Bits&Bits 1/8″ Long Reach Spiral Compression Bit

$54.99

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Key Features

1/8″ cutting diameter with 1″ cutting length
Compression cut for clean top and bottom edges
1/4″ shank for compatible router collets
Solid carbide with AstraHP coating
Made in the USA by Bits&Bits

Description

Solid Carbide Compression Router Bit 2 flute with a cutting tip diameter of 1/8 and a 1″ cut length. These tools are coated with a proprietary high performance *Astra coating* that allows higher speed & feed rates as well as extended tool life & increased lubricity in abrasive material. Our compression bits are designed for CNC applications requiring high feed rates and compression cuts. They work well for double-sided melamine or laminated material.

What is a Compression Bit?

A Compression bit is a spiral bit that combines up-cut and down-cut action into one bit. The cutting tip pulls the fibers and chips up towards the center of the workpiece. The rest of the bit is cutting and pushing wood fibers down, also towards the center of the workpiece. This up cut down cut action is what leaves a sharp, clean edge on both edges of your workpiece. The up-cut flutes on a compression spiral bit are typically equal to the diameter of the bit, for example, a 1/2″ diameter has an up-cut flute of 1/2″. The transition point is referred to as the ‘Spiral Change‘. We also offer several sizes of compression bit with a shorter up-cut flute length which is referred to as a short flute compression (also called a mortise style compression bit). The slow-mo video clip below was shot by none other than Jonathan Katz-Moses and shows the cutting action of the compression bit. You can clearly see the difference between the up and down cut portions of the bit.

How do I use the Compression bit correctly?

In order to properly use a compression bit to get its full benefit, your initial cut needs to be slightly deeper than the upcut flute length, which as mentioned above is usually equal to the diameter of the bit. When used correctly, you shouldn’t see any tear-out or chip-out on the edges. In the video above, the bit on the left is seen cutting not deep enough to pass the up-cut flutes. The bit on the right is set at the correct depth.

Can you use a Compression Bit in a router?

Yes, all of our compression and spiral bits can be used in a CNC, handheld router, or router table.

Specifications

Product specifications
Bit Type	Spiral
Cut Direction	Compression
Shank Diameter	1/4″
Cutting Diameter	1/8″
Material	Solid Carbide
Coating	AstraHP
Cutting Length	1″
Overall Length	2-1/2″
Flute Count	2
Spiral Change	0.12″

Shipping & Returns

Domestic Shipping

Standard (3-5 days): $6.95

Priority (2 days): $9.95

Free Shipping on orders over $75

Worldwide Shipping

Canada: $18+

EU coming soon.

Return Policy

Returns are accepted within 90 days of the purchase date for items in new or gently used condition with its original packaging.

Frequently Asked Questions

What size collet do I need for these bits?

A 1/4″ collet. Every bit in this range has a 1/4″ shank, including the 1/8″ and 5mm cutting-diameter bits, so it fits a router with a 1/4″ collet. Cutting diameter is a separate spec: most of the bits cut 1/4″, the long-reach compression bit cuts 1/8″, and the 5mm up-cut bit cuts 5mm.

Can I use these bits in a handheld router or a router table?

It depends on the bit. Bits&Bits states that its spiral and compression bits can be used in a CNC, a handheld router or a router table, and that the compression bits are designed for CNC work at high feed rates. The three 1/4″ flush-trim bits (up-cut, down-cut and compression) are the exception: Bits&Bits specifies them for light, controlled trimming in a trim or compact router after rough-cutting close to the finished shape, and does not recommend them for heavy stock removal, larger high-torque routers or router-table use.

When should I use an up-cut, down-cut or compression bit?

It depends on which face of the cut needs to stay clean and where you want the chips to go.

Up-cut bits move chips up and out of the cut; the low-helix version uses a shallow spiral to help reduce upward pull on the workpiece, and the single-flute O-flute version is made for plastics, acrylic, aluminum, foam and solid-surface material where chip clearance matters.
Down-cut bits push chips into the cut and help leave a clean upper edge, so they suit grooves, pockets and profile cuts in plywood or laminated material where the top surface matters; plan chip removal when routing deep pockets.
Compression bits combine an up-cut tip with down-cut upper flutes to help control tear-out on both faces of wood, plywood and double-sided laminated panels, provided the cut runs deeper than the spiral change.

What materials are these bits rated for?

It varies by bit, so check the workpiece materials listed on each product. The spiral, compression and flush-trim bits are rated for wood, plywood and laminated material (each listing shows which), and the compression bits are the ones also called out for double-sided laminated panels and melamine. The 1/4″ low-helix up-cut bit is rated for plastics, acrylic, foam, wood and plywood, and the O-flute up-cut bit is the only one rated for aluminum and solid surface, alongside plastics, acrylic and foam. Set feeds and speeds for the specific material; a setting for acrylic is not a universal setting for aluminum or other materials.

How deep should the first pass be with a compression bit?

Slightly deeper than the bit’s up-cut section, so the down-cut flutes are cutting the top face of the workpiece. Bits&Bits’ rule of thumb is that the up-cut section is typically equal to the bit’s cutting diameter, but go by the figure on the product page where one is given. On the 1/4″ spiral compression bit (425-CM250) the spiral change is at 0.22″; on the short-flute compression bit (425-CM250SF) the up-cut section is only 0.12″, which lets the down-cut flutes engage closer to the bottom of the cut for mortise-style cuts and thinner double-sided laminated material. At the correct depth you should not see tear-out or chip-out on either edge; if you do, the first pass is not getting past the up-cut flutes.

What is the AstraHP coating on these bits?

AstraHP is Bits&Bits’ proprietary high-performance coating, and every bit in this range has it over a solid-carbide body. Bits&Bits says the coating allows higher speed and feed rates, extends tool life, and increases lubricity in abrasive material.

Who makes these router bits?

Bits&Bits does. Every router bit we carry is a Bits&Bits solid-carbide bit, a third-party brand we stock alongside our own accessories; they are not made by ToolCurve. Because they are not ToolCurve-made, they do not count toward the $75 free-shipping threshold.