Looking for ultra low tension plunger dial indicator

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Mike Conklin
Posts: 18
Joined: Tue Mar 16, 2021 1:57 am

Looking for ultra low tension plunger dial indicator

Post by Mike Conklin »

Hello,

When a certain company came out with a string hight indicator, (which they now suggest is only for nut slotting...it's also great for measuring string height at any fret) I found it intriguting and ended up making my own for about 20 bucks. Brass, dial and all. I've used it to great effect for years. Unfortunately, the dial indicator is on its last legs so I've been look for a replacement. The specs for the indicator are 0 -.25" in 1000ths increments.

The problem? The plunger tension (or throw) is very feather light on this particular indicator. I have purchased at lease 6 replacements trying to replicate it. However, the throw is just too stiff and I've I've returned them all. The contact point on the plunger should NOT be depressing the string. It should be so light that the string doesn't even know it's sitting on top. This is the only way to gauge an accurate measurement.

I cannot recall where I purchased this "Aerospace" brand of indicator. The tension was perfect but, unfortunately, the product was otherwise junk prone to sticking, the actual dial pointer falling off(!) and etc.

Has anyone else made this instrument? If so are you happy with the throw and, if so, where may I please obtain one?

Else, another possible solution, is there a way and has anyone had experience in loosening the tension on the plunger spring?

This is what I thought was a simple problem but now I'm a couple months into it.

Pix attached.

Thanks in advance!
Attachments
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Last edited by Jim McConkey on Fri Apr 09, 2021 1:45 am, edited 1 time in total.
Reason: Fixed spelling in title.

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Barry Daniels
Posts: 2777
Joined: Thu Jan 05, 2012 10:58 am
Location: The Woodlands, Texas

Re: Looking for ultra low tension plunger dial ndicator

Post by Barry Daniels »

I am not aware of low pressure indicators, but if I had 6 indicators standing around, I would sacrifice one and take it apart to see if I could unwind or stretch the spring and lesson the tension. It might work.
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Mike Conklin
Posts: 18
Joined: Tue Mar 16, 2021 1:57 am

Re: Looking for ultra low tension plunger dial ndicator

Post by Mike Conklin »

I returned all of them but the thought did occur to me. After all, I am a luthier so I can't just keep buying and collecting until the right one comes along. Which reminds me of an old joke one of luthier friends was fond of: Whats; the difference between a luthier and a cheese pizza? Anyone? I can't be the only guy who knows the answer...

Mike Conklin
Posts: 18
Joined: Tue Mar 16, 2021 1:57 am

Re: Looking for ultra low tension plunger dial ndicator

Post by Mike Conklin »

Certainly someone must use the SM version? Is there a brand on the indicator?

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Barry Daniels
Posts: 2777
Joined: Thu Jan 05, 2012 10:58 am
Location: The Woodlands, Texas

Re: Looking for ultra low tension plunger dial ndicator

Post by Barry Daniels »

Stew-Mac does sell an new digital indicator, for this jig, separately.

https://www.stewmac.com/luthier-tools-a ... gauge.html
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Tom Snape
Posts: 24
Joined: Sat Feb 11, 2012 5:51 pm

Re: Looking for ultra low tension plunger dial indicator

Post by Tom Snape »

I recently purchased a string height indicator which uses a digital readout. The only pressure on the string is the mass of the plunger which is very light. I use it on nylon ukulele strings and I think it works great. I bought it from G-Tech guitar works, but I see LMI has something that looks similar.

Brian Evans
Posts: 921
Joined: Sat Aug 30, 2014 8:26 am
Location: Tatamagouche, Nova Scotia

Re: Looking for ultra low tension plunger dial indicator

Post by Brian Evans »

The spring tension on long stroke (1" stroke) dial indicators is probably higher than the tension on 1/4" stroke versions. Have the other DI's all been 1/4" stroke? They aren't very common.

Mike Conklin
Posts: 18
Joined: Tue Mar 16, 2021 1:57 am

Re: Looking for ultra low tension plunger dial indicator

Post by Mike Conklin »

Brian, I've tried long plungers but kind if surmised that the shorter shaft is going to have less tension. I have another of the version I'm having trouble with and I think I'll be doing some surgery to see whats what inside. I've been in them before. looks like the inside of a watch. But, it's dead anyway so, no harm no foul.
Last edited by Mike Conklin on Fri Apr 16, 2021 3:24 pm, edited 1 time in total.

Mike Conklin
Posts: 18
Joined: Tue Mar 16, 2021 1:57 am

Re: Looking for ultra low tension plunger dial indicator

Post by Mike Conklin »

Thank you Tom! I will check it out.

Mike Conklin
Posts: 18
Joined: Tue Mar 16, 2021 1:57 am

Re: Looking for ultra low tension plunger dial indicator

Post by Mike Conklin »

Thanks Barry! I did not notice that before. Of course, SM charges twice of what something is worth (or more) but it's good to know there is a solution if all else fails. I mean really. $45 for the indicator and ANOTHER $45 if you want the inch cube of brass that you could grind and drill out in 15 minutes for about $5???? Jeeze. I guess their mission statement is "There's a sucker born every minute".

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