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Router question - how to measure accurately?

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Forum topic by jesinfla posted 05-01-2015 05:04 PM 1069 views 0 times favorited 21 replies Add to Favorites Watch
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jesinfla

274 posts in 599 days


05-01-2015 05:04 PM

So, I built a router table today with a fence – see below. I’ve never used a router before and thought it would be the best tool to make a dado? channel in a board.

I have a dado blade I bought recently, but it’s a pain to switch blades on my table saw.

Question is – how do you measure/figure out where to put the fence to align the bit with where you want to route?

Example: I’m making a jig saw table and it requires me to route 2 channels 14 inches apart – how do I accurately align the bit so it’s the proper distance from the edge of the board I’m routing?

Right now, I’m doing my best to measure from the edge of the fence to the edge of the bit – but it seems this isn’t so accurate as it relies on my eye sight.

Thoughts?

Thanks as always in advance

-- They said I could be anything... So I became Sarcastic! They also said making drawers is easy... I think they lied :(


21 replies so far

View pintodeluxe's profile

pintodeluxe

4853 posts in 2275 days


#1 posted 05-01-2015 05:12 PM

I think a dado blade on the tablesaw is the best way to make grooves and dados.
I used to consider blade changes a hassle, and planned my work to avoid extra changeovers. Then I timed a blade change from rip blade to a full 3/4” dado stack. It took about a minute.

My tablesaw has a bigger table top than my router table, so I tend to use the dado blade quite often.
Plus, a dado blade has shims to get the fit just right. Even undersized router bits for plywood don’t fit every sheet of plywood.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View Gene Howe's profile (online now)

Gene Howe

8240 posts in 2890 days


#2 posted 05-01-2015 05:34 PM

I totally agree with pintodeluxe. But, to answer your question: Measure and mark where you want the dados on a piece of scrap 1×2 that is as long as your work piece is wide.
Lay the 1 X 2 perpendicular to the fence and close to the bit. Adjust the fence to meet one of your marks. Make your first dado. Then reverse the work and do the same again.

-- Gene 'The true soldier fights not because he hates what is in front of him, but because he loves what is behind him.' G. K. Chesterton

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jesinfla

274 posts in 599 days


#3 posted 05-01-2015 05:45 PM

Thanks guys – seems like using a router is not so much measuring as it is trial and error :(

Guess I have to swallow the pill and go for the TS dado. Haven’t used that yet either, so another new thing for me this weekend :)

-- They said I could be anything... So I became Sarcastic! They also said making drawers is easy... I think they lied :(

View Daruc's profile

Daruc

459 posts in 594 days


#4 posted 05-01-2015 05:54 PM

It’s not that hard.
Get a sample pc the same size as you are going to use.
Measure from the fence what you need. Make a small (1” into the board) cut, pull the board out and measure it. Draw a line on your table where your fence is, move the fence the appropriate amount, run your test pc again going a little farther this time, remeasure repeat until you get it right.
Run all your pcs then repeat for the next grove the same way.

When ever your going to do anything that needs to be precise, you need to make a sample cut first, even if your using the dado on your table saw.

-- -

View Richard's profile

Richard

1898 posts in 2152 days


#5 posted 05-01-2015 05:56 PM

I would most likely use the router handheld with a guide rail to cut those. Measure the distance from the edge of the bit to the side of the router base plate and clamp the guide that far from the location you want the dado and run the the router along the guide to make the cut. Or several people have posted exact width dado jigs that will do the same thing over and over for different size dados.

View bbasiaga's profile

bbasiaga

754 posts in 1457 days


#6 posted 05-01-2015 08:21 PM

i have also ripped a board on my table saw that is equal to the distance the dado is offest from the board edge, and just used that to position the router tables’ fence.

For instance if I wanted my dado 1” from the edge of my board, I would rip a 1” wide strip, lay it against the fence and push it up to the blade until a single piece of paper fit there with moderate resistance. Seems to work.

-Brian

-- Part of engineering is to know when to put your calculator down and pick up your tools.

View jesinfla's profile

jesinfla

274 posts in 599 days


#7 posted 05-01-2015 09:02 PM

great idea about ripping a piece of wood – thanks all – response are all much appreciated

-- They said I could be anything... So I became Sarcastic! They also said making drawers is easy... I think they lied :(

View bondogaposis's profile

bondogaposis

4024 posts in 1813 days


#8 posted 05-01-2015 09:19 PM

Draw the dado on the end of the board and use that to line up the bit. It is not that hard.

-- Bondo Gaposis

View gfadvm's profile

gfadvm

14940 posts in 2152 days


#9 posted 05-01-2015 09:26 PM

Bondo for the win! At least that’s how I do it so it must be right.

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

View EEngineer's profile

EEngineer

1061 posts in 3075 days


#10 posted 05-02-2015 02:59 AM

Thanks guys – seems like using a router is not so much measuring as it is trial and error :(

Well I have never found it so. But, then, I am using a Woodpecker router lift. One of the great features of their router lifts (and their router plates BTW) are rules on both sides of the bit inscribed on the plate with the 0 point at the center of the router bit.

A little quick math that involves the diameter of the router bit and the desired offset of the dado and I set the fence on my router table to these rules dead nuts every time to make dadoes. This is not a failure of the tool – this is a failure with your equipment surrounding the tool.

Not that the Woodpecker stuff is the be all and end all. I frequently have requirements for dadoes past the end of the rules that Woodpecker provided. But, with a little effort and knowing that their 0 point is accurate, I can always measure from the 0 point to whatever I need.

-- "Find out what you cannot do and then go do it!"

View Holbs's profile

Holbs

1372 posts in 1491 days


#11 posted 05-02-2015 03:22 AM

what about using hand held router and dado router jig, instead of table ? i would imagine, time saved from the jig is better than whatever can be done on router table or table saw. maybe.

-- Yes, my profile picture is of a Carpenter Bee! The name is derived from the Ancient Greek "wood-cutter"

View jesinfla's profile

jesinfla

274 posts in 599 days


#12 posted 05-03-2015 02:12 AM

Thanks everyone for the advice – it’s greatly appreciated.

I tried doing a hand held today – I set the board on fire :( Now I know I’m doing it wrong.

Me and my router don’t seem to be getting along very well.

-- They said I could be anything... So I became Sarcastic! They also said making drawers is easy... I think they lied :(

View kdc68's profile

kdc68

2526 posts in 1739 days


#13 posted 05-03-2015 11:21 AM

Fire and power tools aren’t a good combo. If its a struggle to make a cut, then make shallower passes or use another bit. Shrapnel from a failed router bit can cause serious injury.

-- Measure "at least" twice and cut once

View bbasiaga's profile

bbasiaga

754 posts in 1457 days


#14 posted 05-03-2015 11:40 AM

Yeah, you want to set your depth per pass such that you can keep the board moving continuously without hearing the motor strain/bog, and without leaving burn marks on the wood. Straining the motor is bad for the tool and the bit. Going so slow you burn the wood is bad for the bit an the wood.

-Brian

-- Part of engineering is to know when to put your calculator down and pick up your tools.

View jesinfla's profile

jesinfla

274 posts in 599 days


#15 posted 05-03-2015 05:45 PM

Thanks all – I’ve been setting the bit to 1/4” is that too deep? Go to 1/8? Maybe the router is just too old?

-- They said I could be anything... So I became Sarcastic! They also said making drawers is easy... I think they lied :(

showing 1 through 15 of 21 replies

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