Bits for cutting box joints

[Wade Lippman]

I have a leigh RTJ400 and will use it to cut 3/8" box joints. They provide a straight bit but recommend using a spiral bit. I don't have a 3/8" spiral bit, but I do have a 1/4" spiral bit. Would it be a good idea to run a 1/4" bit through first and then the 3/8" straight bit. It seems to me that hogging the wood out first will allow the straight bit to do a better job... but what do I know.

[Jim Becker]

.375" spiral bits are very easy to come by and are not expensive. The biggest challenge is accomodating a .375" shank, but 3/8" collets are available for some routers. I see no issue with what you propose to relieve material before the final cut. You'll likely still get a better quality result with a spiral cutter for the final, however.

[Christian Hawkshaw]

.375" spiral bits are very easy to come by and are not expensive. The biggest challenge is accomodating a .375" shank, but 3/8" collets are available for some routers. I see no issue with what you propose to relieve material before the final cut. You'll likely still get a better quality result with a spiral cutter for the final, however.

Whiteside has 3/8" spiral bits with 1/2" shanks.

[Jim Becker]

Yea, true. I now have a "CNC" mind and generally buy and think of tooling differently sometimes. Thanks for the little hint back to reality.

[Edward Weber]

It might help to reduce the waste with the 1/4 bit but as always, it depends.
The spiral bit is recommenced for the finish it leaves, using a straight bit afterwards eliminates that benefit. It may end up being more trouble than it's worth to do two passes.

[Mel Fulks]

Fastest cutter for hogging out is a ‘single flute’ bit . Not spiral.

[lou Brava]

Just curious, but why not just buy an up cut spiral bit ? You can get a good carbide Whiteside one for under 40 bucks delivered on Amazon.
I just ordered a Whiteside 3/16" carbide up cut for 22 bucks get in 2 days (unfortunately) hard to beat Amazon.
But than again depending on wood type & router speed your straight bit may do fine.

[Wade Lippman]

Just curious, but why not just buy an up cut spiral bit ? You can get a good carbide Whiteside one for under 40 bucks delivered on Amazon.
I just ordered a Whiteside 3/16" carbide up cut for 22 bucks get in 2 days (unfortunately) hard to beat Amazon.
But than again depending on wood type & router speed your straight bit may do fine.

I am making them to donate to a charity auction. I might not ever use the bit again. It is tough to spend $40 just to make stuff to give away, when I can use what I have.

[Wade Lippman]

Fastest cutter for hogging out is a ‘single flute’ bit . Not spiral.

I thought that was for corian, but okay, I actually have one.

[lou Brava]

I am making them to donate to a charity auction. I might not ever use the bit again. It is tough to spend $40 just to make stuff to give away, when I can use what I have.

Got it, & Hats off to you for giving to your charity !

[Thomas McCurnin]

Wade,

When routing with 3/8" bits, check your manual. I don't have that jig, but you may need a special guide bushing. Leigh's eBushing is usually 5/8" so a 3/8" bit should work fine. High Speed Steel spiral upcuts are sharper than their carbide counterparts and are only $25 or so. The carbide ones are nearly 3x that price.

[Wade Lippman]

I didn't listen. I should have sprung for the spiral bit.
But... had I followed my original plan, I would have made out better than I did.
I have a 5/16" bit, so I used that instead of the 1/4" spiral. I shouldn't have. It didn't work well.
However the second pass with the 3/8" was fine. So... I think if I had done the 1/4" spiral first, followed by the 3/8" straight, it would have worked.

My wife just looked at it, pre-glue and pre-filler, and thinks they looks great. So go figure. I see the absolute garbage sold for high prices at craft sales and wonder if I need to be a perfectionist.

[Thomas McCurnin]

Yes, Wade you should be a perfectionist. My work and my word is a reflection upon myself and my character. Make it as perfect as you can.