Adjusting groove & dado widths.

rstermer · 06-07-2009, 08:59 PM

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

**bobj3** · 06-07-2009, 09:32 PM

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.

=========

Quote:

Originally Posted by rstermer

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

rstermer · 06-07-2009, 11:33 PM

Quote:

Originally Posted by bobj3

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.

=========

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

**bobj3** · 06-07-2009, 11:57 PM

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..

======

Quote:

Originally Posted by rstermer

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

rstermer · 06-08-2009, 12:12 AM

Quote:

Originally Posted by bobj3

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..

======

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

**bobj3** · 06-08-2009, 12:39 AM

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..

=====

Quote:

Originally Posted by rstermer

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

Noob · 06-08-2009, 02:21 AM

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

rstermer · 06-09-2009, 10:26 AM

Quote:

Originally Posted by bobj3

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

rstermer · 06-09-2009, 10:27 AM

Quote:

Originally Posted by Noob

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

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

rwyoung · 06-09-2009, 11:13 AM

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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