# dado sled setup.



## chrisbex (Feb 13, 2015)

Hello,


I'm new to woodworking and I have a question. I bought a dado blade set and didn't relise that my saw could only hold up to a 5/16" dado. I want to make 3/4" dado cuts, because I think they look better. I'm trying to make some finger joints on a board with a jig.


My question is how would I build a sled that would allow me to run a 5/16" stacked dado 3 times to make a percise 3/4" dado and let me repeat that action still keeping a percise 3/4" cut for a finger joint.

I'm making bee boxes and previously built them with a standard rabbit joint, but I love the way they look with the finger joints.

Something like this https://www.youtube.com/watch?v=vxpCUb5En90 around the 9:05 minute mark.

Any information how I can build a sled to accomplish this would be amazing. Thanks.


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## hwebb99 (Nov 27, 2012)

Could you put a stop on both sides of the work piece, and just keep the piece between the stops?


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## woodnthings (Jan 24, 2009)

*I would seriously look at a router*

It's not the solution you asked about, but with the right template you'll make them way faster. You can use a template like this to make finger joints or dovetails:
http://www.ebay.com/itm/15-Dovetail...1343904053?pt=Power_Tools&hash=item4181674935


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## Zircon (Aug 1, 2009)

Build your sled as shown in the pictures. Use your 5/16" dado and for a lead screw use 3/8" -16 all thread. 16 stands for 16 tpi or threads per inch. In the photos I am using a 1/10" thick blade and a 10tpi screw. with your setup, you can make any width fingers 5/16" and up in 1/16" increments. For a 3/4" dado, line up the workpiece as shown in the photo. cut. then turn the crank 5 turns which will advance the workpiece 5/16". Then cut again. Then turn the crank two more turns and cut and you will have 12/16" cut or 3/4". Then 12 turns with no cut. Then repeat


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## Al B Thayer (Dec 10, 2011)

Zircon said:


> Build your sled as shown in the pictures. Use your 5/16" dado and for a lead screw use 3/8" -16 all thread. 16 stands for 16 tpi or threads per inch. In the photos I am using a 1/10" thick blade and a 10tpi screw. with your setup, you can make any width fingers 5/16" and up in 1/16" increments. For a 3/4" dado, line up the workpiece as shown in the photo. cut. then turn the crank 5 turns which will advance the workpiece 5/16". Then cut again. Then turn the crank two more turns and cut and you will have 12/16" cut or 3/4". Then 12 turns with no cut. Then repeat


I see someone else has seen the value in a 3/8-16 screw. I wish they came in acme too.

Al


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## hwebb99 (Nov 27, 2012)

Al B Thayer said:


> I see someone else has seen the value in a 3/8-16 screw. I wish they came in acme too.
> 
> Al


You can buy acme threaded rod left or right hand thread. It isn't very expensive. I don't know about the TPI.


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## woodnthings (Jan 24, 2009)

*Check this out*



Al B Thayer said:


> I see someone else has seen the value in a 3/8-16 screw. I wish they came in acme too.
> 
> Al


It shows a *3/4" *X 16 thread rod, larger diameter and more strength if that's what will work better:

*Item No:* 94-17902 
*Pkg. Qty:* 1 
*Price:* $11.10 
*Select:* 

* 3/4-16 X 3 ft. Threaded Rod* 

http://www.pointe-products.com/itemclass/Threaded-Rod-%28SAE%29-Fine-Thread


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## Zircon (Aug 1, 2009)

Al B Thayer said:


> I see someone else has seen the value in a 3/8-16 screw. I wish they came in acme too.
> 
> Al


They make a 5/8-8 acme rod which would work for people working in 8ths, quarters etc. A 3/8" dado and 8 tpi would work well with this jig. I am using a 1/2" 10 tpi acme screw and the action is very good. No backlash and the work pieces actually click together.


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## Al B Thayer (Dec 10, 2011)

Zircon said:


> They make a 5/8-8 acme rod which would work for people working in 8ths, quarters etc. A 3/8" dado and 8 tpi would work well with this jig. I am using a 1/2" 10 tpi acme screw and the action is very good. No backlash and the work pieces actually click together.


Right. That would work. What is your screw threaded into?

Al


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## Al B Thayer (Dec 10, 2011)

woodnthings said:


> It shows a *3/4" *X 16 thread rod, larger diameter and more strength if that's what will work better:
> 
> *Item No:* 94-17902
> *Pkg. Qty:* 1
> ...


I looked at the link but couldn't tell if it was acme thread.

Al


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## Zircon (Aug 1, 2009)

Al B Thayer said:


> Right. That would work. What is your screw threaded into?
> 
> Al


A heavy duty hex nut which you can see in the second picture. It is trapped between two blocks of wood drilled out and the rod passes through them. The blocks are glued to the part that holds the workpiece so the workpiece advances when the crank is turned.

With the 5/8"-8 acme, if you want to advance the workpiece only 1/16", just give the crank a half turn.


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## Al B Thayer (Dec 10, 2011)

Zircon said:


> A heavy duty hex nut which you can see in the second picture. It is trapped between two blocks of wood drilled out and the rod passes through them. The blocks are glued to the part that holds the workpiece so the workpiece advances when the crank is turned.
> 
> With the 5/8"-8 acme, if you want to advance the workpiece only 1/16", just give the crank a half turn.


You might want to look into a connector nut. There are more threads due to them being longer. I just drill an oversized hole and epoxy it in place while it's on the screw. I haven found any nuts that didn't have backlash. 

Al


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## chrisbex (Feb 13, 2015)

Some good information. Can you send me some more detailed pictures so I can get a better idea? I'm going to tackle this project next weekend and get the material together this week.


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## Zircon (Aug 1, 2009)

chrisbex said:


> Some good information. Can you send me some more detailed pictures so I can get a better idea? I'm going to tackle this project next weekend and get the material together this week.


I would like to claim credit for this jig but I copied it from this You Tube video which has a lot of detail. 

https://www.youtube.com/watch?v=5HUxD1Rm6Vg&feature=youtu.be


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## ducbsa (Jul 6, 2014)

Mcmaster Carr has a good selection of acme studs and nuts.


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## subroc (Jan 3, 2015)

Help! Novice question. Isn't the process in the original video for the tenon portion of mortice and tenon joint? It appears many are helping him with a process for a "box joint" not a true "finger joint?"

I am confused.


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## woodnthings (Jan 24, 2009)

*technically you are correct, but....*



subroc said:


> Help! Novice question. Isn't the process in the original video for the tenon portion of mortice and tenon joint? It appears many are helping him with a process for a "box joint" not a true "finger joint?"
> 
> I am confused.


The term joint has been "widened or expanded" to include box joints, probably because they look at lot like fingers.....

A finger joint bit: http://www.toolstoday.com/p-5045-finger-joint-assembly-router-bit.aspx


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## subroc (Jan 3, 2015)

> technically you are correct, but....


Only because I looked it up, never having heard the term "finger joint" before.



woodnthings said:


> The term joint has been "widened or expanded" to include box joints, probably because they look at lot like fingers.....
> 
> A finger joint bit: http://www.toolstoday.com/p-5045-finger-joint-assembly-router-bit.aspx


Thanks for the info.


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## FrankC (Aug 24, 2012)

woodnthings said:


> It shows a *3/4" *X 16 thread rod, larger diameter and more strength if that's what will work better:
> 
> *Item No:* 94-17902
> *Pkg. Qty:* 1
> ...


3/4 - 16 is a common spindle thread on lathes, the small commonly available face plate makes a great nut for projects such as this.
http://www.ebay.com/itm/2-LATHE-FAC...8&pid=100005&rk=5&rkt=6&sd=290896636362&rt=nc

Backlash is a fact of life and is generally only a problem until one learns how to work around it, which you figure out pretty quick machining metal.


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