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I am in the final stages of completing my Williams Jig... doing the aluminium attachment pieces. The specs call for a router bit from LMII and bearings to suit my needs. But, I am not sure what bearing(s) I need! Not a specialsit here... whats a good general bearing? (SKU number appreciated). And yes, I realize that bearing choice affects depth of cut... I am using standard bindings from zoot.

Also, as a side note. In studying the Williams design, it appears that the entire weight of the trimmer is held by the 3/16" plate which is attached cantilever fashion to a vertical block of hardwood. Has anybody found this design to be lacking in strength (flexing)? Any other designs? I have ordered the Bosch PR20.

Mike

Mike,
The LMI cutter, SPCPCN, comes with 9 bearings of various sizes. You can also order an additional set, SPCPCNAUX, that has 8 more sizes. I also order some stock 3/8 OD bearings from eBay for even deeper cuts.

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"An adventure is only an inconvenience rightly considered. An inconvenience is an adventure wrongly considered." G. K. Chesterton.

Wasn't somebody on the forum putting together and selling sets a couple of years ago? Who was that? I've got a few common sized bearings from Stew-Mac, but if I remember right, that was a pretty nice set being offered. I'd probably buy one if they were offered again.

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Wes McMillian
Santo, TX
http://www.wesmcmillian.com

Right... what are the "common" size bearings?

Mike

Mike buddy there is no "common" sized bearing and you will need to use a number of the bearings that come with the LMI or Stew-Mac set. Tracy at Luthier Suppliers sells or sold these sets too.

I am not sure of the measurement of the plate since mine is still packed but it is more then robust enough to support the router. Just be sure to bolt down the jig so it won't tip and the guitar holder too so it won't move.

And John Hall makes and sells the Williams Jig - John is Blues Creek - link above.

If you are taliking about the cutter bearing isn't it a 1/4" I.D. bearing? I've always made a plug to press the bearing into and then turn it to the size I need for the binding/purfling ledge. There are so many different possible combinations I'm not sure there would be a standard size.

Tim

Mike, you're better off buying the basic kit to start off with, and see how they work out for binding and purfling scheme you choose. If you find that something isn't quite the right size, you can then order an extra bearing that is the right size. If they don't have exactly the correct size that you need, you can buy a bearing slightly smaller than you need and beef it up with a little aluminum tape (available at Home Depot).

Oh, the mount plate is plenty strong, even though it's only held on by a couple screws into some hardwood. You don't need to make it out of aluminum either, as phenolic or Lexan are much easier to machine and are very strong. I've used phenolic, and it works fine.

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"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
Only badly."

I just might make that base out of Lexan... The aluminum I ordered is quite hard and I do not have the tools for metal work... I did manage the 4 side pieces though.

I am surprised that there is not a "common" bearing for the binding. The bearing determines the depth of the cut, right?

I have the binding: Item Name: Curly Maple w/.020BItem Number: CM_BND_020B from RC Tonewoods.

Mike

Hey Mike

I ordered the Stew-Mac cutter/bearing set just a few days ago. It's $40 or $50 less than the set from LMI.

The reason the depth of cut isn't standardized is because that although most binding stock is about 1/4" tall (unless you're building an archtop), the width varies. For example, I have a lot of .080" binding stock right now. That with my .060" purfling is going to give me a depth of cut at .140". What if you have .070" wide binding and .020" purfling? So you change the bearing based on the depth of cut you need.

How interesting is that? Wonder why the big price difference? Anyways, I have been happy with Stew-Mac service & products, so I will order that.

Thanks!

Mike

Be aware though, and this has been posted here many times before, with the Stew-Mac set you have to cut the purfling channel first because if you cut the binding channel first when you go to cut the purfling channel the bearing can fall into the binding channel.

The LMI set has a longer shank permitting the builder to cut either channel in an order that you desire.

If you are not specific yet on the sizes you need the Stew Mac set should be adequate.....none of their sizes have ever been useful for me though so I've had to order the LMI stuff for quite some time now.
If you get into anything unusual I think you will eventually have to head over to LMI. They offer a much wider range than Stew Mac and thus the greater expense.

I figured there was a gotcha. OK, please for the novice (me) explain the two cuts. Assume I know nothing (a huge truth). I thought there was only one cut.

Mike

Mike, a couple of things....
The stewmac set now comes with a "bushing" (really, a bearing spacer) to help ease the problem. There is MUCH greater choice with the LMI set - it comes with 10 bearings & there are an additional 8 DIFFERENT bearings available. I went for the stewmac set based on price & later wished I'd gone for the LMI cutter & whichever bearings I cherry-picked. (The sets are NOT interchangable- LMI brgs are 3/16"I.D. and stewmacs are 1/4")
Think of the channel as stairs- the first step down (from the top) is low-rise (1/16"?) & cut first (with a small bearing), for the purfling. The second stair is high-rise (1/4"?) cut next (with a large bearing) for the binding.

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Dave
Milton, ON

OK, I get it. If someone was not going to use purfling, then it would be a single binding cut. I am, in fact, going to use purfling (thin ebony strips).

It sounds like the 1/16" purfling cut would not even get into the side. The final binding cut would (and the top too).

Mike

Your last line does not compute!
I'm assuming you have a stewmac catalogue - look at the picture below "plastic bindings" (pg 28?) showing binding & top/side purflings in place on the steps.

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Dave
Milton, ON

Thanks Todd, that is what I was looking for...

Mike

Dave buddy are you saying that Stew-Mac added a bushing that effectively elongates the shank so the bearing no longer falls into the previously cut binding channel if one tries to cut the purfling channel last? If so - good for Stew-Mac

I have an older Stew-Mac set where the order of the cuts is limited. I also have a new LMI set too since I want to do some more creative things going forward.

Yes Hesh, you'll see it in newer catalogues. It's a 3/32" spacer that goes between the bearing & the cutter, & effectively moves the bearing 3/32" farther from the cutter but leaves enough shaft exposed to still capture the bearing. I had them send me one (couple of bucks) last time I placed an order. (Haven't used it, so can't vouch)

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Dave
Milton, ON

Thanks Dave - this is not surprising because Stew-mac is a top notch company!

I have the Stew Mac set and ran into this problem several months back.

When I contacted them to see if they had any advice on how I could accomplish routing the purfling channel after the binding channel was already done, they told me about the bushing and shipped it to me free of charge.

Very nice folks there at Stewart MacDonald

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Thanks,
Blain

http://www.ullrichguitar.com

"89.67% of all statistics are made up on the spot."

Just curious....is there some benefit to doing the purfling step last??
(I've only ever done it as the first step - after flush trimming - & have had no issues)

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Dave
Milton, ON

Maybe but I don't know for sure. But it seems to me that any time you have an opportunity to remove less wood in a single pass the risk would be lower - all other things the same of course such as climb cuts, sharp bit, etc.

How does this work?

Ok, Iget the lazy suzan part, but where do you get that bearing fixture? Are there drawings and specifications for that base?