Alternative to the binding router bit bearings from Stew Mac - created 06-09-2004
Solomon, Aaron - 06/09/2004.10:49:23
Does anyone know of a router bit company, etc. that makes a bit/bearing set for routing binding ledges that is a little less expensive than Stew Mac's set? Thanks
I searched for a cheaper alternative unsuccessfully for more than a year before I finally sprang for the StewMac set. It seems expensive, but it is well worth it for the ease of use. Get a Gramil or make some sort of indexed knife to score your top before you cut. The bit is an inch wide and has the potential to cause major chip out in a soft top. I have had no problem with the StewMac bit and chipout on backs or sides. (I haven't had the problem on the tops either, but I've been unwilling to run the experiment without scoring the top first.)
THanks for the input. When you say soft top - I use maple tops or mahogany - you are refering to spruce or cedar?
Cheers
Yes, I was referring to spruce.
Bob - you could give a bit more detail about what you do with the gramil?
I'd like to try this, for the obvious reason (to avoid tearout). Two questions come to mind:
1. how deep do you feel you need to go with the gramil cut. You say "score" the top, but I'm guessing it's a bit more than that? Several passes, etc.?
2. I would think it would be impossible for the line cut by the gramil to be EXACTLY EXACTLY the inside of the channel cut by the router, so do you favor it one way or the other? That is, maybe, kinda, make the gramil cut just a tiny bit less deep than the router will eventually cut, so that you don't end up with the gramil line still showing after the router has done its part. This would imply that the gramil cut is to relieve most of the potential for tearout, but that the router then cuts into "new" wood for that last 1% or so, by which point the risk of tearout is almost nil...
Am I making sense?
Hi Guys,
Whenever I had had to use a purf cutter or gramil to score the ledge lines, here is what I do - in an inconspicuous place, like under the fret board on the top ledge, use the router, set to the depth you want to cut and drop in for about an inch in length. Now use this area to set the gramil to give the same depth of cut - you should be able to get it set to within a thou or two fairly easily. With the hieght of the blade set to about an 1/8, now score the top and back two or three times lightly, going a littel deeper into the top and back each time. now you have it ready to route. I generally dont need to do this anymore since I use a downcut spiral bit, plus route all the ledges in a climb cut fashion with the lam trimmer. Tearout has been almost non existant in this manner. I sometimes need to claen up a spot that Imay not have routered claen enough though, and this is how I set the purf cutter to do it.
I pretty much do what Tony describes. When I miss and have the Gramil set a hair wider than the router bit cuts, I have to spend a bit of time cleaning up the line. I try not to do that. Mike makes perfect sense on that last 1%. I do two or three low pressure passes with the Gramil and don't worry about cutting to the exact depth that the router bit will cut. Note that I use it only for the purfling ledge which I cut first. When I get to the binding ledge, I just do it. No pre-scoring. Also, I cut freehand with a dome-shaped base on the router. If I have a small discrepancy on the cut, I just go back and tilt the router slightly in whatever direction it takes to line things up. Using wood bindings, any small differences are made up when the outside edge of the binding is scraped. I have not yet become close friends with precision.
I've been using the standard rabbeting set from Jesada. I admit to keeping my binding and purfling widths to sizes that will fit in 1/8", 3/16", and 1/4" ledges.
Jesada, CMT, Trend all do the same cuter, and you can order all sorts of bearings. And if the size doesn't fit in some ocasion, you always have the masking tape solution.
Best regards.
Max.
I have the CMT set. I haven't yet found a place to buy extra bearings in incremental sizes.
I use a Freud set which worksd great but you are limited in the sizes you can do. I talked to the folks at Freud DFirectly and they don't sell all the bearing sizes but sugested going to a brating shop and finding something there that would fit.
Could you machine a cylinder to slip over the bearing to make the size you require? Probably not an easy task, but I bet Bill M. could do it!
I investigated getting the bearings at a local bearing shop. For whatever reason, they had to sell to me at the "retail" price which is great when I'm fixing a broken car or a tool, but awfully expensive when trying to build up a small set of odd sized bearings. The price at the bearing shop made the Stew-Mac price quite attractive. The small ones seemed to cost more than the auto-sized bearings.
Jamie, If you look at the picture's of the bearing sets sold by L.M.I. and Stewart Macdonald, that is exactly what they are selling. They are using bearings all of the same diameter, but have different sized precision collars pressed onto the outside of them. In the past I went to a bearing shop(Kaman Bearings),and found out that most, but not all bearings are made in metric sizes, and some have a mix of std. inch size and metric size, on the same bearing. I was looking for bearings with inner diameter of .250 to match the cutters I already have. I only found one there in a configuration usefull to me. I found 2 other bearing sizes I could use, at M.L.C.S woodworking supply (obvious Google search). The bearings in stock at M.L.C.S. had a precision collar pressed onto them. I called L.M.I. and their cutter sets use bearings with an inner diameter of approx.181"(fits 4.5MM mandrel). Stew-Mac says their bearings have .250 inner diameter. If you try to purchase individual bearings that will fit cutters you already have, be VERY CAREFUL to match the R.P.M. rating of the router you intend to use them on. If you have a machinist at your disposal, you can buy common size bearings, and have them fabricate and press on precision collars of whatever size you desire. That is what I will do after I get settled at my new toolmaker(machinist)job. If you don't have a machinist friend, your best bet is to bite the bullet and spend the cash for the Stew-Mac set or the L.M.I.set(which has the most bearing sizes available). Jay B.
Discussion about the cost of these bearing sets, and trying to find a cheap work-around is really silly. What level of quality do you desire to produce in your finished work? Are you satisfied with so-so, or are you willing to INVEST in the right tool for the job, and just do it really well the first time out?
The money I paid for the LMI set - including the auxiliary set of bearings - was made back very quickly, and the increased efficiency and perfection of cut depth paid off immediately. No more screwing around with a set of calipers trying to figure out which bearing goes with how many layers of .010 and .020 purfling and outer binding.
Now, if some of you are absolutely sure that you will only use the exact same binding pattern for the rest of your building career, you can get along with just two bearings and, the StewMac set should take care of that for a lower price but, if you total up all of the time and gasoline you'll spend trying to duplicate a set with a wide variety of cutting depths, you can easily spend twice as much money than if you just save up and buy the right tool.
I aggree with Bill. However, some years ago I bought a 1-3/4" OD Freud rabbet bit and bearing set that would cut 3/16 rabbet with largest bearing. I went to the hardware store and bought some nylon spacers about 2"OD x 1/4" ID by 1/2" thick for dirt cheep. Enlarge the hole with a 1/2" twist drill for 1/4" depth. Because of the nature of nylon, this will produce a tight fit on a 1/2" od (and 1/2" router bearings). Tap a #10 threads onto a 3" long piece of 1/2" rod, (easily done at home with unhardened steel and a little 3-in-1 oil.) Chuck the piece of rod in the drill press, press the nylon onto the end, and secure with a #10 screw". Sharpen a small chisel to a point, and clamp it to the drill press. adjust the table to just below the spacer and moderately tighten it on the post. By lightly taping the table with a hammer, it is possible to get extreemly fine adjustments. Then advance the spindle past the chisel. Take light passes, as this is not the best thing for a drill press. I dont remember what rpm speed worked the best. I was able to to get bearing spacers sized within .001 or so, and make as many as i want. I etched them to label the with of cut they produce. They all run perfecly concentric.
But like Bill said, this took some time, and everyones time is precious. In the end, there is not much to be saved.
There are all kinds of way to "MacGuyver" our rigs and tools. In fact, it's a kick to "invent" something out of crap lying around the shop or, at least spend very little on parts and pieces. The problem only occurs if you take this philosophy to a point of diminishing returns.
To the serious Luthier, whether you make a living at it or not, our tools are an INVESTMENT in the quality of our work. They shouldn't be viewed as a dreaded expense, but a step toward even better work.
A cabinetmaker friend of mine used to laugh at how luthiers would spend so many hours of their time to save a few bucks on a tool.
I totally agree with Bill. I wish I had bought the LMI set about 3 years ago. It would have saved a lot of grief, time and compromise. I hesitated, as getting things to Australia costs about twice as much as you pay in the US. I am delighted to have it now. So next time you are being a cheap skate, consider how CHEAP you are getting it in the USA, compared to many other countries.
A quick note about bearings. I have never had much trouble with them because I used to sell them on a regular basis so I know a few things that might not be common knowledge.They have a bearing size chart in the parts catalog, listing inside and outside diameter for all the bearings in the catalog. So if you really wanted to do it you could find the sizes you wanted.It would be a fair amount of work to do but is not to bad. This does not mean that they would be as good as a Stew-Mac or LMI set. And until I buy a set I won't know for sure. And I might not tell.
This bearing knowledge of mine came in handy when a HVAC guy was going to charge my mother the price of a new induction fan. She was bummed! I looked at the fan, removed about 15 sheet metal screws and pulled it apart. The problem? Two small bearings in the motor. I pulled them out went to the phone and called an auto parts store. They called their warehouse because they did not stock them, but they were there in less than an hour. I put in the bearings for about the price of a few burgers instead of the price of a hundred! Knowedge is power! Take that you bums that might overcharge someone's mother!
They have a bearing size chart in the parts catalog, listing inside and outside diameter for all the bearings in the catalog.
Who's catalog? Any auto parts store?
"Who's catalog? Any auto parts store?"
Just when you think no one is paying attention and it is safe to go into the water!