HELP! Bullnose bit has no bearing!
JandMayra
| Posted in Power Tools and Machinery on
Hello.
I am attempting to construct several desktops with irregular shapes from solid stock red maple. The stock is edge glued, rough cut to shape with a jig saw, then trimmed using a template and a 1/2 inch pattern cutting router bit. The problem arises when I apply the edge treatment. I would like to use a one inch diameter bull nose to round the edge, however, my bull nose bit does not have a roller bearing against which I can set the template. Also, since the overall shape contains concave and convex sections, a (straight) fence is of little use. Is there any way that I can generate my desired shape repeatedly, or am I simply going to have to freehand it and hope for the best?
Thanks for your consideration.
Replies
You could make a smaller template and use a template bushing in the router.
Freehand will not work.
A new bit would probably be cheaper than suggestion #1 ans certainly cheaper than even the first instance of doing it freehand.
Dave
Hello Patto.Thank you for replying to my request for help. I have a set of collars for the router in question. However, the one that fits would force me to extend the bit out of the bottom of the router so far that little shaft would be left in the collet. This seemed dangerous especially since there will be a fair amount of force exerted on this bit as it cuts.I have also attempted to locate another bull nose bit with a bearing, but I cannot find one in the one inch range. Smaller radii bull nose bits with bearings yes, but not in the one inch size.Thank you for your thoughts.J.
J,Is that 1" radius or 1" diameter? If you are putting a half round on the edge of 1" stock you need a 1/2" radius. These are available with bearings. The Freud version is the 82-514.
Charles M
Freud America, Inc.
Hello CharlesM.The edge is one inch thick, so I will need a 1/2 inch radius. I checked several catalogs while planning this project, but must have missed this. Some manufacturers list dimensions by radius, others by diameter...Thanks for your reply.J.
Amana makes a corner rounding bit, #57190 with a radius bearing for this appplication. If memory serves it's about $80. Bit number is 57190 in the Amana catalogue under solid surface bits, corner rounding. I believe you could just purchase the bearing if you wanted to. If you do go this route use the same router bit for top and bottom, changing the bearing and not the bit. Bits may not have the exact same radius even if they are from the same company. I've used this a number of times to make bullnose window stools, nosings, etc.
Justin
Justinh ...This is the bit you refer to ...right:?http://www.amanatool.com/bits-fv/57190.htmlThis bit has a tapered delrin bearing you replace the metal bearing with and it theoretically gives a seamless bullnose..You make one pass with the 1/4 round and metal bearing then the other side is done with the delrin...10saw
Hello justinh.Thanks for replying to my post. This is an interesting solution. A manufacturer who finally realized that a straight bearing will not work on the second pass.
You can buy bearings and collars to go on the shank of the bit, and reference a template from there.
Woodcraft and others sell kits of bearings, bearings with sleeves, associated collars, screws, wrenches and lubricant. You just slip the bearing over the shank on your bit and lock it in place with a stop collar.
Shop around. Several vendors have quality kits, but the price and contents varies quite a bit. I got mine a woodworking store a few years ago. The owner was buying the components in bulk and putting the kits together in house. It cost me about $70, but had a dozen of the 3/8 and 1/2 od bearings that are on most of the bits, a dozen long and a dozen short screws, three 1/4-inch collars, three 1/2-inch collars, 1/4-inch id bearings and bearings with sleeves from 1/2 to 1-1/4-inch diameter, and 1/2-inch id bearings and sleeves from 1 to 2-1/2 inch od, an assortment of hex keys, and a tube of lubricant, all in a fitted wood case. I couldn't have bought all the bearings for that.
Hear are a couple of links to give you an idea of what I'm talking about.
http://www.woodcraft.com/family.aspx?FamilyID=5145
http://www.pricecutter.com/product.asp_Q_pn_E_199-9641
You can usually find some of the smaller bearings on ebay by the dozen, and the larger ones show up from time to time. There are usually some stop collars on ebay too.
Hello Jigs-n-fixtures.Let me see if I understand what you are saying. As I assemble the router, I would slide a bearing over the 1/2 inch shaft of the bit, then insert the shaft into the collet, right? Depending on the thickness of the bearing there should be enough shaft left for the collet to safely mount, right?At first glance, I am concerned that the diameter of the bearing will be too large to allow the deepest portion of the cut (the center portion of the radius closest to the shaft) to be made. I now see, though, that it does not matter since I can resize my template to accommodate this. Also, since the bull nose has "wings" that extend out at the top and bottom of the bit, I guess that I will have to modify my template with rabbets (as deep as the "wings") around the edges. One thing that puzzles me...router bits are sold with either 8mm, 1/4, or 1/2 inch shafts. Why do they include bearings with inside diameters of 3/16, 3/8, etc. in these kits?Thanks for your reply.
Edited 1/16/2007 9:11 am ET by JandMayra
You install the bearing and then a lock collar, to make the conversion to a pattern bit. If you take the collet out of the router, and slide the bit into it until it reaches the end of the collet, there should be enough of the shank outside of the collet to attach the bearing and lock collar.
The bearings with the 3/16 and 5/16 and 3/8-inch i.d. are replacement bearings, for bits with the bearing on the end when they come from the factory. Also, if you have a bit with a 1/2-in o.d. bearing on say a 3/8-inch radius roundover, you can install a 3/8-inch o.d. bearing and it becomes a corner beading bit. Also by going to a larger bit you can control the profile that is cut to something less than the full profile. Look as an ogee bit, and think about what it is going to look like if the inside 1/4-inch isn't part of the profile. The ability to vary the portion of a profile that is cut, gives you a great deal of flexibility in your work.
Also, if you use a 1-1/2-inch o.d. bearing on a 1/2-inch straight bit, to trim the material to size, you can then put the same bearing on a bulldoze bit with a large diameter of 1-1/2-inch diameter, and trim the bull nosed edge to the template.
You have to remember, that the 20,000+rpm a router guide bearing is subjected to, is quite high, and as a consequence they have a limited life. The bearing frequently needs to be replaced before the bit wears out, or even dulls to the point it needs sharpened if you are cutting relatively soft wood, and avoid man made sheet goods.
I seriously suggest you buy a copy of, "Woodworking with the Router", by Bill Hylton, and read through it. I usually tell people to try to find most books through their library rather than buy them, but this book is a reference I think anyone who owns a router should have in their shop. He answers lots of beginner questions, and even answers the ones a beginner doesn't know enough to ask yet. It also includes plans for a good router table, or three, an assortment of useful jigs, and fixtures. There are some very creative techniques explained, (such as wavy glue lines), as well.
That's the one. It's handy.
I have checked my bit in the collet as you suggested. There is about 1/4 inch left outside of the collet when the top of the shaft is flush with the top of the collet. So far, the bearings that I have seen are 3/16 inches high, so that would leave 1/16 inch for the stop collar.I see your point about replacing the bearings on bits, both for wear and for customizing the profiles.My local library has a copy of the book that you mention. I will probably evaluate it before buying.Thank you again for your assistance.
A full bullnose bit has no bearing, but you could use a 3/8" quarter round over bit with bearing from top and bottom. some sanding might be needed. This wood is prone to "shatter" so take light cuts.
Hello USAnigel.When I first encountered this issue, I considered using a quarter round bit. I could make the first pass easily. The problem came when I flipped the piece over and made the second pass. The first pass on the top surface removed the material necessary for the bearing to ride against, so I was in a freehand situation again. If there was a way to temporarily fill that gap to give the bearing a resting surface this would work for me.Thank you for your suggestion.
You can find a Bullnose with bearing at http://www.pricecutter.com . Part number P14-3212 ( 1" )
Work Safe, Count to 10 when your done for the day !!
Bruce S.
Hello BruceS.I receive Price Cutter catalogs from time to time. I will check them out.Thanks for your suggestion.
Hi,Jandmayra;
Check the Lee Valley cat. part no. 16J94.03, an adjustable bullnose bit, 1/2" r., top bearing
http://www.leevalley.com Hope this works, Boater
Hello boater.I like Lee Valley and have dealt with them on multiple purchases in the past. They are a good company. I appreciate your suggestion. I will take a look at the bit.Thanks.
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