# Insert hole sizes.



## vaneric (Apr 30, 2010)

I have made a mounting plate for my "table to be" and am not sure as to what size holes to put into the insert plates.
I started with the plate which i felt was the most important part, (apart from the fence) and possibly the hardest to get right. 
I found some fantastic material in my scrap pile. Rigid. Dark reddish brown in colour. 8mm (3/8) thick. Machines well with the shavings being light brown but emitting a rather unpleasant odor. It is similar to a "non-conduction" material I have seen in electrical equipment. Anyway.
I made the insert hole diameter 90mm (about 3 1/2 inches) which is the max my Hitachi M12V can offer. And I machined 2 inserts for different bit sizes holes. Now I need to cut the hole for the bits to come thru.
What are the recommended hole sizes I should make? Are there standards?
I want as much flexibility as possible as I am not sure what the future holds.


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## MuzzleMike (Feb 23, 2010)

My table has a whole that is 3 inches across . I made it that way do to my biggest bit is 2 1/2 inches . People might not like this but it works for me I do not use any bushings with my router unless I am using by hand with my dove tail jig . I hope this helps but I would give your largest bit some room and go with that . If you need more in the futcher you always can make it bigger .

Mike


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## vaneric (Apr 30, 2010)

Thanks Mike
I also made my hole size big. About 3.5 inches.
I have then made 2 3.5 inch inserts which i can make smaller holes in. A little concerned about safety so I though of different sized holes to match the cutters. With a 1/2 inch bit i could use the insert with a 1 inch hole. And a 1 inch bit with the 2 inch hole.
I was just carelessly asking if there were optimum sized holes. I do not have too many bits yet and do not know the "usually" used sizes.
Thanks for your reply.


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## Itbeme (Dec 21, 2010)

Hi

This is the set of eight moulded plastic insert rings that i bought for my Insert Plate - 54mm, 51mm, 47mm, 41mm, 34mm, 22mm, 16mm. 


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http://www.rutlands.co.uk/workshop-&-power-tool-accessories/routers,-tables-&-lifts/router-table-inserts/TLRSETML/set-of-8-twist-lock-rings---moulded-plastic
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Dai


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## vaneric (Apr 30, 2010)

Perfect Dai. Thanks.
A full range would be the safest. I can work it from here.


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## Titus A Duxass (Jan 6, 2010)

Vaneric, for information - your plate material is Phenolic sheet. I use the same for my plates.


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## vaneric (Apr 30, 2010)

Ok. Tightasa
Have seen this word frequently but not sure what everyone is refering to.
Fantastic material for the job.

I really enjoyed machining it.
Although does not machine as well with a 1/4 inch shank cutter. Vibrates a little.


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## BigJimAK (Mar 13, 2009)

Mike, 

Rather than try to tell you how many inserts to make/use and what sizes to use, I'll focus on the question of "why have multiple sizes". 

Many decide based on the obvious: keeping the wood from dipping down into the hole or catching on the far edge but there's another consideration. 

We install zero-clearance throat plates on our table saws to resist tearout. The same is true with routers. How much do you care and how far do you go making/buying inserts? That is matter of personal preference. 



vaneric said:


> I have made a mounting plate for my "table to be" and am not sure as to what size holes to put into the insert plates.
> I started with the plate which i felt was the most important part, (apart from the fence) and possibly the hardest to get right.
> I found some fantastic material in my scrap pile. Rigid. Dark reddish brown in colour. 8mm (3/8) thick. Machines well with the shavings being light brown but emitting a rather unpleasant odor. It is similar to a "non-conduction" material I have seen in electrical equipment. Anyway.
> I made the insert hole diameter 90mm (about 3 1/2 inches) which is the max my Hitachi M12V can offer. And I machined 2 inserts for different bit sizes holes. Now I need to cut the hole for the bits to come thru.
> ...


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## vaneric (Apr 30, 2010)

Great point.
It never crossed my mind to consider this.
Tks.


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## Bar clamp (Jan 13, 2011)

I too am new at this but my router table hole will not allow larger router bits to retract below the surface "I have a tablesaw and router combo" and I have to remove them when cutting on the table saw. Anyhow I use the insert as close to the shank of the bit
1/2 or 1/4 inch size hole. Am I wrong or what??
Also it sounds like the redish brown material could be bakerlite which is an insulator.


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## BigJimAK (Mar 13, 2009)

Steve,

I like to have a hole large enough (using inserts) to pass my largest bit. My largest is 3-5/8", to take Marc Sommerfeld's 3-1/2" diameter bit. My smallest is 1/4", which I use with my 1/8" bits. As to right or wrong, I'll defer to one of the more experienced folks.


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## jschaben (Jun 21, 2009)

Bar clamp said:


> I too am new at this but my router table hole will not allow larger router bits to retract below the surface "I have a tablesaw and router combo" and I have to remove them when cutting on the table saw. Anyhow I use the insert as close to the shank of the bit
> 1/2 or 1/4 inch size hole. Am I wrong or what??
> Also it sounds like the redish brown material could be bakerlite which is an insulator.


Hi Steve, The main issue I would have with your setup (as I envision it) is how much of the bit shank are you able to get in the collet? Depending on the thickness of the router mounting, it sounds like you are only able to get a small amount of shank gripped in there. My opinion would be if not using interchangeable inserts, the hole should be at least as large as the collet nut. JMHO h34r:


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## Bar clamp (Jan 13, 2011)

Hope Mike doesn't mind me useing his thread.
John ,I took the plastic off the bottom of my router and I have plenty of adjustment so my router bit shank will bottom out if I want.
Jim ,the factory hole on my table isn,t large enough for a large bit to pass through amd it is made of cast iron so me cutting is out of the question.
I have to remove the bit when ustin table saw unless item will pass between router bit and saw blade.
Thanks
Steve


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## vaneric (Apr 30, 2010)

Hi Steve
If you only require part of the cutter shape protruding you will need to have a bigger insert hole. For instance if you want a small part of the roman ogee lip in your design you will need to either pack your table surface to come above the unwanted cutter area or lower the cutter below the table surface. 
With a hole clearing only the shank diameter my fear would be if the lock comes loose and the router drops. There would be considerable damage to the insert or the bit would be forced out. I like to think of the worst possible scenario and prepare for that. Safety first.
BigJimAK. Input needed here.
Someone once told me to never be scared of machines but respect them because they can cause serious injuries.
Part 2. Is Bakelite not a black and rather brittle material? The stuff I used also appears to be an insulator but beautifully strong but not brittle.


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## Bar clamp (Jan 13, 2011)

Thanks Mike I never thought of useing only part of the design of a bit but it makes sense.
I think most bits I will be using will fit in the hole in my table but since it is part of me tablesaw I will be looking at building a stand alone router table in the future.
Bakelite comes in different different colors and some of it really looks good. Me being retired from the telecom.ind. have seen many versions of it and some look great.
I think it was used in in making many items including jewelry. Steve


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