Router bit search - larger roundover

[David Epperson]

Hoping someone here might know. I've got a problem. I'm needing to put an approx 1-1/4" to 1-1/2" radius on the corners of some boxes. But I only have routers with 1/4" collets. I was wondering if anyone made bits that could do this in 2 passes - 45° from each direction - so the bit could stay small enough in diameter for a 1/4" shank.
Eventually I'll get a larger router, but I'd rather this project didn't drag on that long.

[glenn bradley]

A radius that size on 1/4" shaft sounds like a recipe for disaster. I would either go ahead and buy the router now and comfort myself with the fact that it costs a lot less than a finger or an eye ;). Or I would use the bandsaw to get to rough profile and finish it up with a plane. I think we're talking cross-grain cuts(?). Maybe a belt/disc sander and sand them to a line(?). Sorry, I'm just trying to toss out some ideas that don't require the new router.

Rockler has a 1-1/4": http://www.rockler.com/product.cfm?page=2127

And a Whiteside #2016 has a 1-1/2" radius: http://www.holbren.com/roundover/

[David Epperson]

Rockler has a 1-1/4": http://www.rockler.com/product.cfm?page=2127
The largest radius that their 1/4" shank bits will cut is only 3/8"

[glenn bradley]

The largest radius that their 1/4" shank bits will cut is only 3/8"

Yeah, sorry about that David. I posted before I completely finished my thoughts :D.

[Jamie Buxton]

That's a very big radius. I doubt if you'll find it on a 1/4" shank.

You might consider doing it mostly with the tablesaw. Make multiple cuts that approximate the curve. Then use other tools to take the ridges off. The other tool could be a belt sander, if you have one. Or it could be a sanding block. Or it could be a handplane.

[David Epperson]

That's a very big radius. I doubt if you'll find it on a 1/4" shank.

Yes it would be a very large diameter bit - IF I wanted to try and cut the whole 90° corner in one pass - what I'm hoping some one makes a bit that only cuts 45° at a time. Meaning I run the part through one direction, cutting 1/2 of the corner, flip the part around and run it through again to cut the other half. The bit does not have to be full diameter that way.

Something like the difference between a horizontal raised panel bit and a vertical raised panel bit.

[Will Overton]

Whiteside, Freud and Eagle America all have 1/2" radius bits with 1/4" shanks. These are the major players in this game, so even if you find an off brand with a larger radius, I'd shy away from it. There must be a reason the major brands don't make them.

You may want to look for a table top bit. You may find a profile that will work.

[David Epperson]

You may want to look for a table top bit. You may find a profile that will work.
LOL. Well there is no way I'd ever consider free handing one of those monster bits. I've got Slotters and a Lock Miter that are larger than what I'm looking for would have to be, but I was looking to find out if one of the "major players" did indeed make such a bit and I just haven't found it among the (seems like) 68,000 different profiles.

[Vince Brytus]

A 1/4" shank is not strong enough to reliably hold on to a bit that large. I doubt if anybody makes one because of liability. If that thing snaps off at 15,000 rpm you don't want to be in the way.

[David Epperson]

A 1/4" shank is not strong enough to reliably hold on to a bit that large. I doubt if anybody makes one because of liability. If that thing snaps off at 15,000 rpm you don't want to be in the way.
How large? The way I have the bit I'm looking for pictured, it wouldn't be as big or as aggressive as the 2" diameter lock miter I'm running now...And it has a 1/4" shank also. If I was looking for one to cut the whole roundover in one pass, then, yeah, you'd have a point. But I specifically ruled that out.
Amana makes a replaceable bit set up that I could have the blades reshaped - Might go that route if I can't find a more readily available option.

[Jamie Buxton]

This is kinda-sorta what you're describing. http://www.eagleamerica.com/product/v162-2005/ea_-_edge_forming

But it only comes in half-inch shank.

[David Epperson]

This is kinda-sorta what you're describing. http://www.eagleamerica.com/product/v162-2005/ea_-_edge_forming

But it only comes in half-inch shank.
Yep. That's real close...just a bit larger than I need. Which was why I was hoping to find a smaller one in 1/4" shank.

[Neil Brooks]

Trying to be helpful here, but ... not sure if I'll succeed :o

I do a fair bit of hobbyist bicycle mechanics stuff. I have most of the tools, but ... there are a few pretty specialty items that don't make sense for me to own. It's usually stuff that will get used once every other year.

Is THIS the kind of situation where ... it might make sense to contact a local woodworking shop, and see if they could bang this out on their shaper ??

Would a shaper even be easily able to do what you're looking to do ?

Just ... falling back on my training: trying to look at the problem a different way :)

[David Epperson]

Trying to be helpful here, but ... not sure if I'll succeed :o

I do a fair bit of hobbyist bicycle mechanics stuff. I have most of the tools, but ... there are a few pretty specialty items that don't make sense for me to own. It's usually stuff that will get used once every other year.

Is THIS the kind of situation where ... it might make sense to contact a local woodworking shop, and see if they could bang this out on their shaper ??

Would a shaper even be easily able to do what you're looking to do ?

Just ... falling back on my training: trying to look at the problem a different way :)
LOL. Yeah Neil, that WOULD be the overall easiest way to solve this. But it sort of defeats the purpose of the whole DIY woodworking endeavor. Solving the problem is half the "fun".

[Richard Wolf]

Maybe this will work;

http://www.toolstoday.com/p-4968-convex-edging-router-bits-bullnose-half-radius.aspx
Richard

[David Epperson]

Maybe this will work;

http://www.toolstoday.com/p-4968-convex-edging-router-bits-bullnose-half-radius.aspx
Richard
Well it does look like it's saying that that is a 90° arc, which would make a corner. I hadn't thought of presenting the work at a 45° angle, but it might be doable. Thanks. I'll keep that one in mind.

[David Epperson]

Well for any that might be interested. I ground a bit from a spade drill bit late last year. Finally tried it out today. My radius was a bit off, but I still have room to fine tune it some. It didn't do too badly at all considering that I more or less freehanded the radius profile on the bench grinder. I did have to do some lathe work to get the 5/16" shank down to 1/4" to fit the router collet. But I built a quick down and dirty fence from a piece of 2x4 construction lumber to enclose the bit, and help support it. It take 2 passes to complete the 90° roundover, but only requires a small amount of sanding to smooth the 2 passes together. That should improve after I tweek on it a bit.

[Peter Quinn]

Nobody makes a bit that large in a 1/4" shank, and I doubt anybody makes a bit half that large in a 1/4" shank either. Half of 1 1/2"R is still 3/4", and thats pushing it for a 1/4" shank. Why they make a lock miter on a 1/4" shank is beyond me, but that seems like too much material for the 1/4" shank if the thickness of material is above 1/2".

So the reason you haven't found one is because they wont make one because it is a very unsafe idea. But if you are into solutions, put away the router, hog out the waste on a table saw in a few passes with different blade angles, and grind your self a card scraper with the desired radius to fair the curves by hand.

[Karl Brogger]

I've never seen a bit that big in 1/2" shaft. That baby would be almost 4" in diameter.

[Chip Lindley]

...But it sort of defeats the purpose of the whole DIY woodworking endeavor. Solving the problem is half the "fun".

Hey David! Seems you solved your own problem. Just be aware those cheap carbon steel spade bits may not hold up well at high router speeds. The shank may not be a perfect fit for your 1/4" collet, making it slip and be jerked out of the router at high speed. Or, the collet may be scored and ruined, making it undependable to securely hold bits. HAVE FUN! But, proceed at your own risk!

[David Epperson]

Most 1/4" bit's I've seen are intended for the 24000rpm trim routers. As I am only using this bit on a larger and slower router (about 14000, I think) the diameter doesn't worry me much. But you're correct on getting the shank the right size and polished so as to hold without scoring the collet.
I made this one on a 15/16" spade bit and made sure that it was somewhat supported and guided at both ends.
I wouldn't dream of putting my 1/4" shank Lock Miter bit in a trim router.