Official Luthiers Forum!

I have the complete set from StewMac. 1” bit. Bearing sizes go down to 1/2”. My calculations say I need a .46” bearing. Binding is .125, purfling is .145. Check my math. Where do I get smaller bearings? I need smaller for the purfling ledge cut.

Can you cut the .090 or .060 binding ledge then cut the purfling ledge riding where you've cut for the binding giving you extra depth?

Have you emailed StewMac to see if they sell any other binding bearings?

(Not to hijack your thread but this is the exact reason I switched to the Elevate binding jig because it is super adjustable in both directions for the cuts. I love it by the way, speeds me up a bunch because I don't have anything standard yet.)

0.125" seems quite thick for the binding. Unless your sides are very thick, routing the binding channel would go through the sides and well into the lining. Are you using kerfed or solid lining?

I wonder if it would be physically possible for there to be a bearing smaller than .5" that would fit onto the StewMac cutter shaft which is .25".


EDIT: I was thinking more about the numbers you give above and I'm not clear on how the 0.46 bearing was calculated. Is there more than one StewMac cutter out there? You mentioned that yours is 1". The one I have is 15/16" and the largest ledge it can cut is 0.210" with the 0.5" bearing. To get a 0.270 ledge (0.125 + 0.145), the StewMac cutter I have would need a 0.380" bearing.

_________________
Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

I've never had to cut wide or odd size binding slots but I have one of these on the shelf, just in case.
https://www.thetoolstore.ca/viewItem.as ... =1790&cl=0
In your case, you could use it with a Stew Mac .70" or .72" bearing. That, and a wrap of tape around the
guitar body would get the job done.

Forgot to mention, you can probably get those Freud rabbeting bits at HD and Lowes or other other stores
in your locale, in case you don't already know that.

.125 includes a 6mm maple strip. My binding always sits proud and I scrape back. It’s a look I like.

I get a roll of 1/4” fine line detailing tape at automotive paint suppliers and just add a winding or two to the next smaller bearing till it is right. Just wind in the direction it stays on instead of unwinding it when in contact with the work surface. The fine line tape is thin and uniform in thickness.

Never seems like the bearings are just right. Never had the tape come off the bearing yet.

_________________
Brian R, Wood Mechanic
N8ZED

go to Grizzly and look at the router bit sets
https://www.grizzly.com/products/Grizzl ... hank/H5547
when you need .460 you can't add tape you have to go smaller.
I do a 45 I use .230 for my binding and pearl and purfling
what is your binding scheme ?

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

John, I’ll post pics tomorrow

Something I have done when I want to use a smaller bearing whose inner diameter won't fit over the nib provided for it, is to screw it on below and use the screw to hold it in place. Conversely, when I have wanted to use a bearing with an inner diameter that is too large for the nib I have used the inner ring from a failed bearing as a bushing (along with a flat washer that spans the inner ring of the large bearing to hold it on) to fill the gap.

A less fiddly solution would be to buy one of these sub base attachments and use a 1/4 inch straight (or spiral) bit . Not as nice as the Elevate tool but with a little bit of care works fine (a number of brands make these):

https://www.boschtools.com/ca/en/boscht ... 6-27018-p/

Pretty standard stuff.

binding and maple purfling is .125, herring bone strip is .145

If I'm using tape to fit bearing sizes to purfling/binding schemes I've found self adhesive Conductive Copper Foil Tape, 6mm the best to use.

_________________
The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

At one time I used rebating bit for cutting binding channels, but found the limitations of bearing selection to be problematic. I cobbled together a simple jig using some plexi and a cheap commercial unit similar to the bosch listed above (picture). Elevate makes a very nice jig for doing bindings which I believe is an improved version of a homemade jig usually made of wood. Here is a pinterest page with a similar jig (as well as some other interesting stuff):

https://www.pinterest.com/pin/328551735 ... 0/?lp=true

Here is an eBay seller that seems to be up to his alligator in roller guides if you decide to go that route (they can usually be adapted to fit most trimmers):

https://www.ebay.com/itm/DEWALT-DWE6018 ... SwArNdDSSS

This is so crazy. I need a rabbet bit, 1 1/8” diameter, 1/4” shaft, long shaft. Can’t find it

Hi Mike,
Finding a large rabbeting bit is not that difficult, but a large bit with a 1/4 inch shank will be hard to find. Most large bits have a lot of weight on the cutter so a 1/4 inch shank would be a poor design.
You might try using a slot cutting bit and stacking cutters if you need more cutting depth. Slot cutters can be set up with the cutters and bearings in different configurations and have many different uses.

https://www.rockler.com/power-tools/rou ... outer-bits

The SM bit is 0.925", the LMI 1.00", and there are several 1/4" 1.125 and 1.25" rabbeting bits that should take the LMI bearings (SM bearing will fit the LMI and other small rabbeting bits either with or without a space sleeve); LMI bearings will not fit the SM bit.

Amana sells two 1-1/8" x 1/4" shank insert cutter bits:

https://www.toolstoday.com/v-9848-rc-49300.html

https://www.toolstoday.com/v-13969-rc-49357.html

Timberline sells two 1-1/4" x 1/4" shank bits:

https://www.toolstoday.com/v-8050-260-10.html

https://www.toolstoday.com/v-11627-260-11.html

Home Depot should stock the Freud Diablo DR32100 1-1/4" bit in 1/4" shank:

https://www.homedepot.com/p/Diablo-1-2- ... /202563337

There are many other 1-1/8" and 1-1/4" rabbeting bits of varying quality available in 1/4" shank, but this should get you started. The point made about the instability of 1/4" shanks running on larger, heavier bits is well made...a quality collet is needed, and mounting the bit with as little shank above the collet as necessary will minimize some issues, but some test cuts seem in order to determine whether vibration levels will be acceptable. That said, other than preferring a down-cut skew on the tips versus the provided up-cut (for our application), the Diablo is a good solution when we have to mill wider channels.

Finally, another option is to buy the LMII bit...it manages cuts of 0.230" with the smallest LMII 0.540" bearing, but with a 0.500" bearing from another bit (a common size on guided bits), 0.250" is possible.

_________________
A constellation only takes shape when one maps the whole.
- Beth Brower

Should be able to find what you need here.

https://www.routerbitworld.com/

B

_________________
My memory is so good, sometimes I remember things that never happened.

I thought my stuff came from Stew Mac. I have two bits, one short shank, one long, both 1". did I really get from LMI? Did Stew Mac used to sell bigger bit? Reason I am confused is my current bearing set looks exactly like Stew Mac in sizes. Are bearings interchangeable between suppliers?

Are bearings usable on amana and others?

Definitely, most manufacturers use available bearings rather than having custom sizes made. The ID
Will be the key. Measure the spindle where the bearing sits. The bearings are usually sold stating ID, OD and thickness.
You may even have a bearing supply house locally that has what you need at a fraction of the cost.

_________________
My memory is so good, sometimes I remember things that never happened.

I've used Freud 32-502. Readily available at the orange box, not too expensive. 1/4" shank, 1-3/8 cutter. Rabbets 1/2", 7/16", 3/8" or 5/16" with included bearings, but also compatible with SM bearings for inbetween sizes. You absolutely need to cut the wider binding+purfling channel FIRST. You then make a second cut to cut the binding rabbet.