Review By Dean Bielanowski  Freud Website -

Freud Spiral Router Bits

By Dean Bielanowski

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When it comes to plunge cutting with the router, or even routing dadoes or mortises the straight flute cutting bit was the tool to use for the job. That was before the spiral router bit hit the market. Now we had a router bit that looked like a drill bit, and promised much faster plunge and slot cutting action with a cleaner edge finish too.

I admit that most of my dado work up to now has been done on the table saw with a dedicated dado set, and any mortises I needed were cut with my dedicated mortise machine, but of late I have started utilizing the router more for joinery work, as opposed to edge shaping, which is what I had predominantly used it for up until now. And as such, I needed a better way to cut mortises and stopped dadoes, so I decided to grab some spiral bits. Now, there are many brands on the market, but I headed straight for the top it seems and picked up a few Freud Spiral router bits based on feedback from other owners of these bits. I have a few other Freud bits already and they have proven to be quality router bits.

Freud Spiral Bits
When it comes to spiral bits, there is essentially one thing you need to know, apart from getting the right shank size for your router and the desired length and diameter of the actual cutting edges, and this is whether to buy a spiral "upcut" bit, or a spiral "downcut" bit. What's the difference? Well, the difference is in the efficiency that the dust and debris is moved by the bit. With spiral upcut bits, the debris is moved up toward the shank of the router bit more efficiently, making them suitable for deeper mortise or plunge cuts. These bits are best used for deeper plunge cuts, or if you are using the router to effectively "drill" holes rather than slots because they can remove debris from the bottom of the hole/slot where it may have no where else to go. One of the side effects of this bit design (because the spiral cutting edges are rotating and cutting up toward the bit shank) is the possibility of fraying or furring (perhaps even chipping) of the top edge of the slot or mortise, particularly if the router bit is of poor quality or becoming dull. However, if the top edge of the cut is going to be covered anyway, as in the case of the shoulder of a tenon covering the mortise edges, it may not be anything to be concerned about.

The up-cut bit seems more widely used than the down-cut bit however. The downcut bit is less efficient at clearing debris from the bottom of a plunge cut, however, it produces a smoother top edge with less chance of chipping, splintering or furring because the cutting edges and essentially rotation down toward the bottom of the cut, and the edges of the slot are supported by the material itself. I have found that even downcut spiral bits are more efficient at debris removal than standard straight-flute router bits for the cutting tasks. So before purchasing, consider which bit you need. Both bits will work great for cutting shallow slots or dadoes, but the upcut is more suited for deeper dadoes (these should be cut in multiple shallow passes however anyway) and the downcut will generally give cleaner topside edges.

Spiral Upcuts
I am looking at two spiral upcut bits from Freud (My only downcut bit has finally dulled to an unusable state). these bits are the 75-102 1/4" shank, 1/4" diameter up cutting bit and the 75-108 1/2" shank, 1/2" diameter up cutting bit. Both are made in the same way, with the same design and material. The only difference is shank size and diameter.

Both Freud bits appear to be made with high precision, and are finished well. Usually you can look at a bit and tell a good deal about its quality of manufacture just by its finish. A close examination of the cutting flutes showed sharp edges and no blemishes on either bit. The bits were a nice snug fit in both my routers (1/4" router and 1/2" router) and tightened up readily and easily.

Unlike regular router bits with carbide cutting tips, the Freud spiral bits are solid carbide from top to bottom. And not just any regular carbide either. These bits are made with a special Micro-grain carbide incorporating Titanium and Cobalt. Freud calls this TiCo High-Density carbide. I don't have any way of examining this carbide under a high powered microscope so I have to take their word on it. I am sure it is all above par and the performance of the bits would seem to suggest this is some pretty durable material in use. The bits are made in Italy.

The Bits in Use
I ran the bits through various tests in softwoods, hardwoods and sheet materials. Nothing terribly scientific. I simply cut some mortises in face grain and end grain in all materials, and then some direct plunge action cuts (drilling) using the bits. Varying depths of cuts and mortises across the grain and with the grain etc.

The first thing you notice with using a spiral bit is the ease with which it plunges down into material to make the initial plunge cut. With regular straight flute bits, this process if often less than smooth as debris can be trapped around the cutting area of the bit making plunging difficult and slow. The spiral bits clear the debris far more effectively and allow a smooth plunge action to be attained without hesitation or lifting the bit to clear the hole of any debris remaining under the bit. As you make a mortise trench, the value of the spiral bits also becomes apparent. If you have ever cut mortises or slots with standard straight flute bits, you might find you get to the end, then lift the router and see all the dust still jammed in the slot. With a spiral bit there can be debris still in the slot, there is no doubt about that, but the amount is much less and rarely will the slot ever be crammed full and packed tight with dust. This is perhaps even more noticeable when routing a mortise with  the bit set in a router in a router table since the table can close off any exit pathway for debris to take. A spiral bit will draw this debris downward to the router and hopefully be ejected from the mortise and from around the router with an extraction system of some kind. Needless to say, if your router has a good extraction system, you will end up with a cleaner mortise/dado/slot cut once all is said and done. In many cases with these spiral bits, there is little or no sign of dust in the mortise at all if you have a strong extraction system in place with your router. This makes cleanup almost a non-issue.

Also, consider heat on the bit. Excess debris around a router bit can create more heat, and the hotter the bit, the higher the potential for it to dull much quicker. I've "burnt" more than a couple el-cheapo straight cut bits routing dadoes and mortises in the past. Cheap router bits are not a wise investment, unless they are for a one-off task where quality of cut is not terribly important. Quality router bits are worth their weight in gold... well, carbide, anyway. Since spiral bits more effectively remove dust and debris, there is less chance for this heat buildup to occur.

I made many cuts in different types of materials and in both soft and hardwoods. The results were virtually the same across the board. Smooth edge, clean mortise and trench/dado cuts in virtually all materials. The only time I had furring of the edge was when cutting across the grain on pine, which has a tendency to fur up easily anyway. This was readily removed with sandpaper. The bottom of the cuts were all very smooth and more than suitable for visible shelve joints or similar joinery.

Overall I am very happy with the Freud Spiral Upcut bits. And although straight flute bits are quite a bit cheaper on initial purchase, I believe spiral bits offer more value for money over the life of the bit, and give better results to boot.

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As Reviewed Above

Other Common Freud Spiral Upcut bits (USA)
Freud Up-Spiral Router Bits Freud Up-Spiral Router Bits
Upward spiral is perfect for ejecting chips from mortises. Its also the ideal bit for pattern routing because the best face goes down while cutting, with templates attached to the top. 1/2" shank...

Freud Up-Spiral Router Bits

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Freud Spiral Router Bit Photos
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Freud 1/2" and 1/4" Spiral Upcut Bits

Each bit has two spiral cutting flutes

Each bit is precision machined and finely finished.

Two plunge mortise cuts in melamine. The edges are clean and sharp, even where the bit was plunged down into the material.

This mortise cut across the grain of some pine did produce some furring around the top edges using the upcut bit. But this is easily removed with sandpaper and you can see the top edges are still sharp and clean.

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