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Oct 16, 2019 - 10:55:57 AM
402 posts since 1/25/2012

I'm working a neck build and am planning to do a rudy rod for the dowel. Anybody have any recommendations on the right anchor and threaded rod to get (off Amazon maybe)?

I could wander up to local Ace and see what they have some time, but I'm going to be out of town for the next couple days--if I can order something and have it waiting when I get back, I'd rather do that...

Oct 16, 2019 - 11:15:38 AM

Fathand

Canada

11508 posts since 2/7/2008

I use 1/4 or 3/16" threaded rod from a hardware store. You could also use unthreaded rod and thread about 2" on the ends yourself which may look a bit neater but it is inside a "dowel" stick anyways.
The anchor is called a "barrel nut" at my hardware store.

https://www.amazon.com/BARREL-FURNITURE-BOLT-SLOTTED-14MM/dp/B006ZLKOOU

Oct 16, 2019 - 12:59:15 PM
Players Union Member

rudy

USA

14578 posts since 3/27/2004

quote:
Originally posted by crazybilly

I'm working a neck build and am planning to do a rudy rod for the dowel. Anybody have any recommendations on the right anchor and threaded rod to get (off Amazon maybe)?

I could wander up to local Ace and see what they have some time, but I'm going to be out of town for the next couple days--if I can order something and have it waiting when I get back, I'd rather do that...


Details HERE.

Oct 16, 2019 - 1:28:48 PM

12265 posts since 6/29/2005

I make a lot of these.

I don't like threaded rod all that much because when you tighten the tension rod, you can feel it twisting and I always get the feeling it could break from the twisting, which would be a PIA.  I use 3/16" zinc plated steel rod, which you can get at Lowe's and thread about 1 inch of it on each end 10-24—this feels much more solid.

For the anchors, I use either 3/8" round or square aluminum or brass, drill holes in it at the appropriate spots, and thread them 10-24.

Oct 16, 2019 - 4:19:19 PM
Players Union Member

rudy

USA

14578 posts since 3/27/2004

I only use 1/4"-20 all thread.  I haven't noticed any twisting when tightening, but that might be due to the larger size rod.  I wouldn't use a smaller size, but I use a single rod.

Oct 16, 2019 - 5:47:31 PM

12265 posts since 6/29/2005

quote:
Originally posted by rudy

I only use 1/4"-20 all thread.  I haven't noticed any twisting when tightening, but that might be due to the larger size rod.  I wouldn't use a smaller size, but I use a single rod.


If you are going to use threaded rod, probably 1/4-20 is better.  In terms of a regular rod, a 3/16" steel rod exceeds the tensile strength requirement of tightening a banjo neck by so much it's ridiculous.  Imagine a banjo string that diameter.

My fear with the threaded rods is not tensile strength, but a twisting vulnerability.

Oct 16, 2019 - 8:05:26 PM

6252 posts since 8/28/2013

"My fear with the threaded rods is not tensile strength, but a twisting vulnerability."

I wholeheartedly agree with that sentiment. While I've never done anything with Rudy rods, I have done things with threaded rod that didn't hold up well, and have seen many, many bolts that have twisted and sheared off. Where have all those bolts sheared? Somewhere along the threaded portion.

Oct 17, 2019 - 5:15:40 AM

12265 posts since 6/29/2005

quote:
Originally posted by G Edward Porgie

"My fear with the threaded rods is not tensile strength, but a twisting vulnerability."

I wholeheartedly agree with that sentiment. While I've never done anything with Rudy rods, I have done things with threaded rod that didn't hold up well, and have seen many, many bolts that have twisted and sheared off. Where have all those bolts sheared? Somewhere along the threaded portion.


That's right, and most long bolts only have a portion at the end threaded.

Oct 17, 2019 - 5:33:45 AM
Players Union Member

rudy

USA

14578 posts since 3/27/2004

For those who shop at Menard's, either physical location or on-line:

Midwest Fasteners Cross Dowel Nut

As far as a threaded connector breaking where it's threaded, isn't that rather obvious?  A chain is only as strong as it's weakest link, and a threaded rod (of any size) is going to follow the same laws of physics.  The diameter is reduced at the threaded portion, so why wouldn't it break there?

If anyone snaps a 1/4"-20 threaded rod from excessive force they probably need to review their basic mechanical skills.  If someone is absolutely green at being able to feel then too much is too much it's easy to stick a bolt in a vise and tighten a nut on the threaded portion til it snaps.

If this is a deal breaker for a banjo mechanic I sure don't want to watch as they pull the threads out of the heel by tightening a conventional coordinator rod connection.

This ain't rocket science.  wink

Edited by - rudy on 10/17/2019 05:45:32

Oct 17, 2019 - 6:31:10 AM

2619 posts since 2/18/2009

A 1/4-20 threaded rod has a minor diameter that is within a few hundredths of a 3/16" non-threaded rod. The threaded portions of a 3/16" rod have a minor diameter that is just a little over 1/8", so they're much less beefy.
Zach

Oct 17, 2019 - 7:15:43 AM
Players Union Member

rudy

USA

14578 posts since 3/27/2004

quote:
Originally posted by Zachary Hoyt

A 1/4-20 threaded rod has a minor diameter that is within a few hundredths of a 3/16" non-threaded rod. The threaded portions of a 3/16" rod have a minor diameter that is just a little over 1/8", so they're much less beefy.
Zach


The small amount of "difference" from 3/16" diameter rod to 1/4" diameter rod can be a bit deceptive.  The cross-sectional area is almost doubled when you go from 3/16" to 1/4" diameter.

Oct 17, 2019 - 7:44:44 AM

2619 posts since 2/18/2009

That was what I was trying to point out. A threaded 1/4" rod is about the same as a non-threaded 3/16, so their strengths should be equal, if they are the same alloy. However a Rudy rod has to be threaded at least at the ends, and the minor diameter of a 3/16" threaded portion of a rod is in the .13" range, which is much weaker. A completely non-threaded 3/16" rod would be as strong as a 1/4 fully threaded rod, but with no threads on the ends it wouldn't work, obviously.

Oct 17, 2019 - 8:18:20 AM

6252 posts since 8/28/2013

quote:
Originally posted by rudy

For those who shop at Menard's, either physical location or on-line:

Midwest Fasteners Cross Dowel Nut

As far as a threaded connector breaking where it's threaded, isn't that rather obvious?  A chain is only as strong as it's weakest link, and a threaded rod (of any size) is going to follow the same laws of physics.  The diameter is reduced at the threaded portion, so why wouldn't it break there?

If anyone snaps a 1/4"-20 threaded rod from excessive force they probably need to review their basic mechanical skills.  If someone is absolutely green at being able to feel then too much is too much it's easy to stick a bolt in a vise and tighten a nut on the threaded portion til it snaps.

If this is a deal breaker for a banjo mechanic I sure don't want to watch as they pull the threads out of the heel by tightening a conventional coordinator rod connection.

This ain't rocket science.  wink


No, it ain't rocket science, but it's actually a little more complex than a mere difference in diameter. When threads are cut, heat and other stresses are generated and that can affect the structure and strength of the actual metal. 

Personally, I've never liked commercially available threaded rod. It always seems pretty cheap and soft compared to a good solid rod, although maybe I've just not found a good supplier.

Oct 17, 2019 - 11:35:36 AM

12265 posts since 6/29/2005

I've tried both ways and I can feel the twist when I tighten a Rudy rod that has a threaded rod, but not when it's a solid rod. If one broke in the middle, it would be a real PIA to get it out.  I'd have to cut the wood compression dowel, which in my case is laminated, turned and finished, which takes about 20X more time to do than simply threading the ends of a cold-rolled steel rod (which is cheaper than threaded rod). 

I look at it like this:  Sooner or later some large companies will understand how well Rudy rods work and start installing them on banjos.  When they do that, they will not use threaded rods.

Edited by - Ken LeVan on 10/17/2019 11:36:20

Oct 17, 2019 - 11:47:20 AM
Players Union Member

rudy

USA

14578 posts since 3/27/2004

quote:
Originally posted by Ken LeVan

I've tried both ways and I can feel the twist when I tighten a Rudy rod that has a threaded rod, but not when it's a solid rod. If one broke in the middle, it would be a real PIA to get it out.  I'd have to cut the wood compression dowel, which in my case is laminated, turned and finished, which takes about 20X more time to do than simply threading the ends of a cold-rolled steel rod (which is cheaper than threaded rod). 

I look at it like this:  Sooner or later some large companies will understand how well Rudy rods work and start installing them on banjos.  When they do that, they will not use threaded rods.


Hi Ken,

I'm curious why a rod would be difficult to get out if it did happen to break in the middle.  My rods slip easily through the channeled dowel stick, so I'm sure I'm just misunderstanding your reasoning.

Oct 20, 2019 - 5:31:24 PM

12265 posts since 6/29/2005

quote:
Originally posted by rudy
quote:
Originally posted by Ken LeVan

I've tried both ways and I can feel the twist when I tighten a Rudy rod that has a threaded rod, but not when it's a solid rod. If one broke in the middle, it would be a real PIA to get it out.  I'd have to cut the wood compression dowel, which in my case is laminated, turned and finished, which takes about 20X more time to do than simply threading the ends of a cold-rolled steel rod (which is cheaper than threaded rod). 

I look at it like this:  Sooner or later some large companies will understand how well Rudy rods work and start installing them on banjos.  When they do that, they will not use threaded rods.


Hi Ken,

I'm curious why a rod would be difficult to get out if it did happen to break in the middle.  My rods slip easily through the channeled dowel stick, so I'm sure I'm just misunderstanding your reasoning.

Here is an abbreviated version of my process, leaving a few steps out, but trying to explain why it would be problematic if the rod snapped in the middle.

A threaded anchor is installed in the heel via a hole.


The wooden "Rudy rod" hollow dowel is cut to the correct length, exactly the same length as the ID of the rim and wedged inside the rim from one side to the other.

The steel tension rod goes through the middle of it, the threaded end going into the threaded hole in the anchor, which is in the heel of the neck. 

The wooden dowel must be wedge fitted, straight in, so as not to distort the rim—if it's too short the tension rod will egg the rim when it's tightened.

You tighten it by turning it from the tailpiece side of the rim, so that the threads going into the heel anchor are around 12" from where you are turning it, putting a twisting stress on the rod. (I put in a second bolt or sometimes a second rod, which you see in the picture).

IF for some reason, the rod breaks inside the hollow dowel, you can only withdraw the part of it with the tailpiece lug, the rest remains in the center of the rod, screwed into the anchor through a horizontal bore in the heel, which precludes getting the wooden dowel out and unscrewing the other end of the tension rod without cutting the wooden dowel away to get access to the steel tension rod so it can be backed out with pliers.

Edited by - Ken LeVan on 10/20/2019 17:37:40

Oct 20, 2019 - 5:50:38 PM

12265 posts since 6/29/2005

After writing that whole long treatise, I realize that I could just remove the secondary bolt and pull the neck out the other way and get the broken rod out with pliers— no big deal.

Don't want to break one anyway.

Oct 21, 2019 - 6:12:20 AM
Players Union Member

rudy

USA

14578 posts since 3/27/2004

quote:
Originally posted by Ken LeVan

After writing that whole long treatise, I realize that I could just remove the secondary bolt and pull the neck out the other way and get the broken rod out with pliers— no big deal.

Don't want to break one anyway.


Thanks, Ken.

That was exactly what I was thinking.  A rod that was broken along it's length would pull out with the neck.

When Craig Evans was here shooting video I demonstrated the simplicity of a "Rudy Rod" by cutting 5 strings with diagonal cutters, spinning the acorn nut off the rod, and pulling the neck off the pot in less than 30 seconds.

Oct 21, 2019 - 8:35:09 AM

12265 posts since 6/29/2005

quote:
Originally posted by rudy
quote:
Originally posted by Ken LeVan

After writing that whole long treatise, I realize that I could just remove the secondary bolt and pull the neck out the other way and get the broken rod out with pliers— no big deal.

Don't want to break one anyway.


Thanks, Ken.

That was exactly what I was thinking.  A rod that was broken along it's length would pull out with the neck.

When Craig Evans was here shooting video I demonstrated the simplicity of a "Rudy Rod" by cutting 5 strings with diagonal cutters, spinning the acorn nut off the rod, and pulling the neck off the pot in less than 30 seconds.


I still wouldn't use a threaded rod, but I make a lot of them and don't want some customer to call me and say that their neck has suddenly started to wobble (I would know exactly why). It's like a truss rod—a little bit of time at the front end that prevents time consuming customer service problems later on.

Simplicity, rigidity, and the ability to assemble and disassemble many times during setup is why I use that system.

Oct 22, 2019 - 7:26:32 AM

402 posts since 1/25/2012

Wow--ya'll had a great discussion while I was gone.

And like a bit idiot, I didn't get anything ordered before I left. Looks like I'm going to need to tool up to Menards some time this week and see what they've got in stock.

Oct 29, 2019 - 6:54:39 AM

402 posts since 1/25/2012

I was hoping I could buy online, but the only option I could find was a set of 10 for $12!

I finally made it out to Mendards today--looks they've got 'em for a $1 a pop, in the section with all sliding drawers of hardware. The 1/4-20 threaded rod is a couple aisles over.

I think I got out of there for less than $3 with enough rod and anchors to do two (just in case I pull a Ken and snap the rod! :D )


Oct 29, 2019 - 12:21:50 PM
like this

3612 posts since 5/12/2010

I like this design and have used it on some of my banjos.

I like building with a traditional dowel stick, which is what a lot of people want, but I think they like it mainly for the looks. I still build about half of mine with a traditional dowel stick, but I have to admit my reason for liking it is because it is difficult to get right, and I like showing off.

As Ken shows this attachment method can be made to look just like a traditional dowel stick, and it really is a better design because it is stronger, easier, and more forgiving.

I don't like the look of a nut and L bracket on the tailpiece end like is used on most coordinator rod banjos, so when I use this method I do much the same thing Ken does. I drill and tap a ball tailbolt bracket to fit the rod, and I silver solder this to the rod.

I have used anchors similar to what Ken shows which I made from brass bar stock, and I have also used furniture cross bolt type anchors from the hardware store, whether shop made like Ken's or purchased these provide an advantage if the hole into the heel is bigger than the rod because there is some wiggle room which helps with alignment. I also use a counter sink on the side of the anchor holes facing the pot which helps center the rod into the threaded holes.

I tried threaded inserts for anchors on one, which are very strong the way I do them, but that was not quite as nice to assemble.

One thing I do different when I use this attachment is I insert the anchor from the fretboard side. Not much difference, but the reason I do this is I always use an alignment pin at that location when gluing on the board, and so always have a small hole there which I cover up with an inlay, often a brass star, or an old coin or coal script. So, when I cover up the anchor with something like that, If I ever had to pull that anchor out all I need to do is heat the inlay to remove it, and I could get to the anchor without having to remove a heel cap. I never have had to pull one out, but I worry about the rod getting cross threaded or something.

Oct 29, 2019 - 7:41:14 PM
likes this
Players Union Member

rudy

USA

14578 posts since 3/27/2004

This discussion is interesting in that it points out how a simple attachment system such as the "Rudy Rod" can be easily adapted to whatever the builder wants to incorporate.

I also add the cross dowel nut from the fret board side, but I often use Dobson heels so it works out well for me.  I add a small bit to Titebond in the drilled hole, drop the cross dowel bolt in, and align and lock it into the correct location by snugging a furniture bolt through the heel hole til the glue has dried.  The fret board is added after the cross dowel nut is installed, so there's no visible evidence of its existence.

I've always encouraged new builders to use the system because it makes fitting the heel so much easier.  If the heel profile needs to be shaped slightly for proper alignment then the threaded rod is simply removed so there's full access to the heel.

You can also make a neck adjustable by simply elongating the rim slot; the end nut is loosened and the heel shifted up or down to adjust string height over the upper frets.

The channeled dowel stick can be made in lots of configurations, too.  Round, rectangular, tapered, inlaid, you name it.

Once someone understands how the system works then it opens the floodgates of possibilities and removes all of the physical constraints of previous designs that were less than optimal.

Oct 29, 2019 - 8:02:36 PM

402 posts since 1/25/2012

That's all the reasons I chose it--it bypasses so much of the dowel rod heartache!

One quick question: how much bigger than the threaded rod do you make the hole in the neck that the rod goes through? It seems like a little bit of slop won't hurt, but could end up helping, assuming you need to make some angle adjustments.

Oct 30, 2019 - 1:37:34 PM

12265 posts since 6/29/2005

quote:
Originally posted by crazybilly

That's all the reasons I chose it--it bypasses so much of the dowel rod heartache!

One quick question: how much bigger than the threaded rod do you make the hole in the neck that the rod goes through? It seems like a little bit of slop won't hurt, but could end up helping, assuming you need to make some angle adjustments.


I use 3/16" rods for the tension rod and make the holes in the heel 1/4", which allows for the "schnooly" you are talking about. 

Also, I make the mortise for the anchor rectangular, wider in the neck length axis than in the neck width axis so the anchor can rock back-and-forth a little bit in the event I adjust the heel angle during setup— I don't want to stress the threaded part of the rod by forcing it into a bend under tension.

Everything has a little leeway so you can get the position right, and it all tightens up when you tension the rod(s).

Edited by - Ken LeVan on 10/30/2019 13:38:28

Oct 30, 2019 - 4:10:07 PM
Players Union Member

rudy

USA

14578 posts since 3/27/2004

quote:
Originally posted by crazybilly

That's all the reasons I chose it--it bypasses so much of the dowel rod heartache!

One quick question: how much bigger than the threaded rod do you make the hole in the neck that the rod goes through? It seems like a little bit of slop won't hurt, but could end up helping, assuming you need to make some angle adjustments.


I drill the neck heel 9/32" for the 1/4" all thread rod.  As stated previously, I add a bit of Titebond and align with a furniture bolt.  This ensures that there are no alignment problems later.

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