When to use BUSHINGS vs BEARINGS on a router bits

as i was reading through the comments the other day i came across one that i thought was an interesting question which i bet a lot of new woodworkers have as well i know i had it when i was starting up what's the difference between a router bushing and a bearing guided bit and when would you use one over the other well the bushing is a collar which attaches to the router's base plate surrounding the router bit bushings come in different sizes and are used to guide the cut while using certain jigs and templates a bushing stays stationary while the bits cutting length may be extended or retracted within it they may be used with handheld routers and in some cases router tables as well a bearing guided router bit features a ball bearing either on the end or at the base of the cutter if the bearing is on the end it's called a flush trim bit if the bearing is at the base of the cutter it's called a template bit bearings are used to guide the bit while using certain jigs and templates just as bushings are but while a bushing is larger in diameter than the bit itself a bearing is of the same diameter another way a bearing guided bit differs from a bushing is the bearing must move as the bit is extended and retracted within the router which may make it challenging to use in some situations now let's discuss some of the situations in which you may use a bushing or a bearing this mortising jig requires a bushing it would not work with a bearing guided bit obviously a bearing on the end of a bit would make it impossible for that tip to cut down into the wood if you were to use a template bit with a bearing at the base of the cutter the bit would have to be fully extended at all times so the bearing can ride against the template in such a situation the mortise will automatically be cut as deep as the bit is long you would need different bits for different mortise depths you would also be forced to cut the mortise in a single shot and that can be hard on the bit and the router with a bushing that remains stationary you may extend the router bit in stages cutting the full depth of the mortise a little bit at a time and stopping at whatever depth you like regardless of the bits overall length a dovetail jig presents a similar situation the length of the joint's pins must be equal to the thickness of the mating board you must be able to adjust the cutting depth of the router bit accordingly while still keeping the bushing against the jig's guides this would be very difficult if not impossible with a bearing guided bed on the other hand suppose you wish to trim an edge flush with an adjacent surface the bearing on the end of a flush trim bit is uniquely positioned to make this possible and its precise size ensures a perfect result such flush trimming is a common practice not only in countertop installation but in many other cabinet making applications template routing is also much easier with a bearing guided bit because the larger size of a bushing creates an offset forcing you to make your template smaller than the final product a template bit makes template making much easier while bits with bearings at the base are often called template bits flush trim bits are also used for template routing for example imagine you wish to route a template with a handheld router but the cutting length of the bit is greater than the thickness of the work piece to keep the end of the bit from cutting deeply into your spoil board that's protecting your bench top you might try to raise the bit but that may lift the bearing above the template's edge there are two solutions to this problem you might use a thicker template to raise the router higher reducing the amount the bit will be able to cut into your spoiler board or you could just flip the work piece so the template is on the bottom and use a flush trim bit which has a bearing on the other end you have a similar choice to make at the router table here the overall cutting length of a template bit is immaterial because the excess can simply protrude into the air above the work piece but as you work your way around a template at some point you may find yourself cutting against the grain you cannot reverse your feed direction to get a cleaner cut at the router table because this will produce a dangerous climb cut we have a tutorial about grain direction and router climb cuts that i'll link to below this video if you wish to learn more on that subject but to avoid cutting against the grain in this situation you would have to reverse the grain by flipping the work piece now the template's on top so you must also switch to a flush trim bit with the bearing on the end if swapping router bits mid cut sounds like a pain well they make some bits with bearings on both ends of the cutter sort of a flush trim template bit hybrid you may cut part of the work piece with the template on the bottom and then if the green direction is in the way flip the work piece lower the bit and finish with the template on top i'll put a link to the router bits and bushings i use below this video in case you want to check them out i hope these examples help clear up the differences between bushings and guide bearings see you next time the whiteside family has been making router bits in north carolina for half a century their quality is exceptional their service is fantastic and i like supporting small family businesses that's why my cabinet is full of white side bits and i think yours should be too check them out at the link below this video wait don't go yet if you're new here please subscribe and remember to ring the bell i would really appreciate that give us a thumbs up or better yet leave us a comment i always read them and be sure to check out the latest issue of stumpynub's woodworking journal it's always packed with tips tricks and tutorials designed to make you a better woodworker

Channel: Stumpy Nubs

Views: 27,152

Rating: 4.9873767 out of 5

Keywords: woodworking, stumpy nubs, tips, workbench, table saw, scroll saw, drill press, quick tip, band saw, bandsaw, lumber, hack, hand plane, sharpening, tormek, worksharp, diamond stone, water stone, wood turning, bowls, lathe

Id: ujH33UYOHI0

Length: 5min 41sec (341 seconds)

Published: Sat Jul 31 2021