Kosher router bit usage

[Victor Robinson]

This is probably a dumb question, but something I've been wondering.

Is it ok to remove bearing of a flush-trim bit to use the bit as a regular one?

I have a 1/2" up/down spiral flushtrim but need a bare 1/2" of the same type. Can I remove the end double bearing of the flushtrim and use it as such? Is purchasing the same spiral without bearings essentially "doubling up" on a router bit?

[Lee Schierer]

I'm not familiar with Kosher bits; however, if you are going to try to cut anything with the bottom of the bit, the answer would be no. There is usually a shoulder or ridge on the bottom of a flush trim bit to provide clearance for the bearing to be able to rotate that will not cut wood and will leave a serious burn mark. You could also possibly damage the bit.

[Greg Hines, MD]

You would be better off get a dedicated 1/2" spiral bit to what you are suggesting. As Lee says, there would be a shoulder that would make it impossible to plunge with it. And if you aren't going to be doing that, why would you need to remove the bearing to being with? If you are looking to convert it to a pattern makers bit, with just a bearing to the top side, I cannot imagine your tolerances would not allow the lower, distal, bearing to ride.

Doc

[Prashun Patel]

The bottoms of a normal spiral bit are sharpened to allow them to make plunge cuts. This may not be the case for a bottom bearing bit.

[Victor Robinson]

Thanks guys, I figured this but wanted to double-check I didn't already have what I needed before buying the plain 1/2". Thanks much.

[Prashun Patel]

FWIW, I have a few of the MLCS spiral bits. They are cheaper than the 'better' brands.

Also, if you are only using these infrequently, or for one project, they make them in HSS as well. They cut fine, just don't last forever. I bought a couple 'disposable' ones like this, and honestly, they still work fine 2 years out (but I'm a hobbyist).

[Victor Robinson]

FWIW, I have a few of the MLCS spiral bits. They are cheaper than the 'better' brands.

Also, if you are only using these infrequently, or for one project, they make them in HSS as well. They cut fine, just don't last forever. I bought a couple 'disposable' ones like this, and honestly, they still work fine 2 years out (but I'm a hobbyist).

That's definitely an option I'm always aware of, but in this case I'll be going Whiteside as it's more than a one-off. I was just going through my bit drawer and realized that I had the flush trim version of what I was going to buy. The compression spirals are spendy, but they're sweet when they are the right bit for the job.

Since you mentioned MLCS, worth noting that 1/2" compression is $45 there, vs. $60ish for the Whiteside (depending on retailer).

[glenn bradley]

I see no issue although the stem for the bearings may be just as much in the way as the bearings themselves . . . maybe not. I have a large collection of bearings and collars and use bits with a variety of bearings (including none at all) to get the job done. I don't find many uses for a bearing guided bit sans-bearing (again, due to the stem) but, have done it. I would be sure to remove the screw and washer(s) along with the bearings and be aware of the stem in relation to your cutting path.