Thread: help for setting depth of cut on incra system

I may be misunderstanding this but I think you need to drop your bit lower, so the top edge of the bit is closer to the table. It MIGHT be that what your missing is that dropping the bit will widen the tails effectively. Hae you tried dropping the router down by the gap above the cut ?

The loose joint is a common problem but dropping the bit usually works. The other possible problem is the spacing is too far from your bit size to compensate, but you say you chose a spacing that was listed as appropriate for the bit ?

Very good document by the way, made the problem pretty clear.

I hope this is of some use.

Hi,
Disagree but only because I had instructions to pull .
Otherwise I would have agreed with Damian.
Also my instructions states:
For the: DOVK (template for choice of joinery)
Use the: DOVJ (template used to set depth of cut)
Mine is several (20?) years old so they may have issued new instructions.
Attached is a pdf for setting the height.
Mike (Not the person who posted the box but I hope this helps mate)

Hint: Once set properly, mark the wood sample and keep it for future use.

Consider raising the bit half the dimension of the gap, and increasing the spacing between cuts, which will make the tails wider. Just a thought.

Yep, raise to tighten, sorry brainfade. The only change in the incra instructions now is they get you to do a half cut at the start and only one complete series, that way you can flip your boards and get 4 goes on one pair of boards, and of course it saves making cuts right across the width of the board.

Spacing doesn't have to be bang on but it needs to be close. From the diagram for what it's worth it looks like it's close enough, but of course it's a diagram.

hi all,

thanks for the answer.
The spacing of 7/8" is indeed the one that is for my router bit. I emailed incra in the usa yesterday and they confirmed that this spacing is used for all 1/2" 14 degrees dovetail bit.
I have only raised the bit as per their manual in which they say that if the bit is loose then the bit has to be raised. I raised it so much that it was almost the thickness of the stock.
so raising the bit definitely does not work
For DOVK, there is no reference to DOVJ for the set up but I might try that tonight.
I had different possible solutions to the problem from incra such as wobble in the router collet (I am using a 1/4" shank with a collet in a 1/2" router), etc...

also something I would like to add:
The spacing on the templates between the different cuts is 7/8" in case of a 1/2" 14 degrees dovetail bit.

after trying to set the depth of cut and not succeeding , I increased the spacing between the cuts from 7/8" mentioned in the template to 1". This worked and I could adjust the depth of cut to have a tight fit.
Then I proceeded with the templates and cut half blind dovetails on 2 boards of the same thickness than the stock I am using for the project I am building.
After completing the cuts, I had the same problems, all the tails where too loose and that's because the spacing between the cut is 7/8".
The pdf sent by Mike describes the same method in the current incra manual except that the pdf suggests to make evenly spaced cuts while the manual suggests to move the fence by the recommended spacing (7/8") for the chosen template.

If you've got a vernier caliper, or a ruler and good eyes, measure the width of the cut at the widest point. That'll tell you if your bits are wobbly.

If 1" spacing works and you don't mind the looks that might be the path of least resistance.

Two more pdf's attached. Mine is the Pro but it seems the height adjustment should be the same (the templets are identical). This does show a 7/8 spacing but starting with a negative setting.
Worth a try maybe?
Best of luck with it.
Mike

Two more pdf's attached. Mine is the Pro but it seems the height adjustment should be the same (the templets are identical). This does show a 7/8 spacing but starting with a negative setting.
You will have to scroll over on the first pdf to see the chart for "templet selection for depth of cut"
Worth a try maybe?
Best of luck with it.
Mike

well guys I have found the problem.
When I went to carbatec last week to buy the router, I specifically ask for a 1/2" cut diameter and 14 degrees angle.
Tonight after trying all your suggestions I still had the problem.
I had a cheap 1/2" dovetail bit but did not know the angle so I assumed that it was a 14 degrees. I inserted it, followed the manual and I had no problem.
so obviously the problem was with the new CMT bit.
I looked again at the box and found to my surprise that it is an 8 degrees !
The worse thing is that when at carbatec, they made the mistake once and gave me a 3/4" diameter 14 degrees. I had to go back to exchange it and get the 1/2' 14 degrees.
They made the mistake twice.
I should have double checked again.
The problem now is that there is no templates for incra with a 1/4" shank, 1/2" and 8 degrees.
I know that the spacing to have a tight fit is 1" so I might be able to figure out something from the templates since the spacings between cuts are 7/8" in the case of DOVK template.
Thanks again for your help

Do a search. Someone on this forum posted a link some time back to an incra template generating tool online. You put in your parameters and it does the sums for you.

Also remember the shank size doesn't matter, it's the width and angle that counts.

Sorry you got the wrong bit. Where are you ? If your in brisbane I could loan you a triton 1/2" dovetail bit if it'll help. I've probably got some others I can dig up...

Hi Damian,

thanks for the offer. I am in Melbourne.
I'll buy a new router bit unless I can find this tool you are mentioning