# Plunge Pattern Bits?



## Doctor Atomo (Feb 23, 2012)

I inherited some odd bits. I've been told they are plunge pattern bits. The point is used to plunge through the material, then follow a pattern on the smooth shank. Above? Below? Both?

I am just wondering if anyone has experience using these bits and could tell me the pros and cons 

The orange one is a 1/2" CMT carbide tipped bit, the small ones are 1/4" HSS.

I have heard they are used in the R.V. industry to cut windows holes etc. in the finished aluminum skinned, insulated panels...

I also have a regular 1/2" (bottom bearing?) pattern bit which I have used and the Robo-Sander pattern following sanding drum for the drill press which I have used to great effect!


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## bobj3 (Jan 17, 2006)

Hi Jubilee

It sounds like you know what the bits are for, the panel bits are used anytime you want to put in a window or door and they are very quick way of doing the job, the trim bit is just that.

On the panel bits you would just use the top of the bit not the shank of the bit.,they can also be used with templates..without the need for a brass/steel guide or bearing on the bit.

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Doctor Atomo said:


> I inherited some odd bits. I've been told they are plunge pattern bits. The point is used to plunge through the material, then follow a pattern on the smooth shank. Above? Below? Both?
> 
> I am just wondering if anyone has experience using these bits and could tell me the pros and cons
> 
> ...


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## Doctor Atomo (Feb 23, 2012)

Ok, I guess I'll try it. 
I am planning on cutting some windows in a play house I built soon. I guess I'll use a router instead of a jigsaw... I guess for templates I can just tack some straight, smooth strips...
Don't know if it'll be any easier but it'll help keep me from cutting outside the lines and it will be a fun experiment. I would rather use my Colt, but I suppose the carbide cutter will hold up to the 1/2" CDX better 

Looking closer it seems self evident the bit rides on the flush part just beyond the point, correct?


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## bobj3 (Jan 17, 2006)

Yep you got it 


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Doctor Atomo said:


> Ok, I guess I'll try it.
> I am planning on cutting some windows in a play house I built soon. I guess I'll use a router instead of a jigsaw... I guess for templates I can just tack some straight, smooth strips...
> Don't know if it'll be any easier but it'll help keep me from cutting outside the lines and it will be a fun experiment. I would rather use my Colt, but I suppose the carbide cutter will hold up to the 1/2" CDX better
> 
> Looking closer it seems self evident the bit rides on the flush part just beyond the point, correct?


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## mstraw0001 (Apr 3, 2012)

good tip. thanks


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