# Precise Slot Cutting Bit



## randymang (Aug 28, 2011)

Hello,
I am interested in finding a way to make a fairly technical slot cut repeatedly and with consistent results. 

I am cutting a groove for the lens to sit in on the inside edge of a pair of eyeglasses. The groove needs to be 1/16th" and have a consistent depth of about 1/16"

They eyeglasses are not flat which complicates things a bit but if I could find a bit that was the right depth and width I think I could manage keeping the cut consistent.

Any suggestions on a good bit to use? Would it make more sense to use a cutting disc? I'm new to routers so any advice is greatly appriciated.

Thank You!d


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## Quillman (Aug 16, 2010)

Forget the router unless your glasses are for an elephant.
Use a scratch stock.


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## Phil P (Jul 25, 2010)

Hi Randy

I've seen plastic spectacle frames routed commercially. They use an overhead (pin) router with a very small diameter HSS groover which has a brass bushing mounted against the blade to control the depth of cut. The workpieces were supported on a curved saddle base to accommodate the curvature of the frame and there was a presser foot (rather like that on a sewing machine) to keep the frame hard against the saddle at the cutting point. Not sure how you could reproduce that using a hand router

Regards

Phil


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## Mike (Nov 22, 2004)

Randy, I worked in the machine repair department of DOC which was one of the larger firms in the US. What material are you cutting and what is your project?


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## randymang (Aug 28, 2011)

Phil - That sounds like a great way to do it. What are the advantages of a pin router over a normal table router with router mounted on the bottom? Also, I found a way to put the groove in when the frames are still flat.

Mike - I'm eyeglass frames that are made with 3/16" cherry. I need to put a groove on the inside of them them for the lenses to fit in. 

Thanks!


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## bobj3 (Jan 17, 2006)

Hi

You can get a Dremel router table that may do the job I have one it works well on on small jobs like yours..
Dremel makes many slot cutter bits just for your type of job..

Amazon.com: Dremel 231 Shaper/Router Table: Home Improvement

Amazon.com: Milescraft 1098 Rotary Tool Work Center Router Table: Home Improvement

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randymang said:


> Hello,
> I am interested in finding a way to make a fairly technical slot cut repeatedly and with consistent results.
> 
> I am cutting a groove for the lens to sit in on the inside edge of a pair of eyeglasses. The groove needs to be 1/16th" and have a consistent depth of about 1/16"
> ...


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## Mike (Nov 22, 2004)

BJ has lined you up with the best choice. DOC used a very expensive Dremel type tool for working with frameless lenses. I suggest finishing your cherry with at least 3 coats of polyurethane finish to add strength before trying to fit the lenses. I am sure you know you will have to have the frames finished before you can get the lenses cut. This is required so the focal point is in the correct location. A Triumph Tracer will be required to get a perfect match with your custom frames. One other thing, you will not need a 1/16" slot, only enough for the locating thread on the lense edge; more like a 1/64" slot.


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## TbearFabrication (Mar 28, 2012)

*bit for glasses slot*

Hey, I'm looking to do the same thing in both wood and acrylic. What bit did you use? did anyone try the pin router?

Thanks, 

Travis


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