Page 1 of 1

Looking for ultra low tension plunger dial indicator

Posted: Mon Apr 05, 2021 5:24 pm
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!

Re: Looking for ultra low tension plunger dial ndicator

Posted: Mon Apr 05, 2021 9:55 pm
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.

Re: Looking for ultra low tension plunger dial ndicator

Posted: Tue Apr 06, 2021 12:25 am
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...

Re: Looking for ultra low tension plunger dial ndicator

Posted: Thu Apr 08, 2021 7:22 pm
by Mike Conklin
Certainly someone must use the SM version? Is there a brand on the indicator?

Re: Looking for ultra low tension plunger dial ndicator

Posted: Thu Apr 08, 2021 9:32 pm
by Barry Daniels
Stew-Mac does sell an new digital indicator, for this jig, separately.

https://www.stewmac.com/luthier-tools-a ... gauge.html

Re: Looking for ultra low tension plunger dial indicator

Posted: Sat Apr 10, 2021 9:30 am
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.

Re: Looking for ultra low tension plunger dial indicator

Posted: Sat Apr 10, 2021 11:10 am
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.

Re: Looking for ultra low tension plunger dial indicator

Posted: Fri Apr 16, 2021 3:10 pm
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.

Re: Looking for ultra low tension plunger dial indicator

Posted: Fri Apr 16, 2021 3:23 pm
by Mike Conklin
Thank you Tom! I will check it out.

Re: Looking for ultra low tension plunger dial indicator

Posted: Fri Apr 16, 2021 3:25 pm
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".