# Deep deep router bits



## Sam88 (Nov 9, 2013)

Hi everyone,

This is my first post. I am new to routers and am in need of desperate help.

The job I want to complete is making a square hole 1.75"x1.75" through a round 8" post. (I know the corners won't be perfect but that's not important)

I need to do this about 25-30 times a month so I plan to make a jig that'll give me a flat surface on which I can rest the router on. Then plunge into the post 2-3 inches then swap to a longer bit until I'm through to the other side.

I was using a joiner who mortice machined the holes but it's costing too much money and time.

My questions are:
Do long router bits exist ?

What would be the best bits to use?


Hopefully you can help.


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## DaninVan (Jan 1, 2012)

Hi Sam; welcome!
The most obvious question, getting back to the most basic, is why the hole needs to be square/rectangular? Is it possible to to use two round holes to eliminate rotational force ( two dowel pins for example).
The second is how precise the shape needs to be? An 1 1/2" hole could easily be squared up with a reciprocating saw to take out the corner material...not saying every one will be a model of precision, mind you.


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## Sam88 (Nov 9, 2013)

Thank you for the speedy reply

I am very new to woodwork so please forgive my lack of knowledge I'm not sure on the technique of using dowel pins, if you could link a YouTube clip I'd appreciate it. Here is my video that might help describe my router intentions: YouTube video name: "King fu wing chun wooden dummy stability test" (would let me post a link)

I make wing chun training dummies. So the holes need to be square and straight but size is a little negotiable.


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## jdowney (Oct 9, 2010)

A 3" cut length plunge bit is about the longest I've ever seen.

Two options I would consider before trying to rout the whole mortise.
1.) Makita chain mortiser - expensive tool, but it would do your job really fast. You would still need to cut from both sides with one.

2.) Template rout the first inch or two of each side of your mortise. Then cut the remaining waste out with a forstner drill the same diameter as your router bit (you'll probably need a shank extension bit too). Clean up as necessary with a sharp chisel. This is much slower than the chain mortiser and a bit slower than routing the whole thing, but it's going to be a nice clean job and you can get the router bit, forstner bit, and an excellent chisel for about the same cost as a big, long router bit.

If you really want to use the 3" router bit, you can get them just about anywhere. I use Toolstoday and Magnate Carbide a lot. Both should have that bit. It will be 1/2" shank and you may need a shorter plunge bit as well to do the first half of the mortise - depends on the height clearance and plunge travel of your router.

You may yet find a super long router bit - I've found some crazy stuff I needed just by looking hard enough and asking on forums like this one. Recently I got some left hand insert tooling for a carving machine from Her-Saf in California (Might be worth looking at their site to see if they can help with what you need). I never would have found them but for a guy on a forum who knew what they made - google never came up with them using terms like "left hand cut tooling".

So even if you can't find the perfect bit right away, come up with something that will keep your product moving out the door, and keep looking for tooling that will speed up production


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## Semipro (Mar 22, 2013)

Hello Sam welcome to the forum.


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## bobj3 (Jan 17, 2006)

Hi

"router bit " How about a 1/2" one that's 6" long from
JessEm Zip Slot Mortise Mill Loose Tenon Joinery System

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## Sam88 (Nov 9, 2013)

Thanks for all the help,

I was thinking about buying 3-4 routers then setting up the first with a standard router but the the next 2-3 with a router extension bits each one being different lengths using one after another. 

Would this work and is there such a thing as a router extension that can go that far?


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## MAFoElffen (Jun 8, 2012)

I was the oldest son of an oldest son.... long story, but here is some answers for clarity:

There are many variations today, but most have two arms at the shoulder extending at an angle from each other, another arm coming straigh out at the level of the lower chest and one bent leg coming straight out from the level of the hip.

A lot of the dummy variations are how the trunk is secured (or not = swinging) and the shape of the truck... But the placement of the arms and leg is fairly standard.

Traditional construction was standard mortise (squared corners) via drilled holes, that were hammer and chiseled into a traditional mortise, with a matching tenon in the appendage. 

Most variations, the arms are rounded as they extend from the trunk. The legs are sometime rounded and sometimes not, but all have a bend at the knee. This appendage is the only one that requires that there be a mortise. That bend at it's knee creates twisting forces, so the mortise prevents it's twisting.

The arms could be created as big dowels inserted into holes... as there are none of the those forces created in it's use. There is tooling readily available for this if you look at those used for rustic log furnishing.

On variations, some have the holes go all the way through and some do not... and rarer have extending or pivoting arms. BUT most lower priced ones sold today do not have through mortises. They are all usually drilled with large bits and chiseled out with a chisel. After you do a few and build skill at it... the way the grain goes and the pre-drilling... after you do a few, it will be old hat. There is a faster, better way... but it involves using a mortising attachment that attaches to the head of a jointer/planer... (look at combo machines) the bits are longer in length, bigger in diameter, and the overall tooling is more expensive... (Also look at Klein 3/4" long slot mortise bit, 4-1/2" flute) Not really suited to if you only build the occasional.

The only way to do it faster would be to use log furnishing tools to make them round... and pin them with dowels to lock them in... But don't be surprised if someone wanting to learn something traditional, wants something made traditionally. There's an appreciation built there that seems to go hand in hand. Funny how that works...

You can mod the base on a chisel bit mortising machine to set on a 8-9" log... but it would take many holes... so drilling many holes... which ends up taking more time than doing it by hand = drilling and cleaning out by hand. If you are using thorough mortises, a sawzall with help... but it doesn't work well for cleaning out the blind mortises. Going all the way through as "traditional" makes taht appendage easy to put it, lock with a wooden pin... but removable and replaceable it damaged.

Attached is a free ebook I had from the Tiger Claw Foundation on Muk Yan Jong construction.


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## MAFoElffen (Jun 8, 2012)

Sam88 said:


> Thanks for all the help,
> 
> I was thinking about buying 3-4 routers then setting up the first with a standard router but the the next 2-3 with a router extension bits each one being different lengths using one after another.
> 
> Would this work and is there such a thing as a router extension that can go that far?


Just some thoughts... 

The further you "extend" the more the torsional forces at the rear bearing and the less accuracy in following a template or guide... which you are implying using a router and a mortising jig.

Router extensions are usually used in a router table where most all things are "supported"... in so, if not cutting down, at least helping to control those extraneous forces... Right?

I'm wondering the thoughts on routing through an 8 inch log -versus- drilling... What do you think you would gain by that? (That makes that attractive to you?)


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## Eric Grum (Oct 14, 2013)

Have you considered a self-feed drill bit in an extension? Milwaukee, Bosch and Irwin make them, and they sell for a reasonable price. I recently got a three bit set (~1 1/2, 2 1/8 & 2 9/16") for $67 from Amazon. Corners coul be squared-up with a chisel, or as a previous poster suggested, with a recip saw.


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## Sam88 (Nov 9, 2013)

Thanks again for all the posts they are really helpful!!

My biggest problem while drilling was not staying straight. It was really hard to judge as it goes on especially against a round edge. 

For a router I can create a flat surface with a jig to rest the router against that'll give me a more professional finish. And if I use 3 routers with different length
extensions I could get it done very fast. Speed is very important since I work full time and I want this to be more full time so I need to come up with something that'll be fast.

I just am unsure on the best bits to use and what extensions if any there are :/


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## MAFoElffen (Jun 8, 2012)

Since you are still leaning than way, then I would suggest laying out your round with the instructions I posted. The through arms at the top will be laid out just one on top of the other in height, but at different angles... so they miss each other as they pass through the center.

You are going to have to build a separate jig just to support your 8" round stock and keep it steady... maybe just blocks nailed to a laid down post. To jack up and hold it steady?

There's lots of plans on the web for router mortising jigs. Use one you feel comfortable making. I would suggest one that is going to use a guide bushing on the router to follow. 

What you will add to that basic jig design is a base for it to sit steady on a round surface. I would suggest 2 "feet" that will sit bisecting across the round stock... that you can cut a 4" radius out from the bottom side. Mark these with the center line... so that you can line these up with the marked centerline on your mortise in the stock and use ratchet straps to secure your jig to the stock.

I would use a 3/4" straight router bit in a 1/2" Collet plunge router... and use a bigger than OD guide bushing. (Substitute your metric equivalents.) You should give ample clearance between the bit the bushing. Plunge router, because your key is to get depth quickly. Keep a vacuum handy to clear out the shavings.

Here is where there is going to be a thorn in this planned method... I would usually tell someone to use a spiral upcut router bit to create a deep mortise, because you want help in keeping the shavings from loading up the bit. BUT you added a twist to that by wanting to use a collete extension. If the shank on the bit is 1/2", the collet on the extension is bigger in diameter to hold that shank. You are going to have to find out what that diameter is before selecting a bit. For a bit to cut while down in a hole, the diameter of the bit has to be larger than the diameter of the chuck on your extension. So that measurement is going to cause a snowball effect on what other things can be. 

You want the smallest diameter you can get away with, as that effects the bit size and the bushing size. The larger you go, the more material you will have to clean out in the corner of the mortises... Although another way around that is to round off the corners of your tenons (to match it) instead...

For extensions, please read here and make your own decision based on your needs and locale:
http://www.routerforums.com/general-routing/41941-understanding-collet-replacements-extensions.html

As with your past problems noted with drilling, the deeper you go, the harder it's going to be to keep your router level to the jig. Take your time and let the bit help you decide how fast to go (don't rush it). Keep the router's base tight to the jig and the jig to your stock. Usually with a router in wood, rule of thumb says you spin a less than 1" diameter bit at 20,000 rpm, take a 1/4" depth of cut at a time and vary the feed rate rate to the conditions... I don't know if you knew that was the "how fast" with a router. It is not as fast as you are implying in your posts (what you are expecting as a fast solution?), but it certainly does it with quality. Slowed down to that, is that you are going to have to keep the mortise clear of shavings...

This _will_ work... This is your journey, only you can decided what is the best path for you to follow.

EDIT--
After posting this and doing something "else"... another alternative came to mind. I figured out antother way with using only 1-2 routers, 2 bits, one small sized 3/4" guide bushing(s) and... no extensions.

On the previous (above) I still assumed you would go half way down, turn the stock over and do the other side, meeting in the center. (Blending in the center later) 

Using the same technique, you could use a plunge router with a 3/4" guide bushing... a 1/2" spiral upcut router bit... and a Klien 1/2" long flute slot mortise bit. All you would have to do is change the bit (or use another router with that same sized bushing and that bit) and turn the speed down:








These bits are rated for 10000 RPM, for wood and have a 1/2" shank. You can't start out with that bit as they are 5-1/2" overall length (3-3/4" flutes)... With a plunge router up all the way, it still sticks out. So, starting it with a spiral bit would get the mortise down in depth to where you could use it. It would be long enough to get down 4-1/2" before the chuck would be close to the surface of the work.

Trend Machinery and Cutting Tools, LTD (UK) also makes slot mortise bits... But in the UK, under Trend their listed under Trend > Trend Industrial Drilling > Trend Reciprocating Slot Mortise... but I can't find what their shank size is. I get mine (Klein) over here through Laguna.


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## Sam88 (Nov 9, 2013)

Wow, that is a great reply. Greatly appreciated!

I like your "edited" idea and most likely the way I'm going to go, just need to find the right router and the right bits. (Tried search the links you suggested but couldn't find it :/)
I am most likely going to 


round the corners of the arms instead of squaring the holes.

The reasons I wanted to go all the way through in one instead of coming from the other side is due to the trunk being round and it's hard to accurately mark up the back to match the front, any tips would help greatly here.
The problems I face with this so far is: the top cut isn't always straight so 10" down one side might be 10 1/2" Down on the other side. Also I had a template but the trunks diameter varies from trunk to trunk slightly causing a bit effect on where the holes meet up.


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## bobj3 (Jan 17, 2006)

1 PC 1 2" SH 3" Blade Extra Long Straight Router Bit | eBay

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## MAFoElffen (Jun 8, 2012)

On round stock-
To get your starting reference centerline, set the round stock in your made cradle (Holds the round stock steady off the ground (horizontal). On one end, put a level across it. Level. Mark where it meets. Do the same one the other end. Chalk a line between those 2 marks. That is your reference centerline.

Measure and mark out your mortise on the left side. Mark the center of that mortise. Measure down from the end. Tape the circumference of the stock, bisecting that mortise.

Take the circumference measurement and divide by 2. Rotate the stock so the mortise is on one side. Take the result of that circumference divided by 2, from the center of the first mortise around to the other side of the stock and mark. Measure down the first measurement you took from the end to the first mortise... and measure down from the end to your new mark and mark a bisect line.

That is the center of the opposing mortise.

I think I remember those instructions I posted as having that same basic instructions for that, but I think it divided by 4, then you measured around the stock making 4 marks with that measurement. 

If you set you round stock in the cradle I described, with the jig centered... it will go straight down and should meet the opposing mortise. It may be a little off. But then you just blend the two together, either with a bit or a chisel. The important thing that is real visual, is that the outside to the mortises are 180 from each other. If you have to trim to blend them together in the inside, no one sees that. And if the two ends of the mortise are a tight fit to the tenon... It doesn't matter much what is inside between them. (To a reasonable limit.)

Does that make sense?

EDIT--
As I remember about these dummies from about 30 years ago, was that the layout of the left and right arm depended more on the measured distance between the "hands" (ends) of the arm needs to end up as, rather than where it is on the chest (trunk). Is that still true?


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## Sam88 (Nov 9, 2013)

That makes sense and I think that'll work well, I'm just looking around for the right bits as you described (can't find the extra long one) and the right router.

As for the arms, the highest arm should be at shoulder height and the ends should be 1 foot apart. The construction of the whole thing broken down hasn't been too difficult but getting it done fast seems to be the difficult part. 

The main reason for going for the router rather than a large drill bit then chiseling a square is because on the first one I made I "traditionally" chiseled all the way through with my fathers old chisels and now I dislike chiseling somewhat.

Thanks!!


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## MAFoElffen (Jun 8, 2012)

Sam88 said:


> The main reason for going for the router rather than a large drill bit then chiseling a square is because on the first one I made I "traditionally" chiseled all the way through with my fathers old chisels and now I dislike chiseling somewhat.
> 
> Thanks!!


Ah. I see now.

Jigs for drilling straight down also (previous challenge)...

You probably where using a "bevel edge wood chisel." Those aren't made to go very deep or to take off a lot of material at one time. They would be okay for trimming sides if drilled first... because you are trimming straight down the sides of the mortise, but hard to get another angle on it to chip out.

Rather, look at "mortising chisel"... In a bind, I've made some of these from a ground-down large broken screwdriver with a sturdy handle. They are made to go deep and chip out.








Another, sort of even more of a specialty chisel, to trim corners faster, is a "corner cutting chisel".


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## bobj3 (Jan 17, 2006)

MLCS Corner Chisels and Cabinetmaker Chisel
=


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## Tiny (Aug 12, 2012)

A stupid question. What is a "training dummie"?


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## Sam88 (Nov 9, 2013)

Wingchunarts com


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## DaninVan (Jan 1, 2012)

Esko; it's a sparring partner that doesn't hit back... 
https://www.google.ca/search?q=trai...yQMKnYigK964HADA&ved=0CDgQsAQ&biw=950&bih=441


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## jw2170 (Jan 24, 2008)

He does in "Kung Fu Panda"......VBG


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## DaninVan (Jan 1, 2012)

Let that be a lesson to us all, James!


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## MAFoElffen (Jun 8, 2012)

Tiny said:


> A stupid question. What is a "training dummie"?


Was answered but... "One" of my past carpentry apprentices came to mind. (ROTFLMAO!!!)


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