I own a Bosch 1617 EVSPK, so why would I need this?

[Herb G]

My router comes with a 1/4" & a 1/2" collet, so why would I need this?

Linky

What would it be used for, since the other collets would fit the same sized bits?

[jteneyck]

You need that if you want to use 3/8" diameter shank router bits. Your other option is to use a 1/2" to 3/8" bushing in your 1/2" collet, but that's not as good as the 3/8" collet.

John

[JGrout]

I have 1/4, 3/8, 1/2, 8mm and 10mm collets for that router.

I use them all

[Herb G]

jteneyck said:

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You need that if you want to use 3/8" diameter shank router bits. Your other option is to use a 1/2" to 3/8" bushing in your 1/2" collet, but that's not as good as the 3/8" collet.

John

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Cool. Thanks John. I'd give you a thumbs up, but this forum doesn't have one. So a will have to do.

Oh yeah, would I run into a lot of 3/8" stuff in normal woodworking? Or is that some kind of specialized stuff I have no idea about?

[Richard D.]

You absolutely do not need that.

[Arlin Eastman]

Herb

I find that 90% or better router bits that are needed are either 1/4" or 1/2". Some are 8mm or 3/8" but it is highly likely that they are also sold in the first two sizes.

Also there are neat bits for making inlay which are in both 1/4 and 1/2 and the cutting ends are in 1/8" to make the inlay or even 1/16".

What are you doing that needs a 3/8" bit?

Arlin

[Jeremy s]

Amerock hinge bits

[Steve N]

Most 3/8" shanks are going to be for end mills which are growing in popularity as a solid carbide cutter, often much cheaper than a 1/2" shank cutter would cost, and the 3/8" is still a lot more robust than a 1/4" cutter. They also come in HSS cutters and are at throw away pricing compared to your up or down spiral solid carbide cutters. Some of these have tricky cutting geometry, so you need to know which to buy for what, and sometimes the information on them assumes you know this already. Some of the CNC guys may be able to illuminate that journey.

Here is a Whiteside product catalog Note at the top where they have up and down bits, and compression bits you will have 3/8" choices. When you go further down to the edge bits they start to become pretty much just 1/4" and 1/2".

[fredhargis]

JGrout said:

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I have 1/4, 3/8, 1/2, 8mm and 10mm collets for that router.

I use them all

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Same here, and I wish there were more 3/8" shank bits available, all the ones I have are Whiteside. As Steve N indicated, the extra meat in the shank is a welcome feature. Not sure how I came up with the various metric bits, but I alos have a handful of them. The metric don't used all that often, but the 3/8" one sees more use than you wluld think. Someone else mentioned it above.....those adapter rings just aren't all that good; I refuse to use them.

[Latech15]

I just bought a 3/8" adapter so that I could use one very particular 20mm bit for making a MFT style workbench top. Haven't needed one up until this point though.