Spiral bits, upcut, downcut, combo

[LinuxRandal]

What are your most used size of each applicable?

Been watching the Bosch bits at Lowe's due to the bargain alert (not here ), but they never had any in stock. They finally had one, but I am wondering about buying a set, or best option for this (rather spend with Holbren if possible).

Thanks all

[RodKirby]

Mine are all upcut (=downcut in the table). I have a "set" - all solid carbide.

3/16" - not used yet
1/4" - used often for cutting slots
5/16" & 1/2" - used occasionally for squaring edges. (Workpiece behind the bit - fed left to right on the table).

1" (carbide tipped) used all the time for rabbets.

I love the way they cut - slice instead of scrape

[gsmittle]

I have three, all upcut. 1/8" and 1/4" Whiteside solid carbides that cut like a dream, and a 3/8" HHS that I wouldn't wish on my worst enemy. I learned in a hurry that trying to save a buck on router bits is false economy of the worst sort.

g.

[Stytooner]

I have a 1/4" spiral upcut trim bit with two bearing on bottom. I have been using it about 4 to 5 years now. I use it for flush trimming aluminum and lexan a couple days a week every week. Still shows no signs of wear. It is solid carbide. I thought the original price of $44 was high at the time, but not so. Well worth the money. I think I got it from MLCS.
They really do a fine job and last forever with normal usage. Only breakage would be it's downfall.
I wore out a Dewalt trim router using it and now working on doing the same with a Ridgid trimmer.

[LCHIEN]

I find I use the 1/4" and the 3/4" mostly.
I use the upcut variety... because I mostly do grooving and material removal is useful. I think the downcut is mostly useful for preserving a clean edge at the top of your work.

[Bruce Cohen]

Downcut Spirals leave you with a clean face, but the chips hasve to be constantly removed from the mortise, and if its a thru cut, you'll have blow out on the back, unless you use a backer board.

Upcuts will give you a slightly rough entry but will clear the chips much faster and easier, and leave a clean edge in a thru cut. No backer is needed.

Compression (very pricy) work both ways, I've never used them, but they're suppose to fill the bill of not having to buy both types if your work requires both features.

Of course, if the bit is used in a table then reverse the up and down cuts. The compression doesn't matter.

Bruce

[Holbren]

Most popular for me is 1/4" upcut 1/4" shank (cost is much less), 3/8" upcut for mortises I assume, 1/4" upcut (1/2" shank stell body) and 1/2" upcut.

Sell a downcut now and again too. 1/8" downcut is popular for inlays.

[LCHIEN]

As much as I preach gettting 1/2" shanks, 1/2" shanks for 1/4" straight bits is a waste of time. It'll break at the bending point or the thin point, which for a 1/4" Straight or spiral bit, would be at the reduction of the shank to 1/4" or in the middle of the cutting area where its thin. due to the flutes.
The only reason to get 1/2" shank, 1/4" staright bits is because you lost the 1/4" collet from disuse or you're too lazy to change it! Liek Brian H said, 1/2" shank will cost a lot more to make, esp in the solid carbide spiral bits.

[JimD]

I have a 1/4 upcut with 1/4 shank, solid carbide that is getting a little dull - it's been used a lot. I also have a 1/2 inch 1/2 shank HSS that has been used a little (also upcut). For bigger mortises, I tend to use my dedicated mortiser. I would like to have a 3/8 and have been thinking of getting a set from MLCS. I think they have a 1/4, 3/8, 1/2 inch set for $50 (your choice of upcut or downcut). It saves you about the price of the 1/4 inch bit. Maybe Holbren has something like this.

Jim

[Holbren]

Funny thing is Whiteside didn't even make a 1/2" shank 1/4" spiral bit because it just didn't make sense in their mind for the reasons Loring pointed out. When they finally released it last year, they did something creative. They braised 1/4" carbide bar stock to a 1/2" steel body so only the cutter is solid carbide. By doing that they didn't have to start with 1/2" carbide bar stock and machine down the cutter and the cost is greatly reduced.

Here is how the prices stack up.

1/4" cutter 1/4" shank $15.60
1/4" cutter 1/2" steel shank $22.80
1/2" solid carbide (1/4" would be same price) $27.60

Theoretically the 1/4" cutter 1/2" solid carbide bit should cost more than teh 1/2" cutter version because machining time would be longer.