[beren]

I was given a quite old craftsman 315.25070 router and need to use it for a project, so I need a bit for it. I'm hollowing out the center of some boards to hide the 2x4s between windows in my sun room. I've narrowed it down to a Bosch 85684mc and 85232mc, both 2-flute straight bits. One is 3/4x1" with a top bearing, the other is 3/4x3/4 and no bearing. Which would be the more useful (long term) to get? I need something from a local store since I'm doing this tomorrow, unfortunately. I was thinking the 1" with the bearing.

Thanks!

 

[fire65]

Both will be useful bits over time. If you do not have a router table the flush cut with bearing will be very useful (but probably more expensive) for many things especially pattern routing.

 

[Cherryville Chuck]

There are straight bits with no bearing, straight bits with a bearing at the bottom which are referred to as flush trim bits, and straight bits with a bearing at the top referred to as pattern bits. As Clay said, they all have a time and place. In this case a flush trim bit won't work for you but either of the other two will. The main difference is cost.

The two bits with bearings are for following a pattern or template. The flush trim bit will follow a pattern that is below your workpiece and the pattern bit will follow one that is on top.

 

[DaninVan]

Beren; not your question but are you talking about the rough framing that supports the headers over the windows? If there's one long header (over the top of a couple or more window openings) there may be only a pair of 2x4's between each window(?).
So, normally the finished window frame would come flush to the room-side face of whatever your wall material is, assuming 1/2" drywall here, a piece of drywall would cover the rough framing between the windows, and your window trim would go over that.
OK; my question is, why is the framing exposed? In fact why is it proud of the wall framing?
Is your window jamb set back from the finished surface of the wall? If that were the case, flushing up the window jamb with jamb extensions would be the easiest approach.

 

[mgmine]

If I understand your question you will not be able to use a bit with a bearing on it, because you will not be able to lower it enough to make the cut. It sounds like you are trying to make a wide dado in the wood.

 

[beren]

These are vinyl windows, I'm putting trim over the framing between the jambs. Between each window is 2x 2x4, some are countersunk, but some stick out so the trim needs to be cut so it fits over and is still flush with the windows. This is a sun room, with 3 walls of windows. After thinking about it, the 1" bit with the top bearing seems more useful, as the bearing could be ignored/removed when not needed. The main downside of this router is it's only 1/4" bits.

I didn't build the room, I just rebuilt it, so I have to deal with the idiosyncraties of the framing.

Basically yes, I'm making a 1/4" deep x 3 1/4" wide dado. I know the 1" bit is overkill, but it seems like the flexibility of having the bearing for the future plus the deeper possible cut is nice. The other bit is only 3/4" tall but it has the engraved depth markers. 85682MC vs 85232MC.

 

[DaninVan]

Ah, got it. A lot of trim molding comes with the back partially "relieved" for exactly that reason, irregularities in the various surfaces that the trim will cover.
I just used to use my circ saw, set very shallow, to carve out the unwanted material on the back. Just to be clear, I'm talking about running the saw perpendicular to the blade, ie sideways.

 

[Nickp]

Ah, got it. A lot of trim molding comes with the back partially "relieved" for exactly that reason, irregularities in the various surfaces that the trim will cover.
I just used to use my circ saw, set very shallow, to carve out the unwanted material on the back. Just to be clear, I'm talking about running the saw perpendicular to the blade, ie sideways.

Agreed...with makeshift fences and guides, I have used circ saw, table saw and radial arm.

Tricky first time, but like riding a motorcycle for the first time...within 5 mins you're yankin' cogs...:dance3:

 

[beren]

Yeah I gotta take out up to 1/4" 3"wide so gonna use the router for this but def have used various saws to do stuff like this. used a circle saw to make a 2x4 notch in a 4x4…