Router Bits - Frequently Asked Questions

Here are some tips for beginners and frequently asked questions about router bits. If you have a question that isn’t answered in this FAQ please contact us.

What is the difference between Amana router bits and other, less expensive store-brand bits?

Answer: Actually there are a number of differences that affect the quality of the cut and the longevity of the bit. One of the main differences is the materials used for manufacturing. Amana uses the finest steel for the body of the bits and fine grain carbide for the cutting surfaces. The finer and harder the carbide, the longer you have before it wears. Carbide on the Amana bits is thick allowing it to be sharpened many times. Inexpensive bits sometimes have inferior brazing which can cause the carbide to break loose during use.

 Unlike a saw blade which is secured to an arbor with a nut, a router bit is simply squeezed by the router collet. This method of securing the bit is effective if the shank of the bit is properly sized. However, sometimes the shank size of inexpensive bits can be as much as .008” under the collet size. This can cause the bit to slip, or creep out of the collet during use.

 Most of the quality features in Amana bits, such as shank size, carbide grain size, and brazing, cannot be seen without special tools and magnification. However, the differences can easily be seen in the quality of the cut and the life of the tool.

While cutting a groove with a straight bit, the bit crept a little out of the collet. As a result, the groove was too deep at one end.

Answer: The bit shank may be undersized; if the shank is too small, the router collet cannot grip it firmly. Amana’s bits are carefully ground and polished to no less than .001” of the collet size to ensure a secure fit in the router collet.

Also, the router collet may be worn. In fact, most collets show signs of wear long before the router motor is worn out. I suggest that you replace the collet and check each bit with a dial caliper. Bit slippage can not only spoil your work, it can be a safety hazard.

I’m new to woodworking and routers. Can you recommend a few bits for someone just starting out?

Answer: Profile bits are the most common and can be used to quickly and easily dress up the edge of a table top or drawer front. There are several popular styles such as the ogee bits, round over bits, and the simple but effective chamfer bits.

Straight bits are useful for cutting a lot of different woodworking joints from mortises and tenons to grooves and dadoes. It is a good idea to have on hand straight bits in several different diameters.

 These bits are good for starters. As your woodworking skills increase you’ll have a better idea of the router bits you’ll need to add.

How do I choose between a horizontal raised panel bit and a vertical raised panel bit?

Answer: Horizontal raised panel bits allow the panel to lie flat on the router table which provides lots of support for the panel. Also, most woodworkers find it less awkward to feed the panel when it is lying flat. However, because of the large diameter, horizontal raised panel bits require a large router (three HP or more).

In contrast, the relatively small diameter of a vertical raised panel bit allows it to be used in smaller, less powerful, routers. And vertical bits can be used to shape a panel which is curved across the face.

What is the advantage of a spiral bit over a standard straight bit?

Answer: Spiral bits produce an incredibly smooth surface, especially on figured wood and tough end-grain. This is because spiral bits cut with a shearing action. And, unlike standard straight bits, the cutting edges are always in contact with the stock. This eliminates the possibility of a “washboard” surface on the stock. The bottom line is that a spiral bit will virtually eliminate the need for sanding.

My router accepts only 1/4" shank bits. Yet many of the bits that I would like to use have a 1/2" shank. Why are there not more 1/4" shank bits available?

Answer: Many years ago, almost all routers had a 1/4" collet. Most of the router bits available during that time were small, too. Today, there are more router bit profiles available than ever before; woodworkers today can shape many profiles, such as a raised door panel, that once required an expensive industrial shaper. However many profiles are much larger than what can safely spin on a 1/4" shank.

When selecting router bits, if the profile is available in both 1/4" and 1/2" shanks, I almost always opt for the 1/2" shank. (Sometimes I use 1/4” straight bits in my laminate trimmer to cut shallow mortises for hinges and other hardware). The cross-section of a 1/2" shank is nearly 1-1/2 times that of a 1/4" shank. The bottom line is that 1/2" shank bits are considerably stronger and provide a safer, smoother cut. If you’re still using your 1970’s router with the 1/4" collet I suggest that you upgrade.

I flush trim a lot of curved parts in my work. I’d like to have a smoother finish but the “uphill” side is always rough. Any solutions?

Answer: One fundamental rule in woodworking is to cut with the grain; cutting against the grain can create a rough surface. The solution when flush trimming curved parts is to use the Amana Tool Down-Shear Multi Trimmer. Unlike ordinary flush trim bits, the Down-Shear Multi Trimmer has two guide bearings, one at the end and a second on the bit shank. This allows the template to be used on either side of the work and always cut “downhill”.

I’ve noticed that there are a number of insert router bits available today. Many are popular profiles that I use often. What are the advantages over standard brazed bits?

Answer: Actually, insert router bits have several advantages. Because the carbide is not subjected to the intense heat of brazing, harder longer wearing carbide is used. And some insert bits, such as straights, have more than one cutting edge. As the insert knives wear, they can be rotated to expose a fresh cutting edge.
Unlike brazed bits, flush trim insert bits always remain tangent to the guide bearing for a perfectly flush cut.