# Adjusting groove & dado widths.



## rstermer (Apr 22, 2008)

If I want to make a groove or dado for a shelf, my woodworking reference tells me I should aim for a snug slip fit, a fit that requires some pressure to force the shelf into the dado. The parts should slide together with just hand pressure and the fit should be tight enough so they won't slide apart unless I pull them apart. Well, if I route a 3/4" wide dado and try and put a 3/4" thick piece of stock into it, it usually requires a mallet to force the two pieces together, if they will go at all. So, some small, and I mean very, very small, adjustment needs to be made to the width of the dado to get the right fit. Just a hair too much and the joint is too loose. Not enough and the joint still won't fit. Here's my question- how should I go about making that adjustment to get that just right fit? Thanks for your assistance.
rstermer


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## bobj3 (Jan 17, 2006)

Hi rstermer

The easy way is to run the stock though the planer to make it a true 3/4" thick, short of that you can use a T & G bit set to made it the true size like 1/4" wide for the ends of the stock and 1/4" slot to fit it in..

You can play with the slot but not all stock is a true size unless you make it so, in one way or the other. 

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rstermer said:


> If I want to make a groove or dado for a shelf, my woodworking reference tells me I should aim for a snug slip fit, a fit that requires some pressure to force the shelf into the dado. The parts should slide together with just hand pressure and the fit should be tight enough so they won't slide apart unless I pull them apart. Well, if I route a 3/4" wide dado and try and put a 3/4" thick piece of stock into it, it usually requires a mallet to force the two pieces together, if they will go at all. So, some small, and I mean very, very small, adjustment needs to be made to the width of the dado to get the right fit. Just a hair too much and the joint is too loose. Not enough and the joint still won't fit. Here's my question- how should I go about making that adjustment to get that just right fit? Thanks for your assistance.
> rstermer


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## rstermer (Apr 22, 2008)

bobj3 said:


> Hi rstermer
> 
> The easy way is to run the stock though the planer to make it a true 3/4" thick, short of that you can use a T & G bit set to made it the true size like 1/4" wide for the ends of the stock and 1/4" slot to fit it in..
> 
> ...


Hi Bob- Unfortunately all the stock is already cut up into fairly small pieces, too small to safely run through the planer, but I can sand them, which is what I've done in the past. 
But, what I was wondering was whether there is some nifty trick, like using a feeler gauge to reset the straightedge by 0.001" and then taking another pass with the router or some other quick way to adjust the dado/groove width which would avoid the necessity of sanding. I hate sanding. That said, I do have a planer, not the world's greatest, a low end Grizzley, but it works ok, so next time.I'll plan on running the stock through it before I start cutting it up. 
Thanks for the suggestion. It is difficult to get this stuff right without at least some training, whether formal or OTJ , and I've had neither, hence the large number of questions I post looking for advice on questions most would consider pretty elementary. Thanks again, 
rstermer


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## bobj3 (Jan 17, 2006)

Hi rstermer

Small parts are not a big deal in the planer, just use a carrier sled..

I have the Grizzly also and it's works just fine for small or narrow parts..

But to get the slot just right is a hard one with a feeler gauge..you can make a go ,no go sanding block that may help.

Just stick some sand paper to a wood block and pass it down the slot a time or two..that may do it for you..some 60 grit..

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rstermer said:


> Hi Bob- Unfortunately all the stock is already cut up into fairly small pieces, too small to safely run through the planer, but I can sand them, which is what I've done in the past.
> But, what I was wondering was whether there is some nifty trick, like using a feeler gauge to reset the straightedge by 0.001" and then taking another pass with the router or some other quick way to adjust the dado/groove width which would avoid the necessity of sanding. I hate sanding. That said, I do have a planer, not the world's greatest, a low end Grizzley, but it works ok, so next time.I'll plan on running the stock through it before I start cutting it up.
> Thanks for the suggestion. It is difficult to get this stuff right without at least some training, whether formal or OTJ , and I've had neither, hence the large number of questions I post looking for advice on questions most would consider pretty elementary. Thanks again,
> rstermer


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## rstermer (Apr 22, 2008)

bobj3 said:


> Hi rstermer
> 
> Small parts are not a big deal in the planer, just use a carrier sled..
> 
> ...


Hi Bob- Could you post a photo of the carrier sled?
Thanks,
rstermer


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## bobj3 (Jan 17, 2006)

Hi rstermer

I did look for it on the hard drive but I can't find it but it's just a board 3/4" thick MDF two rails 1/4" thick (3/4"wide) on both edges and one 1/4" thick one and about 4" wide on the tail end of the board, it's about 24" long,, all that's needed is to rack up the short boards on the sled and push them into the planner..and just that quick they all come out on the sled the same size.. 

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rstermer said:


> Hi Bob- Could you post a photo of the carrier sled?
> Thanks,
> rstermer


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## Noob (Apr 18, 2009)

You could put a strip or three of masking tape on the edge you are butting up against to move you over a few thousandths. 

Another option is to build an adjustable dado jig. They are easy to make, and they adjust to your wood thickness pretty easy too. 

Here is a link to a free plan: Adjustable dado jig LINK

Here is a vid of one being used that is similar to that jig (scroll down to "See it work"): Dado jig vid LINK


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## rstermer (Apr 22, 2008)

bobj3 said:


> Hi rstermer
> 
> I did look for it on the hard drive but I can't find it but it's just a board 3/4" thick MDF two rails 1/4" thick (3/4"wide) on both edges and one 1/4" thick one and about 4" wide on the tail end of the board, it's about 24" long,, all that's needed is to rack up the short boards on the sled and push them into the planner..and just that quick they all come out on the sled the same size..
> 
> =====


Thanks for the description, don't need a picture as your description is quite clear. I do have to admit, with only those strips to hold them in place it amazes me that the parts aren't spit out by the planer knives.

rstermer


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## rstermer (Apr 22, 2008)

Noob said:


> You could put a strip or three of masking tape on the edge you are butting up against to move you over a few thousandths.
> 
> Another option is to build an adjustable dado jig. They are easy to make, and they adjust to your wood thickness pretty easy too.
> 
> ...


Noob- Thank you for those links, very helpful.
rstermer


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## rwyoung (Aug 3, 2008)

There is yet another variation of the dado jig in a video at Wood Magazine. I really hate their new viewer but if you go there, find the on-line videos, then find the collection concerning the router you can watch it. Getting a direct link with their new viewer is a giant pain in the butt.


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## Eoin (Jun 6, 2009)

Hi.

I'm horrified at the idea of using a carrier sled through your planer without at the very least ensuring that the pieces are firmly adhered to the sled with double sided carpet tape and then wedged at the sides and end. That is a very dead planer just waiting to happen. If your pieces are shorter than the distance between the in- and out-rollers, you WILL sooner or later have an accident, carrier sled or not. 14 inches is the minimum we will ever put a piece through a planer in our (professional) shop.

I really don't think you can be precise enough ajusting your slot with a router. A few thou too much and you've ruined it. Bob's sander block method is probably the best. Use a long block (8 to 10 inches long). By that method, you can aim for an arrow shaped slot (where it's slightly wider at the starting end by a thou or three) so that the shelf will slide in all the way when glued. Not so much that it rattles, though. You definitely shouldn't need to hammer it dry - with glue, you'll never get it in. Slow set glue helps here. There is a proper tool for this job - it's called a side rabbet (or rebate) plane, such as the Stanley 98/99 if you can find one or the Lie-Nielsen version of the same, currently available. Set it to take a micro-fine pass. 
Eoin


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## rstermer (Apr 22, 2008)

Eoin said:


> Hi.
> 
> I'm horrified at the idea of using a carrier sled through your planer without at the very least ensuring that the pieces are firmly adhered to the sled with double sided carpet tape and then wedged at the sides and end. That is a very dead planer just waiting to happen. If your pieces are shorter than the distance between the in- and out-rollers, you WILL sooner or later have an accident, carrier sled or not. 14 inches is the minimum we will ever put a piece through a planer in our (professional) shop.
> 
> ...


I tried working on the groove/dado with a file and sandpaper. That process works, but the joint produced isn't very good looking, as it is impossible to widen the groove/dado uniformly, or perhaps I should say impossible for me to do so uniformly, the groove/dado ends up wider on the ends than in the middle when I do it, no matter how careful I try to be. Sanding the shelf, as suggested by Bobj3, seems to work best, as the ro sander rapidly takes off enough so the parts will mate up. 10 seconds on each side was enough to make mine fit, but recognize other's mileage may vary depending on the sander used, the paper and technique. That said, if one was working with a very thin veneer, sanding the shelf could be a problem too, it doesn't take much to sand through the veneer. Thanks for your input.
rstermer


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## fasttruck860 (Feb 18, 2008)

It's worth while to make a dado jig. I build the woodsmith one linked to in an early post and it works great. I use my stock to adjust the width of the dado and that's it. After using it a few times you will learn that you have to fine tune one area or another, but once your past that you don't have to think too much. I just built a book shelf with it and nothing but smiles when it came to the fit.


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## istracpsboss (Sep 14, 2008)

Do you need one of these? Dakota Micro Dado Maker - Metric (DK1016) - Buy online from Rutlands.co.uk

This is from a UK supplier but I've seen them in US catalogues too.

Cheers

Peter


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## istracpsboss (Sep 14, 2008)

Infinity Tools claims an exclusive ! Obviously not! I've seen them on the China dealers' sites. Precision Router Dado Jig-Carbide Router Bits | Router Bit Sets | Shaper Cutters | Saw Blades | Planer Knives | Jointer Knives | Infinity Cutting Tools
I got mine from Rutlands when they were on special offer. Nicely made and came in a wooden box.

Cheers

Peter


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## bobj3 (Jan 17, 2006)

Hi Peter

Very nice jig or make your own 

see below


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istracpsboss said:


> Infinity Tools claims an exclusive ! Obviously not! I've seen them on the China dealers' sites. Precision Router Dado Jig-Carbide Router Bits | Router Bit Sets | Shaper Cutters | Saw Blades | Planer Knives | Jointer Knives | Infinity Cutting Tools
> I got mine from Rutlands when they were on special offer. Nicely made and came in a wooden box.
> 
> Cheers
> ...


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## jschaben (Jun 21, 2009)

fasttruck860 said:


> It's worth while to make a dado jig. I build the woodsmith one linked to in an early post and it works great. I use my stock to adjust the width of the dado and that's it. After using it a few times you will learn that you have to fine tune one area or another, but once your past that you don't have to think too much. I just built a book shelf with it and nothing but smiles when it came to the fit.


I built that jig and it worked superbly on the first try. I was inlaying 6" stainless steel rulers into my router table top and it worked perfectly. :happy: The scales were an odd width, 11/16 or something like that.


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## istracpsboss (Sep 14, 2008)

bobj3 said:


> Hi Peter
> 
> Very nice jig or make your own
> 
> ...


Hi Bob

Interesting! I was trying to figure out the adjustability and wondered if the holes were differentially offset from the baseline?

Cheers

Peter


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## bobj3 (Jan 17, 2006)

Hi Peter

Thanks, the holes are in place to let the chips out,it slides down the clamp bar and to adjust it,just unclamp it and move it over very quick and easy. it can be used for 1/4" slots to ~ , I use a business card the norm for that fine tweaking adjustment..lets; take 3/4" MDF stock, make the 1st slot and move it over by a business card,,then reclamp it, make one more pass ,then it just pops in without any sanding.. 

========



istracpsboss said:


> Hi Bob
> 
> Interesting! I was trying to figure out the adjustability and wondered if the holes were differentially offset from the baseline?
> 
> ...


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## levon (Sep 14, 2008)

bobj3 said:


> Hi Peter
> 
> Thanks, the holes are in place to let the chips out,it slides down the clamp bar and to adjust it,just unclamp it and move it over very quick and easy. it can be used for 1/4" slots to ~ , I use a business card the norm for that fine tweaking adjustment..lets; take 3/4" MDF stock, make the 1st slot and move it over by a business card,,then reclamp it, make one more pass ,then it just pops in without any sanding..
> 
> ========


hi BobJ

ive seen those clamps with the accessories advertised. do you remember where you got yours. at some time ive got to get a straight edge clamp guide. i thought maybe a 50 inch one. ?

p.s. i see holes to mount the router, but couldnt you use it with an 1 1/2 guide alone?


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## bobj3 (Jan 17, 2006)

Hi levon

Clamps from Rockler and HD ,,30",50",74",96" the ones I have on hand 

No need for the guides in this type of jig,but it always nice to put the hole in for the guides ( 1 1/2" ) ,it can be used in many other ways..

This is a old jig and it would be best with the guide hole,I'm just to lazy to make a new one 

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levon said:


> hi BobJ
> 
> ive seen those clamps with the accessories advertised. do you remember where you got yours. at some time ive got to get a straight edge clamp guide. i thought maybe a 50 inch one. ?
> 
> p.s. i see holes to mount the router, but couldnt you use it with an 1 1/2 guide alone?


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## levon (Sep 14, 2008)

hi BobJ

if you have an old one that works , why make a new one? i know jig space is getting precious in your shop. lol you have so many there


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## rstermer (Apr 22, 2008)

Peter- Thanks for pointing that out, a very nice jig. I built the jig I was talking about and was able to cut the slots. I made a set of braces out of pine, but decided they might not be strong enough (too many knots), so am in the process of remaking them in red oak. I am waiting for my daisy pin router to show up from MLCS, and will use the ones I made as a paittern for the replacements.

Thaks again,
rstermer


istracpsboss said:


> Infinity Tools claims an exclusive ! Obviously not! I've seen them on the China dealers' sites. Precision Router Dado Jig-Carbide Router Bits | Router Bit Sets | Shaper Cutters | Saw Blades | Planer Knives | Jointer Knives | Infinity Cutting Tools
> I got mine from Rutlands when they were on special offer. Nicely made and came in a wooden box.
> 
> Cheers
> ...


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