# Adjustable Finger (not Box) joint bits



## jschaben (Jun 21, 2009)

I bought this bit:
1 PC 1/2" Shank Adjustable Finger Joint Router Bit - eBay (item 130318097637 end time Jul-18-09 11:48:27 PDT)
(you may have to scroll down past the ads to finally get to the bit itself)
and now I am a bit puzzled about the adjustable part of it. I assumed I would be adding or removing cutters and spacers to match my stock. But, I went to test it on some 3/4 and started disassembling it but ran out of threads about 3 cutters down. So, I simply lowered the bit until the top cutter just cut the top edge out of the stock. Is this correct? If so I don't get a very good fit on the matching pieces. Faces aren't flush and the fingers don't bottom out very closely. Is this just because it's a cheap bit? I know the top of the line stuff is up around $100 or so. Am I doing the height adjustment wrong? I am setting the fence to the bearing, then lowering the bit, using the fence for final depth of cut setting. I am testing this thing on 1x pine, end grain cuts at medium (about 15,000) speed and taking about 3 to 4 cuts to get to full depth. 
Just how does the cutter/shim/spacer setup work? In disassembly I was recording: nut,washer/spacer, top cutter (with flat edge), 2 shims, spacer, cutter, and so on. 
Any input would be appreciated.
Thanks


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## Mike Wingate (Apr 26, 2009)

You got that bit at a good price. Look at this link on MLCS to give you some idea of setup for the bit. Good luck.
MLCS Finger Joint, Box Joint, Window Sill Carbide Tipped Router Bits


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## Mike (Nov 22, 2004)

John, I would bump the speed up to about 17 or 18K. This is based on Freuds suggested speed/diameter.


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## jschaben (Jun 21, 2009)

Mike Wingate said:


> You got that bit at a good price. Look at this link on MLCS to give you some idea of setup for the bit. Good luck.
> MLCS Finger Joint, Box Joint, Window Sill Carbide Tipped Router Bits


Thanks for the suggestions guys. Think I'll start playing with the thing. Shims are .008 so I think I will them all out and just use the spacers for 3/4" as the thing wont make the contact shown in the MLCS link. It will leave a very thin finger either at the top or bottom of the stock. Mine is also a reversible cutter and I don't think the MLCS cutters are, I know the one isn't. Mine also doesn't lock down in a staggered array and I think I will try staggering mine. All those cutters hitting the stock at the same time has a tendency to try to suck the stock into the cutter on all but the very smallest pass. Bearing on mine is also pretty useless until I get into the maximum thickness stock as it is running around well below the top of the table. Don't know if I should assemble the bearing in the middle for 3/4". Wouldn't make any sense to assemble it at the very top (bottom) as the one cutter takes the stock out in that area. Will also try a bit higher speed once I get the configuration right.
May be a few days before I get a chance to fool with the thing again as I have some house guests over from N.Z. and need to keep them entertained.:sarcastic:


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## bobj3 (Jan 17, 2006)

Hi John

Put the spacer and shims back in place like they where when you got the bit,,the shims are for the fine adjustment only.. the bit is made for one job so to speak..to joiner long boards together .. 
end to end thing..not box type joints.. 

Take a look at door/base molding and you will see the setup..as far as the speed it comes down to what type of wood you are going to used,,it's a big bit I would suggest 8,000 to 10,000 rpms with a big router in one pass, more than one pass with a 2 HP router..

I also suggest the fence setup below,it will help.. 


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jschaben said:


> I bought this bit:
> 1 PC 1/2" Shank Adjustable Finger Joint Router Bit - eBay (item 130318097637 end time Jul-18-09 11:48:27 PDT)
> (you may have to scroll down past the ads to finally get to the bit itself)
> and now I am a bit puzzled about the adjustable part of it. I assumed I would be adding or removing cutters and spacers to match my stock. But, I went to test it on some 3/4 and started disassembling it but ran out of threads about 3 cutters down. So, I simply lowered the bit until the top cutter just cut the top edge out of the stock. Is this correct? If so I don't get a very good fit on the matching pieces. Faces aren't flush and the fingers don't bottom out very closely. Is this just because it's a cheap bit? I know the top of the line stuff is up around $100 or so. Am I doing the height adjustment wrong? I am setting the fence to the bearing, then lowering the bit, using the fence for final depth of cut setting. I am testing this thing on 1x pine, end grain cuts at medium (about 15,000) speed and taking about 3 to 4 cuts to get to full depth.
> ...


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## jschaben (Jun 21, 2009)

bobj3 said:


> Hi John
> 
> Put the spacer and shims back in place like they where when you got the bit,,the shims are for the fine adjustment only.. the bit is made for one job so to speak..to joiner long boards together ..
> end to end thing..not box type joints..
> ...


Hi Bob, Thanks for the input.
Yeah, joining endgrain is why I bought it. Have no plans for box joints in the near future. Problem I have is the stock thickness. With all the spacers in, I end up with partial fingers at the top or the bottom or both. With the spacers removed, about 6 spacers for the three cutters that would fit into the 3/4" stock, I would pick up about 3/64".
I am running a 2-1/4 hp Freud in the table which is why I was taking 3 or 4 passes. I ran the speed at about 15 but can vary that either way once I get the fingers looking right. Right now, I am using pine scraps until I get the thing set up. Wasn't about to turn a bunch of oak or maple into sawdust till I got it figured out. 
Thanks again


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## bobj3 (Jan 17, 2006)

HI John

I'm not to sure if this will help,but the norm is 2 or 3 cutters are needed for 3/4" thick stock.


"Carbide tipped cutters. 
Make better edge and end grain joints by increasing the glue surface area. 
Ideal for joining particle and composition board as well as solid stock. 
Makes super strong mitre joints. Replaces mortise and tenon in many cases. 
Quick and accurate set-ups. Item #7861 has 2 flutes with eight stagger finger cutters. 
Will join stock from 1/2" to 1-1/4". Item #7862 has three, 3-flute finger cutters with a 1/2" bore. 
Joins 1/2" to 3/4" stock in one pass and 3/4" plus stock in multiple passes. 
These cutters can also be used on a 1/2" shaper"

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## jschaben (Jun 21, 2009)

bobj3 said:


> HI John
> 
> I'm not to sure if this will help,but the norm is 2 or 3 cutters are needed for 3/4" thick stock.
> 
> ...


Hi Bob, 
Right, I looked at those cutters, run about $70-$80. I figured I could just set the bit height to engage the right number of cutters on the thinner stock and adjust for the thicker. The 1/2 - 3/4 bit refered to here is not a reversible bit, bit height needs to be changed. 
Thats where I was coming from with my idea of pulling shims. I figure I have to keep the same number of shims between each cutter or the reversible part wont work.
Most of my stuff will be with 3/4 but I like the idea of being able to reliably end join up to 2x stock and really don't want to buy two cutters if one can do it, thoroughly dislike one trick ponies. 
Thanks again


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## jschaben (Jun 21, 2009)

:happy:
Hi guys and gals!! Got a chance to play with that bit tonite. Took all the shims out (saved 'em) and reassembled the thing. That gave me 3 nice fingers on the 3/4 stock. Played a bit with the bit height and I got the faces to just under 1/64 before I had to drop it. Looks like a 27/32" bit height will give a pretty acceptable joint. Started running at slowest speed, about 8,000 and turned it up until the bit sounded happy. Ended up about 11-12,000. This is the first finger joint bit I have had so still playing with the tecnique but I think I'm gonna be happy with it.
Thanks again for all the input. I may not have taken everyones advice but I appreciated it and the compilation of all the information gave me the right direction to go.
:happy:


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