# Precise Diameter Dowel



## TooPicky (Apr 12, 2009)

What would be the best way to turn a dowel with a precise diameter? Do you basically need some sort of mechanical hold for the tool, and a way to move it down the bed, or is there a freehand technique?


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## 9thousandfeet (Dec 28, 2014)

It suspect it will depend on what you mean by "precise", and to no small degree on the diameter and length of the "dowel"

With a bit of practice and a sharp skew it's possible to turn a cylinder perhaps to within a thousandth of an inch or so, if it's not too skinny and not too long, but the task becomes rapidly more difficult as the diameter decreases and the length increases. 
A 2" diameter dowel 6" long is one thing. 
A 1/2" diameter dowel 18" long is a whole different critter.

In general, a freehand technique capable of surprising accuracy is to line up the tool rest absolutely parallel to the lathe bed, then by gripping the tool consistently it can be used it to register the tool position for the final light cuts.


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## hwebb99 (Nov 27, 2012)

It is very difficult to turn a precise dowel, especially small ones. I could easily turn a short fat dowel on my metal lathe, but long skinny dowels chatter too much. Kenbo has a jig to go on his router table that is the best setup I have ever seen.


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## FrankC (Aug 24, 2012)

You could use a dowel maker:
http://www.leevalley.com/en/Wood/page.aspx?p=42331&cat=1,180,42288&ap=1


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## saculnhoj (May 18, 2015)

It does matter a great deal about what size and how long of a dowel. As was mentioned earlier short fat dowels are fairly easy to get close to size with hand tools. Set your calipers slightly over size and using a parting tool make cuts about every inch or so until the calipers drop over the piece. Then turn the dowel down until these marks just barely disappear and you will have a reasonably straight dowel. Then you may need to take more precise measurements and mark with a pencil and then remove these high spots until it's dead on. I use this method for things like baseball bats and rolling pins that need to be pretty close. 
I had to make some 1/2" and 3/8" dowels that were 36" long. Can't turn those on the lathe. Well actually you can turn the 36" if you lathe has a hollow drive spindle and you have a chuck that will hold them. Turn a couple of inches at a time and then extend it out a few more inches and turn some more. You'll need several steady rests to hold the dowel to keep it from flopping once you get more than about 8" exposed. 
To do the dowels above I bough one of the Lee Valley tools. It didn't work worth a squat on the exotic woods I had to turn. Tearout was outrageous. Worked reallly great on some maple I made as a test but ruined bigtime my exotic wood ones. 
There are two methods that work pretty well using a router. One is to simply get a 1/4 round bit of the diameter you need and run the wood through 4 times to make a square dowel round. You can also find half round dowel bits that work really well. 
The method I use is more complicated but allows you to make dowels of any size. It's very hard to describe. I was hoping I had a photo but I don't. What you do is make a jig for your router. The router is mounted in a router table. The jig has about a 2" hole drilled in it and fits over the router bit. (I use a straight sided sharp HSS bit) Now saw a square dowel that is a little larger than the dowels you want to make. Drill a hole in you jig perpendicular to the original hole. Drill it so the square dowel just barely fits. Now directly inline with this drill a hole on the other side that is barely bigger or almost the same size as your final dowel. Chuck the square dowel into a drill. Feed it into the larger hole so it feeds past the router bit. The spinning square dowel is cut as it passes the router bit and then it goes into the smaller hole on the other side and is stabilized. The first inch or two of the dowel will be ragged and torn but after it gets stabilized in the other hole it cuts pretty clean. Of course you'll have some waste on the other end as well. 
Here's a video of a jig that is similar to mine. https://www.youtube.com/watch?v=cu0kCBngxKM


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## TooPicky (Apr 12, 2009)

The dimensions on the part in question is 18" x 1 1/2" +-.


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## hwebb99 (Nov 27, 2012)

I think you wrote your size backwards. I could use my metal lathe to it that. A duplicator would do the same thing. If you are making more than one, a router jig would be by far the best.


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## saculnhoj (May 18, 2015)

Something similar to my router fluting jig would work. I normally use a table attached to the Banjo now instead of the one that fits on the bed of the lathe but either works. It's setting up the fence on the table accurately that is the critical part.


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## Bill Boehme (Feb 9, 2014)

One other factor that nobody has mentioned so far is straightness. The longer and thinner, the more difficult it is to keep it straight. The Veritas jig won't give you straight dowels. String steadies are probably the only solution for really long and thin dowels ... that, and buying them ready made at the hardware store.


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## hwebb99 (Nov 27, 2012)

Buying dowels at the hard where store limits you to oak and birch. The size still is not very precise, and they still aren't straight.


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## saculnhoj (May 18, 2015)

Store bought dowels are often out of round. That's why I started making my own. I used to make a lot of clocks and would use dowels glued into holes to make the numbers. The drill bit (if it's properly sharpened) makes a round hole. The dowels I bought were almost always slightly oval. This left an ugly glue gap. By making my own dowels I not only got whatever species of wood I wanted but also got perfectly round dowels.


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## woodnthings (Jan 24, 2009)

*other methods ......*

on the table saw:
https://www.youtube.com/watch?v=6e9F_1sGOXA

even more simple:
https://www.youtube.com/watch?v=cIv-dhO2fEo


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