill larger diameter holes, which would be labour intensive and time consuming with traditional drilling methods. Core drilling is an extremely efficient process which is faster, quieter and more accurate than twist drilling. Core drilling requires no predrilling or switching over of the tooling, and so drilling times can be reduced by over 50%, with minimal physical effort by the user.
Choosing your drill
The first decisions to be made when buying a Magdrill is the capacity of the machine and what size hole are you likely to be drilling? Next, consider what thickness material you will be drilling? An obvious question yet if you are buying a drill with a 30mm max capacity and on your next job you need to drill a 35mm hole it may have been worthwhile buying the model up from the original machine. The price difference will have justified itself when you don’t have to buy a second machine or hire one to complete the job. Fein currently offers a large range of Magdrills from 30-80mm capacity, the new cordless Magdrill starting at 35mm.
When it comes to depth of cut, most machines will be able to handle a cutter with a depth of 25mm. For most applications this will suffice but if you have an application which requires either the cutting of thicker material, or the drilling of box sections, or step drilling, it is worth looking for a drill with as large a stroke range as possible. Ranges can vary from 65mm to 315mm so it worth taking this into consideration.
What is the machine going to be used for? Again this may sound like an obvious question. You want to drill a hole into a piece of steel. You have chosen your drill based on the size of hole and material thickness, but there may be some other criteria’s to look at. Most Magdrills are fixed speed; they are designed to drill a hole into steel. This fundamentally keeps the cost of the machine low, and is how many Magdrill manufacturers make machines. Fein invests far more into its mag drills allowing the motor to deliver variable speed and is available in all Fein Magdrills (except the KBB range). This variable speed, and in addition reverse functions are important if you have varying diameter holes to drill or are looking for a Magdrill which can Tap, Ream or Countersink.
Nearly all Magdrills will accept cutters with a Weldon type fitting. These are usually fixed in place with 2 x grub screws located on the tool holder. The Weldon fitting has been used for many years and it has become an industry standard for both cutters and drills. It’s a great system, however, the difficulty can be when trying to change a cutter with the machine attached to the work piece. Locating the grub screws can be a problem and there is always the moment when you just can’t find your Allen key! Thankfully there are machines available with Weldon quick change chucks which eliminate any of these issues.
As mentioned earlier you may have an application which is not as straight forward as drilling a hole, like tapping. I would advise purchasing a drill with variable speed a reverse function and a good stroke range, also ensure that you can purchase the correct attachments. Auto Reverse Tapping Gearboxes are available on Weldon fittings which would allow your machine to tap without a reverse feature but these can be expensive so look for a drill with a tapping chuck in its accessory range like Fein and other premium manufacturers.
The correct cutter selection can make the difference between hours of frustration and expense, or getting a job done well. High Speed Steel, Tungsten Carbide, Titanium coated and High cobalt are some of the different cutter types available, and will all perform differently on different materials. It is worth seeking advice on which cutter would suit you application best and pairing it with the correct machine.
For example, if I was drilling into a piece of stainless steel, I would select a cutter such as the Tungsten carbide cutter due to its hard wearing characteristics. Ideally I would want to reduce the speed so I would select a variable speed machine, and then I have the issue of getting my magnet to adhere to the nonmagnetic stainless. Thankfully there are vacuum plates available which would allow this but I have now moved the machine away from the work piece and need the additional stroke range on my machine.
We have a function on our Fein website called ‘core drill finder’ which provides precisely this advice, https://fein.com/en_uk/drilling/metal-core-drilling/core-drill-finder-t642962/ . It provides information on the carbide (Ultra), coated HSS (Dura) and HSS (Nova) cutters, with various helpful information on the types of cutter sets available in the market.
Additional features and safety.
Once we have the correct drill and accessories for our application, it is worth taking a second to look over any additional features which may set one machine apart from another.
Capacity: As well as being used on site many of the larger capacity machines can replace the need for a conventional pillar type in the workshop. They make it easier to take the drill to the work piece rather than trying to move large pieces of steel up onto the drill bed. Larger machines are available with Morse taper fittings which allow for a wider range of accessories to be used.
Auto feed: When a large number of holes need to be drilled, Auto feed machines will allow for a greater accuracy when working out production times as each cut can be timed and repeated and will also give a longer service life of the cutter due to the constant feed pressure applied by the machine.
Ease of use: Ease of access to the controls can be something that is overlooked. The controls may be easy to access when the machine is operated in one direction but when turned around they may be impossible to reach. Try to find a machine which has controls that can be reached regardless of the orientation of the machine.
Safety features: Although using a Magdrill for larger diameter holes is much safer than using a conventional hand held drill they still have their dangers and should be set up and operated correctly. Always use the securing strap provided with the machines, the electro magnet will only operate if the power is on. Always fit the guard provided, this will help to contain the swarf created and also reduce the risk of coming into contact with the cutter.
Look for machines with tilt sensors and overload protection; these will shut the motor off if the machine moves for any reason during the cut, or if the cutter becomes jammed.
Slide adjusters: Over time the slide on your machine may wear slightly due to it being metal upon metal, a good quality machine should have adjustments on the slides so that you can remove any play and tighten your guide. Any play in the guide will lead to movement and chattering in the cutter which may break cutters and also lead to an oval hole being drilled.
As you can see there are a number of different decisions to be made before choosing the correct machine – capacity, depth of cut, applications, accessories, safety features, ease of use. It can be useful to ask for a demonstration of the product before purchasing either via the machine manufacturer or your local supplier to ensure that it is suited to your application.
There are many standard providers of mag drill in the market. Fein itself offers Economical models matching the same basic functionality as you might expect, whilst others are premium, offering variable speeds and the programs discussed (universal), or automated drill feeds (automatic). Fein was proud to launch two new classes of mag drill in late 2017, ‘Cordless’ and ‘Compact’. The brand new AKBU 35 (cordless) is supported with equally new high-power batteries and a new starter kit, helping end-users who lack mains power on-site or who need to work at heights. If working in confined spaces a specialist right angled Magdrill would be needed, with a minimum head clearance of 169mm. The new ‘compact’ KBC 35 would assist, small enough to help get into tight spots. Find out more about Fein’s mag drill range including these new machines: https://fein.com/en_uk/drilling/metal-core-drilling/