# 4mm dado cuts



## DTrak (May 25, 2015)

This isn't exactly joinery but wasn't sure where else to post. I am sliding panels of glass into dado cuts. The glass is only about 2.5mm thick, so I need my dado cuts about 4-5mms thick. I have a common Dewalt plunge router with 1/2" shank. I can't find any bits that are smaller enough. I can use a table saw, but the dado cut has to stop halfway through the wood with a flat bottom edge for the glass to sit on, so the round cut of a table saw wouldnt work. Any ideas? thanks


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## jerryminer (Jun 15, 2014)

You may need a 1/4" collet or a 1/2-to-1/4 adapter to get a bit that small into your router.

Many bit manufacturers offer a 5/32" (3.97 mm) or 3/16" (4.76 mm) in 1/4 shank, such as:

Infinity Tools


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## DTrak (May 25, 2015)

Thank you! You nailed it. I just looked through the router bag and realized it even came with a 1/4" collet! I will buy one of the ones you mentioned.


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## 000 (Dec 9, 2015)

Have you considered a slot cutter. 
I think it would be small enough not to run out the end and also I think would be easier to use.


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## jdh122 (Sep 8, 2010)

I've had pretty poor luck with the very small router bits. You have to take very shallow cuts as they snap off really easily. I'd be inclined to use the tablesaw and then square up the cut with a chisel (although come to think of it, 4 mm is a pretty small chisel).


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## DTrak (May 25, 2015)

I don't know what a slot cutter is. I will look into it.

The problem with a table saw is the round cut gets more and more gradual, hard to square off. I have seen chisels that small though.


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## 000 (Dec 9, 2015)

Here are some images of some.
https://www.bing.com/images/search?q=aMANA+SLOT+CUTTER&FORM=HDRSC2


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## DTrak (May 25, 2015)

Does it work like a router?


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## 000 (Dec 9, 2015)

Yes, you put it in your router and use it the same as you would any bit. It cuts a slot, (from the side) and you can buy the cutters in the different widths (4mm) that you need.
I just used one the other day and it's still in the router. I'll take a picture tomorrow morning and show you what I did.

Here is a youtube video of one being used. 
The one in the video is pretty thin, you would have to find one the size you need.


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## AlaskaGuy (Jan 29, 2012)

Be careful using thin slot cutters. The wings will bend very easily. When one bends it no longer cuts the same size slot.


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## EricTwice (Dec 9, 2016)

Do you have a tablesaw blade that has a square tip grind?

These will give you a flat bottom cut. Consecutive side by side cuts will give you the size needed.

If you don't have one, try an ATB (Alternate top bevel) grind, glue sandpaper on a scrap the correct thickness and just sand out the ridge.


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## waho6o9 (May 6, 2011)

The metric standard set includes the small plow plane with 1/4" blade plus 4mm, 5mm, 6mm, 7mm, 8mm and 10mm blades.

http://www.leevalley.com/us/wood/page.aspx?p=74089&cat=1,230,41182

Have some fun and increase your hand planing skills.


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## splintergroup (Jan 20, 2015)

I'd use a slot cutter bit on a router table, but they do leave the same gradual curve at the end like a table saw blade would do (2" or so diameter versus the TS 10" diameter). This curve can then quickly be cut away with the above mentioned small router bits.


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## SteveMaskery (Feb 18, 2009)

You certainly could use a wing slot cutter and tidy up the ends by hand. You could grind down an old 1/4" chisel to 4mm quite easily.
But is there any reason why you cannot cut the slot right through and then fill the the end with a strip? It would be very easy and, if you did it well, virtually invisible. That's what I would do.


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## 000 (Dec 9, 2015)

DTrak,
Here is the bit I just used. It has quite a bit thicker plate than the thin one in the video above. 
I'm not too worried about it bending as Alaska guy mentioned. (I'm also using a 1/4" cutter).









Here is the slot it cut,









I'm making some sliding closet doors and this is for the track in the bottom.


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## DTrak (May 25, 2015)

Thanks all! I already bought the smaller router bit, so I will try that first, but it's good to know about the slot cutter too. I can't fill in part of the slot because this is all visible. thanks again


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## AlaskaGuy (Jan 29, 2012)

> Thanks all! I already bought the smaller router bit, so I will try that first, but it s good to know about the slot cutter too. I can t fill in part of the slot because this is all visible. thanks again
> 
> - DTrak


Go slow and easy those little bit break easy.


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## bonesbr549 (Jan 1, 2010)

I would order a 4mm bit? if you don't have a 1/4 collet order one.


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