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Discussion Starter · #1 ·
I have to rout a dovetail slot in my router table top for a mitre fence track. I have no idea why they had to make it complicated and dovetail the sides of the alloy track.
I havent done this before and am more than a little apprehensive.

The track is 12.5mm deep, 31mm across at the base, and the angle is 14 degrees.

The only dovetail bit I have is barely 12.5mm. I think I am going to have to cut twice to get the depth. Already my brain hurts thinking about two cuts on an angle.

The bit is also only around 12mm across at the base, so it looks like I will need to make three sideways passes, as well as two depth cuts.

words of warmth and encouragement would be welcome at this stage.
 

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Words of warmth and encouragement from this lot? Surely you jest! >:)

I wonder if you wouldn't be better off just to buy a more suitably sized bit?
 
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Discussion Starter · #3 ·
yeh, I know, I always expect too much.
Thing is, I havent needed to cut this kind of slot so far in my short woodworking life. I dont expect to ever cut another dovetail slot after this, so buying a new bit is going to hurt me in a very private area.

I might have to make a couple (dozen) test cuts.
 

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If you let the bit stick out further than pushing it all the way in, would that help? At least you should get enough depth that way.

A few (dozen) test cuts will reveal all! :smile:
 

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Discussion Starter · #5 ·
This is where my spatial awareness limitations come into play (I am really crap at 3D planning). If I lower the bit and it doesnt cut the top of the wood, and then I raise the bit, because its at an angle i would need to move the guide rail wouldnt I?

Is it simpler to cut high at first. or lower at first? My brain seems to think I would have to move the guide rail regardless. I want to get this right, but do not want to spend a hunk of money on a bit that will never be used again.
 

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Could you define the edges of the slot with a table saw and then clear it out with a router bit?

I haven't seen a miter track that needs a dovetail slot before, that is worth posting a picture.
 

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Bob if you make your first pass with a dovetail bit, then lower the bit, you are essentially defeating the purpose of a dovetail bit, no?

So, use a different bit like a 1/2 inch straight bit to hog out the center of the cut, then two passes with the dovetail bit, one from each side to define the angle.
 

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This is where my spatial awareness limitations come into play (I am really crap at 3D planning). If I lower the bit and it doesnt cut the top of the wood, and then I raise the bit, because its at an angle i would need to move the guide rail wouldnt I?

Is it simpler to cut high at first. or lower at first? My brain seems to think I would have to move the guide rail regardless. I want to get this right, but do not want to spend a hunk of money on a bit that will never be used again.
Have you ever thought about keeping it simple and just buying a track the has straight 90 deg. sides ? by the time you buy router bits and figure it out, you will have more into it than just buying a new track.

Or if you have a "T" slot bit, make a slot that is the right width at the top and slide the dovetail track in.

Herb
 

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Have you ever thought about keeping it simple and just buying a track the has straight 90 deg. sides ? by the time you buy router bits and figure it out, you will have more into it than just buying a new track.

Or if you have a "T" slot bit, make a slot that is the right width at the top and slide the dovetail track in.

Herb
I am going to do an MTStringer here and quote myself.

I can see the reason for the dovetail sides on the track. I installed a straight sided one in my wooden drill press table and was using it to anchor clamps to clamp down my work. I ripped the wood screws out of the table from the pressure of the upward force of the clamping .
I had to use short screws because they went through the top and hit the cast iron of the table below.

But you are going to use yours for guiding the miter gauge, and clamping feather boards , which do not put an upward force on the T-strip, so a square edged one would work OK for you.

Herb
 

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If I understand correctly, for your bit, I agree that you need to make 3 passes to get the correct width. Each pass with your bit can widen the slot the bit's width (at most), which is 12 mm. Set the bit depth to 12.5 mm (but if the shank is less than 12.5mm, you should use another bit, for safety). I'm assuming that you either have a straight edge to run the router along, or an edge guide, or your table has a fence. The 3 passes might be something like:

Pass 1: Let this be the left-most pass. You now have a slot 12 mm wide at the base (the bit width).
Pass 2: Move your straight edge (or guide or fence) over 10 mm to the right. This is the middle pass. You now have a slot that's 22 mm wide at the base.
Pass 3: Move over 9 mm to the right. This is the right pass. After this pass, you now have a slot that's your desired 31 mm wide.

For pass 3, you might want to creep up on the overall width, by moving say, only over 7 or 8 mm and checking the overall width of the slot.
 

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I would also hog out most of the waste with a different bit or a TS and just use the dovetail for the finish cut on either side. You'll need to get the depth correct on scrap before you do the table. As long as the depth is correct you can still adjust sideways a little if you have to if it's too tight. Going down to adjust the fit will give you a stepped cut.
 
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Discussion Starter · #12 ·
Here is the track I have to fit.

UJK Technology Dovetailed Mitre Slot Track - Jig Making - Routing - Power Tool Accessories - Accessories | Axminster Tools & Machinery

I asked why it is dovetailed when it has no force on it, and didnt get much of an answer.
I Dont have a table saw, and the router table top cant be moved.

A good logical step by step from furboo. And vince might well have a master plan.
I definitely need a few practice cuts on this, but it wont be today. We were out very late last night (bed early today is closer to the truth), and I'm in no state to operate a router today (g).
 

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You say your are a Virgin seeking experience!, May I suggest a magazine on the topic, one with pictures and diagrams could add to your lack of knowledge N
 

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This is where my spatial awareness limitations come into play (I am really crap at 3D planning). If I lower the bit and it doesnt cut the top of the wood, and then I raise the bit, because its at an angle i would need to move the guide rail wouldnt I?

Is it simpler to cut high at first. or lower at first? My brain seems to think I would have to move the guide rail regardless. I want to get this right, but do not want to spend a hunk of money on a bit that will never be used again.
Use Rob's 3 pass approach to cut the widest part to size first, then adjust height and rail to cut the narrow part...hogging first is likely required as the bit shaft will get in its own way of cutting the narrow part.

Did I understand correctly that you need to cut deeper than the cutting face of the bit allows...?
 

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The real question is why do you want a mitre gauge on a router table? It is not a table saw. If you want to use a mitre gauge to make sort cross grain cuts the you have ensure that your fence is parallel to the mitre gauge slot. A simple push block is a much simpler and more elegant solution.

Denis Lock - Routing with Denis
 

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Here is the track I have to fit.

UJK Technology Dovetailed Mitre Slot Track - Jig Making - Routing - Power Tool Accessories - Accessories | Axminster Tools & Machinery

I asked why it is dovetailed when it has no force on it, and didnt get much of an answer.
I Dont have a table saw, and the router table top cant be moved.

A good logical step by step from furboo. And vince might well have a master plan.
I definitely need a few practice cuts on this, but it wont be today. We were out very late last night (bed early today is closer to the truth), and I'm in no state to operate a router today (g).
You are correct, this is strictly a miter gauge slot track.

I would prefer a "T" track myself for a router table, they are handier for feather boards which you will use a lot more.
Agree with you on why the dovetail.

Herb
 

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The website says "unique 14° dovetail shaped section which offers extra security for attaching the track." With the screws added, it does seem like overkill.
 

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Discussion Starter · #19 ·
I got the mitre gauge first, for the bandsaw, because it was a bargain not to be missed.. Then i had a brainwave to make it adaptable to the router. Hence the track.
I'm repeating myself, but I dont have a table saw. having a sliding mitre fence on the router table opens up a lot more possibilities for me.
The origins of the shape of the track appears to be a mystery worthy of a dan brown novel.

Yes, the track is a half mm deeper than the cutting edge of the bit I have. Further study today (no I did NOT operate a router!) shows that this bit is just not going to do the job. Damn! My bargain mitre fence is turning into an expensive upgrade.

Neville, I know I'm still fragile today, but not sure how a magazine with pictures could add to my LACK of knowledge? Unless of course if it was a magazine about yachting (g).
 

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I got the mitre gauge first, for the bandsaw, because it was a bargain not to be missed.. Then i had a brainwave to make it adaptable to the router. Hence the track.
I'm repeating myself, but I dont have a table saw. having a sliding mitre fence on the router table opens up a lot more possibilities for me.
The origins of the shape of the track appears to be a mystery worthy of a dan brown novel.

Yes, the track is a half mm deeper than the cutting edge of the bit I have. Further study today (no I did NOT operate a router!) shows that this bit is just not going to do the job. Damn! My bargain mitre fence is turning into an expensive upgrade.

Neville, I know I'm still fragile today, but not sure how a magazine with pictures could add to my LACK of knowledge? Unless of course if it was a magazine about yachting (g).

Bob...also consider cutting it in the 3-step described above but instead of worrying about the .5mm, cut it off with a blade or chisel...that will not require you to realign the bit and fence.

You mentioned your bit wouldn't work...is it the angle or the cutting depth...? (there will be no quitting today)

...and no table saw...you can do all this on the table or handheld with a guide...
 
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