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(Apologies for the long post)

Apart from putting finish on guitars, the binding process has been my biggest frustration. My guitars have big arches on the top and backs, both laterally and longitudinally and cutting channels around the upper/lower bouts and waist areas has been very frustrating involving lots of cuts altering both depth and width.

I use a Makita laminate trimmer, which is light enough hand held and comes with a side following attachment that lets me use ordinary router bits rather than those with guide bearings. This has the power, but the base area is too big to follow just the edge (hence the bout/waist problems). The solution is to put a raised area on the base close to the cutting edge of the bit with a very small surface area to follow just the edge. This, however, makes the trimmer very unstable hand held.

Having done some research, Don Williams' jig was the perfect solution to give me stability. I want to have the trimmer moving round the guitar as I think this gives me better control in areas such as the bottom and top of the guitar where purflings have to be mitred. I set myself the goal of producing the binding and purfling ledge in width and depth with just one pass of the cutter.

Getting to the end of making Don's Jig (thanks for the great info on your website Don!!) I realised that I would not have freedom of motion in all of the directions I required. Don's jig can only adjust the angle the trimmer meets the guitar via the movement from the main Lazy Suzy bearing, so if you are, say, going round the lower bout into the waist area then the trimmer stays more or less at the same tangential angle to the perpendicular sides. The round donut on the base means this keeps the trimmer on the top but it bridges longish lengths in places. With the more common arching used on guitars this wouldn't be a problem, but with the degree of arching I have on my guitars the bridging of the donut would not give me a uniform depth binding channel in these critical areas. Hence I needed the trimmer to swivel, to keep the small "follower" on the top/back edge and the routing bit and guide perpendicular to the sides at all times.

I have had to do a modification to Don's design to enable this that you may be interested in - apologies if it has been done before and I have not seen it. I have achieved this by putting another smaller Lazy Suzan bearing in the part of the jig that holds the trimmer. The follower is a small rubber tap washer (real kitchen sink solution this!!). The beauty of it for me is that I can use just the one router bit to cut the binding/purfling channels and adjust the depth and width of cut on the trimmer. I have set it up for a 11mm double flute (I have found this wide enough for all of the binding/purfling combinations I use) and this drops through a 13mm hole drilled in the new base plate.

Here are some pictures:
First an overview:


Then the business end of the jig on the guitar:


More detail from below. You can see the Lazy Susan Bearing and the small rubber tap washer sitting on the edge of the top as the bit cuts:


And finally a shot from below of the plate attaching to the trimmer base and the tap washer:


I did the first "route in anger" yesterday and although I didn't quite meet my target of one cut/pass it was pretty darned close. The area around the lower edges of the lower bout need a second pass with a slightly bigger width of cut, but the jig keeps things so stable that this is not too hard. When I had to do this by hand it was a nightmare. I think the follower could move even closer to the edge of the router bit - maybe even have it with a hollow core that the bit comes through. This would have the top/back pivot point immidiately behind the cutting edge, but the amount of area on the top/back would be very small and there would be a risk of the trimmer dropping off the top. Probably best to leave it as is and do a second trimming cut.

I'll be putting a page on my website with more details of the construction soon if people are interested.

_________________
Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

Yes please Dave! The alternative might be for me to bring my guitar bodies over to you and let you cut the channel for me! I think that the swivel on the trimmer mount is a great idea. See what I mean, you think outside the envelope.

Colin

_________________
I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

Dave that's a great idea. I'm thinking that a solid carbide downcut 1/4"d. spiral bit with a Donut ring similar to Don's with the bit coming thru the center may solve your problem. I have the same trimmer. Bobc38647.2848148148

_________________
Beautiful and unusual tone woods at a reasonable price.
http://www.rctonewoods.com/RCT_Store
The Zootman
1109 Military Rd.
Kenmore, NY 14217
(716) 874-1498

Nice Work Dave

I have the same trimmer too.

I think it's a really great solution for those who want to use a carbide spiral bit. Awesome!

_________________
"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."

Bob,

Thanks for the suggestion. The problem with the donut ring - even if it was much smaller and just surrounded the cutting bit - is that there is a larger area of surface contact with the top/back and it will find the highest pont. In tight areas like the waist and around a cutaway on the upper bout, the higher areas can be very close to the lower ones where the bit is cutting, and so the bit is pulled up higher than it should be. This is why I'm using the tap washer that has a tiny contact area in line with the cutting bit. The problem is if it is too far back on the top/back, it hits a high spot here too in certain places. The balance is to get minimal contact area as close to the cutting edge as possible, but for it still to be enough to sit on the top/back and support the trimmer.

_________________
Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

The more I look at it the more I like it, it all makes such enormous sense. I use a 6mm downcut spiral bit for my binding channel so this would make life very easy! I've just ordered the Dewalt Laminate trimmer for my binding work so I guess I've got to build a Williams/White rig now. Where did you get the Lazy Susan's from Dave?

Colin Colin S38647.5149884259

_________________
I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

Dave,
I don't know if you have anything like our McMaster-Carr in your neck of the woods, but the sell some UHMW flange bearings which might be the perfect thing. You simply look for the I.D. you want, and then it has a small amount of material outside that. Look for part 57785K38 as an example here. This one has an ID of 1.25", and 1/8" surface to rid the top/back. But they make them smaller too. You can also custom-turn one from UHMW or nylon, making the hole just big enough for clearing the bit, and give say 1/4" of surface to ride the top or back. But frankly, what you have looks like it works too.Don Williams38647.3994907407

_________________
"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."

Colin,

I'm fortunate to have Isaac Lord here in High Wycombe, but they do mail order. Look here. I used the 300mm round bearing for the main one as per Don's jig, and the 150mm square one to hold the laminate trimmer. The Makita fitted nicely into the centre and after trimming a little from the side of the knurl knob, the side guide that came with the Makita fitted in too and could be loosened and tightened. You'd have to check that the De Walt would fit or find a suitable LS bearing.

_________________
Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

Don,

Do you have a picture of what one of these things looks like? How does it attach? If it spins with the router then it might make some "interesting" patterns on the top/back.

I'm not sure we have similar suppliers here but once I figure out what it does I have plenty of contacts/relatives in the States that could get one for me and send it

_________________
Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

Dave the donut I'm thinking of would not be flat but conical so that only the area closest to the bit would touch the top or back. Very similar to your washer but with the bit coming thru the center. It can be made from the UHMW but much smaller in diameter.

_________________
Beautiful and unusual tone woods at a reasonable price.
http://www.rctonewoods.com/RCT_Store
The Zootman
1109 Military Rd.
Kenmore, NY 14217
(716) 874-1498

Unlike Colin who obviously has much more insight than I, the more I look at this the more confused I become.
I'm haveing troubles with:
1) the problem in question.
2) what the fix is.
so basically, the whole thing is going over my head. Anyone up to the task of trying to explain it to me in 3rd grade terms?

Hi Colin

Axminster keep Lazy Susan bearings in a variety of sizes.

Axminster Lazy Susan

Paul

It is only of benifit if you wish to use the type of trimmer that has a built in follower (The advantage of this is you can use straight bits. the additional bearing allows you to turn the trimmer so the guide bearing always sits snug and straight to the side of the guitar.

Dave please correct me if I have any of this wrong.

The UHMW flange bearing is really a bushing in my mind. Not to replace the small lazy susan at all, but to bring the part that lays on the top or back closer to the bit, bring more accuracy. But I don't think it really needs it with your design.

Paul,
What this does is allows the use of the finger bearing attachment which is a stock item with the router. You can usually getr a cleaner cut with a spiral bit than with the large rabbet bits we use such as the StewMac or LMI sets. Dave's secondary lazy susan allows the router to rotate around the guitar body so the the follower bearing can always be facing the side. It's a very nice design actually...

_________________
"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."

[QUOTE=Dave White] Colin,

I'm fortunate to have Isaac Lord here in High Wycombe, but they do mail order. Look here. I used the 300mm round bearing for the main one as per Don's jig, and the 150mm square one to hold the laminate trimmer. The Makita fitted nicely into the centre and after trimming a little from the side of the knurl knob, the side guide that came with the Makita fitted in too and could be loosened and tightened. You'd have to check that the De Walt would fit or find a suitable LS bearing.[/QUOTE]

Dave, the DeWalt base is 90mm square I believe that is the same as the Makita. Thanks again, I love it.

Colin

_________________
I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

Dave how about you cut a small circle of perspex drill through the centre and glue around where the cutter comes through, if you don't have the facility to cut it I've got some hole cutters that would do the job, I could cut it and put in the post to you.