The RapidFeedTM bits are available in sets (6pc., 6" with extension pictured) or individually. Click image to enlarge

Bosch RapidFeed^TM Spade Bits

Boring wood is less boring

Text & Photos by Tom Hintz
(UPDATE: See Below)

Boring holes is a common woodworking task that can be frustrating when the bit being used does not perform well. When the hole is deep, or passes through the wood entirely, the task gets more difficult. Like many of you, I have tried spade bits from a number of manufacturers with very little difference in the results. They went dull quickly, caused chipping around the entrance hole and could tear large chunks of material from around the exit side. When Bosch announced the release of their new RapidFeed^TM spade bits, I had to give them a try.

Updated Design and Manufacturing

   The spade bit has been around for decades and the manufacturing process has changed very little along the way. Finally, the Bosch engineers went to work and came up with improvements that really make a difference.

   Bosch RapidFeed^TM bits look similar to most spade designs except for two noticeable improvements: the threaded tip and the high-quality manufacturing. There are other more subtle changes that are no less important to how these bits work.

More Pull, Less Push, Fast Cuts

The new threaded tip and wing cutter designs are highly effective. Click image to enlarge

   The threaded tip (patent-pending) literally pulls the bit into the wood, virtually eliminating the need for pressure applied by the operator. When many holes have to be drilled, this pulling action can substantially reduce fatigue. Bosch literature claims the threaded tip allows the Bosch RapidFeed^TM bits to drill wood up to three times faster than conventional designs. After using the Bosch RapidFeed^TM bits in my shop that claim appears accurate, if not understated.

   The angle of the cutting edges has been increased to help them keep up with the faster feed rate. Even the spurs have been redesigned so they score the perimeter of the hole as they enter the wood to reduce chipping. The Bosch RapidFeed^TM bits also slice a cleaner path ahead of the cutting edges to reduce tear out as the bit exits the other side of the wood.

No Slip Chucking

The 6" RapidFeedTM bits feature the click lock grind. Long bits and extensions have a 1/4" hex drive end. Click image to enlarge

   To eliminate slipping or spinning in the chuck under load, the ends of the Bosch RapidFeed^TM bits have also been refined. The 6"-long bits feature the popular ¼"-hex click-lock profile so they can be quickly locked into or removed from most common retainers. The drive end of the 16"-long bits and the extensions are ground to a ¼" hex shape that allows common chucks to get a firm grip on them.

Extension Shafts

   To increase reach, extension shafts are available in 6" and 12" lengths. Both extension sizes feature heavy-walled sockets with two setscrews that lock the bits securely in place.

   The shafts of the extensions are very stiff and resist torquing and flexing very well.

   Note: While the Bosch RapidFeed^TM bits themselves can be used in a drill press, the extensions cannot.

In The Shop

   I have used the Bosch RapidFeed^TM bits in my cordless driver, drill press and in the lathe. In all cases they performed exceptionally well, easily exceeding the performance of any other spade bits I have tried in terms of cutting speed and the quality of the hole itself.

   The Bosch RapidFeed^TM bits tip is so effective at pulling the bit through the wood I had to change to the power setting on my cordless drill. The Bosch RapidFeed^TM bits remove wood very quickly and even on the slower power setting, holes are completed far faster than with common spade bits operated at the drill's faster setting. To be fair, I tried the standard spade bits with the drill in the power mode and only succeeded in drilling slower with no improvement in their performance.

On the left is a standard, but not cheap spade bit. On the right is a RapidFeedTM bit, both 1"-diameter. The wood is a common pine 2X4, the results, not so plain! Click image to enlarge

   I also discovered that as the Bosch RapidFeed^TM bits threaded tip exits the wood, the auto-feeding action stops. This allows the operator to work the bit through the back surface slower, taking advantage of the spurs slicing action to help produce a much cleaner exit hole.

   When using Bosch RapidFeed^TM bits in a drill press, I found it best to place a thick backer board below the work piece and clamp both in place. Set the depth stop so the main cutter edges enter the backer 1/8" to ¼" deep. The Bosch RapidFeed^TM bits cut very quickly even with the press set to its slowest speed. If the work piece is held tightly to the backer, as you should with any bit, and the depth stop is set correctly, tear out at the back of the work piece is virtually eliminated.

   On the lathe, the Bosch RapidFeed^TM bits are remarkable. One of the reasons I was looking for a better bit was for drilling peppermills, particularly those with bodies over 10" in length. The standard spade bits I had been using were heating up and wandering badly regardless of the technique used. The rpm setting of the lathe, or how often they were retracted to clear the chips made little if any difference. The standard spade bits also required considerable feed pressure to keep them cutting.

Tracking of the RapidFeedTM bits is very good. I bored the 20"-long body of this cherry peppermill with a 16" bit, half from either end. The holes met almost perfectly in the middle. Click image to enlarge

   Installing Bosch RapidFeed^TM bits drastically improved all of the above problems. They tracked much straighter and cut cleaner. With the self-feed action of the Bosch RapidFeed^TM bits, I found myself cranking the feed handle faster just to keep up.

   Tracking with the Bosch RapidFeed^TM bits through the irregular density of a spinning piece of wood is not perfect, but it is noticeably better than with any other bit I have tried. Tracking did not seem to suffer even when I added the 12" extension.

   One of the first projects the Bosch RapidFeed^TM bits were used on was drilling a 1"-diameter hole through a 20"-long cherry peppermill body. I bored the hole equally from either end, as I would with the standard bits, but the results were far better. The holes met in the middle much closer and got there faster than I have ever experienced. The sides of the hole were also cleaner and required considerably less sanding than I was accustomed to.

Conclusions

   The engineering team at Bosch Tools has once again taken a long accepted tool and improved its performance substantially. For the woodworker, boring holes in wood is easier, more accurate and produces cleaner holes thanks to the improvements incorporated into the Bosch RapidFeed^TM bits .

UPDATE:

Drilling peppermill bodies used to be a tough job, until I started using the RapidFeedTM. Click image to enlarge

   Drilling the 1"-diameter hole through the center of tall peppermill bodies has been a problem as long as we have been making peppermills. Recently, I tried a 12"-long, 1"-diameter Bosch RapidFeed^TM bits to drill an 18"-long, hard maple body. The results, as shown in the photo, shocked me.

   I drilled this body from both ends, as I always do with peppermill bodies longer than 10" or so. The body was chucked and supported with my home-made steady rest. I started the hole at each end by using a 1"-diameter Forstner bit, drilling in about 2" before changing to the Bosch RapidFeed^TM bits to drill the rest of the way to the center of the body.    

As you can see in the photo, the slug that fell out when I removed the body shows the Bosch RapidFeed^TM bits went right down the center of the body, something I have never had happen before, especially at these depths. The slug is the same diameter as the bit and a look down the hole shows there are no ridges in the hole where the bit met. A little sanding is all that was needed to clean the hole for use.

   Guess what bit I will be using from now on to drill peppermill bodies!

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