Official Luthiers Forum!

I bought my new binding trimmer tooling from John. I really like it.
It is so much better than my old way. I just finished doing 2 guitars.
Both of the sides have a pretty good groove from the bearing. Is there a trick to avoid this?
I'm sure someone will say that I am just pushing too hard, but I don't think I am.

You can see the indentation on the top and bottom from the bearing in the picture below.




SteveS39012.9386226852

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

are you sure that your bearing is turning freely?

Steve,
Michael stated the most likely cause. I have found that if you don't push
too hard against the sides and the bearing is well lubricated, you don't
cause those marks. It make 3 passes and go very light each time.   Also,
going to slow seems to cause them for some reason. I think it is more of
a feel thing - as I have done mahogany and walnut before with no
trouble. In other words, they don't happen to me any more after I have
been using that jig for a while now.

The other thing I noticed from your photo is that the plastic shoe that
rides atop the guitar is very rough. Take some sandpaper and round it
over and then smooth with subsequent grits up to about 1500 grit. The
first time I used my Ribbecke style jig, the shoe was rough and its edge
tore some of the grain on my cedar top - nothing permanent but it can be
avoided if you make it smooth.

By the way, I really like the bloodwood binding on that koa guitar - it
looks awesome.

Peace Out,
SimonSimonF39012.9559606481

Steve, Ive always gotten that too and just accepted it. They usually scrape/ sand out without much difficulty.
I'd be nice if someone has an answer for it however.Jim_W39012.9530555556

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Jim Watts
http://jameswattsguitars.com

Does the bearing spin very freely? You may need to "break it in" on some scraps, or by tying the bearing up with some tape and spinning the router for a few minutes.

Also, it can very well be that you're not pressingt he bearing against the side hard enough. If you don't hold it tight enough, the bearing will spin, causing those burn marks we see....

The bearing spins freely. What do you guys recommend for bearing lube.
Hesh, yes the bearing is a bit tilted in that picture. The other guitar was EI rosewood and the bearing was straight for that one. Although the wood was harder, it left the same dent.
Steaming it out sounds like a hot tip.

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

Steve,

I would bet that the bearing is sealed and can't be lubricated.
Please post pics of your further progress!!

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now known around here as Pat Foster
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http://www.patfosterguitars.com

[quote]A little moisture and a MonoKote iron will raise the grain -[/quote]

Somebody builds model airplanes!!!

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Billy Dean Thomas
Covina, CA

"Multi famam, conscientiam, pauci verentur."
(Many fear their reputation, few their conscience)

Steve, is your bearing free and perfectly horizontal? it looks rather tilted from the picture...not perpendicular..

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Peter M.
Cornerstone Guitars
http://www.cornerstoneukes.com

Peter,
The bearing free? Are you kidding? Those things are expensive!   

The bearing is free and was not perfectly horizontal for that guitar. But it makes the groove even when it is perpendicular.



[QUOTE=Billy T] Somebody builds model airplanes!!! [/QUOTE] Me too. I knew just what he meant. Do you fly? I spent some time on Temple hill flying gliders.

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

Hmmm.... I have the Stewmac bearing and bit set and never get any marks.... peculiar indeed!

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Peter M.
Cornerstone Guitars
http://www.cornerstoneukes.com

[QUOTE=burbank] Please post pics of your further progress!![/QUOTE] Well, OK -

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

Getting pretty close!

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Peter M.
Cornerstone Guitars
http://www.cornerstoneukes.com

Very nice work Steve, gorgeous i should say!

Steve those marks are caused by the bearing rotating with the cutter. You can see the burn marks on the Koa. The bearing should not revolve with the bit but just roll as you make your cut. Try watching the bearing while you cut on a piece of scrap wood. As an added precaution you can apply masking tape around the body where the bearing rides.

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(716) 874-1498

Great tip there Bob, i'll remember this for added protection, thanks!

Serge

[QUOTE=Bobc] As an added precaution you can apply masking tape around the body where the bearing rides.[/QUOTE] I was wondering if that was done. Thanks.

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

[quote]Me too. I knew just what he meant. Do you fly? I spent some time on Temple hill flying gliders.[/quote]

   You can't be talking in Pomona could you?

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Billy Dean Thomas
Covina, CA

"Multi famam, conscientiam, pauci verentur."
(Many fear their reputation, few their conscience)

This is one of the advantages of using a bearing mounted on the laminate trimmer rather than the router bit. Unless the bearing is sealed it will pick up wood dust very quickly and bind it up, and turning at 30k revs will certainly burn the wood. If you free hand use a guide-bearing mounted on the trimmer and a downcut bit. If using a Williams/Fleishman jig just add the Dave White modification when using the trimmer based guide-bearing/downcut combo.

Colin

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

Most bearings are packed with a heavy grease that sometimes keep them from turning fast enough to keep up with a router. As Mario suggested, you can run them for awhile to break them in. Another approach is to take out a seal, and soak in solvent to remove the grease. Blow it out with compressed air and then lubricate it with something that is more suitable for higher rpms. I use "speed oil" which you can get a skateboard shop.

[QUOTE=Hesh1956]
I loved the smell of 30% nitro in the morning..... [/QUOTE]

Aha! Sniffing solvents now are we? And in the morning!!! Tisk Tisk!

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I'd like to be able to prove, just for once, that money wouldn't make me happy...

[QUOTE=Billy T] You can't be talking in Pomona could you? [/QUOTE] That'd be the place. I lived in La Verne for about a dozen years and went to Cal Poly Pomona. I spent many hours flying Temple Hill. Do you fly?

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