Box joint bit ?

[LCHIEN]

I tried out a box joint bit today just a bit.
Have a new Woodpecker coping sled to go with it.
The finger joint bit is a $25 one from an Amazon supplier, much cheaper than the others brands which start at around $75.

http://www.amazon.com/Adjustable-Wing-Box-Joint-Router/dp/B002VI6XBE/ref=sr_1_1?ie=UTF8&s=industrial&qid=1267314328&sr=8-1-catcorr

Supposed to have 5/32 fingers which is what they measure but the spacing between fingers appears to be 11/64 (1/64th more than the fingers) which makes a loose fit.

Does anyone know if there are some small spacers to remove between the five wings? They call it an "adjustable" bit...

Going to have to take it apart later.

[LCHIEN]

Now that i've taken it apart and made some caliper measurements I know why this bit is a third the price of others...

I wanted to play with a bit like this for making some shallow trays.
It was 1/3 the cost of other similar bits, but i took a chance anyway.
I cut the first cuts, it was a VERY loose fit, for this kind of joint you want a nice snug fit - that's part of the point of buying a bit with all the fingers to cut in one pass.

Well the nominal 5/32 wings should be .156" but measured about .162 and and the resulting slots cut around .172"
The fingers should on a good day measure the same as the above spacing between the fingers, but measured about .142. All measurements around +/-.005 grouping.

So it appears that the wings are a bit oversize and worse not quite planar. Taking it apart, there is a thick spacer between wings and one or two shims (.01 and .02 shims) so I'm going to have to find some .030 stock and make some shims to make more fat fingers to get more snug fitting joints.

I may make this work but for the low bucks but it appears that the machining tolerances are just not there. You have to do a lot of work to tune it up.

[Larryl]

Loring, thanks for the review. Again, it looks like you usually get what you pay for when buying cheap tools.

[LCHIEN]

box joint bit

well, I got the $25 bit all shimmed right, they all fix snugly.
Looking all over for some shim material, turns out some old expired credit cards i had were about .029" so i cut them into shims.

The New Woodpecker coping sled is nice. And i built a new router fence for the occassion, including a good dust port. Once i got it all adjusted, i was able to cut four 3/8" boards at a time - used the extra clamp to hold them together with a backer board as you can see.

http://www.woodpeck.com/copingsled.html

Fortunately I got mine on sale last year when they first came out at the woodworking show.
Because of the extreme height of the bit and the height of the workpieces (1.75"), I had to shim the clamping beam of the coping sled up by 1/4" - you can see the shims between the black beam and the red extruded T-tracks the beam rides on.

In that last picture, the last test fit I missed getting the boards to match height by .010".
To fix that I had to raise the router bit .005", half the difference. That was 1/3 of the 1/64ths (which is .016) marking on the Bosch 1617EVS height adjustment knob... very touchy - but it worked.

[phi1l]

So .. if you have all the shims in the way it came, you could use it for making an interleaved wood hinge?

[JR]

That's a heckuva setup, Loring! Looks nice.

JR

[Uncle Cracker]

Love the stuff Woodpeckers sells. Always very well built.

[Bill in Buena Park]

Looks good Loring. Short of using credit cards... where might you locate the .030 spacers?

[LCHIEN]

Looks good Loring. Short of using credit cards... where might you locate the .030 spacers?

they had some sheet metal in various thicknesses at Lowes but it was outrageously priced. I saw some shim brass on eBay and Amazon but I had to buy a big roll for a lot of bucks. I walked around the house for a couple of days with calipers in hand looking for stuff, I sure hope the plastic doesn't cold flow under pressure...

[LCHIEN]

So .. if you have all the shims in the way it came, you could use it for making an interleaved wood hinge?

(LOL) yeah, it was really, really loose.

[leehljp]

Looks good Loring. Short of using credit cards... where might you locate the .030 spacers?

I got some a long time ago made by CMT (here).
I have the CMT cutter (back in the States.)

[LCHIEN]

yep, Hank, sure enough those CMT shims would have worked, 8mm ID x 14mm OD and .1, .2, and .3mm thick (.3 mm = .011"; .2mm = .008"; .1mm = .004")
I would have needed .030" ~= .3 mm +.3 mm + .2 mm = .031"
or 12 spacers total or about $20 worth of spacers at $1.70 each. I think the scrap credit cards were a bit cheaper.

[Uncle Cracker]

I think the scrap credit cards were a bit cheaper.

Depends on what you did with 'em before you scrapped 'em...

[leehljp]

I think the scrap credit cards were a bit cheaper.

They were cheaper back in the late 90's for sure. I am also sure it would have been cheaper all the way around to use the credit card's physical properties than its numerical values!

[cgallery]

Nice job, those joints are going to look terrific. Do you cut to the final depth in a single pass, or do you move the fence once or more to get to the final depth?

Also, what are the I.D. and O.D. of the original shims? Are they metric?