# Adapting digital calipers



## bobmac0825 (Feb 13, 2009)

Hi there,
I would like to adapt my digital calipers as a router bit height gauge on my router table. I have a few ideas but nothing definite so has anybody done this and could you indicate how you did it, please?
Thank you,
Bob.


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## harrysin (Jan 15, 2007)

Bob, woodwork doesn't require accuracy of a few thousandths of an inch.there is movement with the weather. I therefore have never used any of my digital callipers or precision height gauge. Marking a line on a scrap of wood and setting the cutter to the line is just one of many simple methods. The marketplace is full of very low cost simple height gauges.


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## Duane867 (Oct 25, 2008)

I just use a steel rule my self. But you can make a height gauge pretty easily.
As far as adapting your calipers goes, that completely depends on the type you have.
Does your set have a depth gauge that protrudes out the bottom when in use ? 
If so then thats an easy way to check height as well. Just make a small u shaped jig to hold the calipers and zero out the calipers on the plate beside the bit. Then slide the jig over and record your bit height.


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## crquack (Oct 10, 2008)

There is a huge and useful thread on this in the Table routing section.

Two problems (apart from those already metnioned by others) with using a digital caliper/gauge to set the router bit height:

1) Trying to set the digits to an exact figure manually is maddening.
2) I have found that the digital calipers (at least my cheap ones) become unreliable if the workshop temperature drops to 10 degC.


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## Ghidrah (Oct 21, 2008)

The new router lifts solve that problem, before I bought the BD I used the brass bars for most of the new work, however when duplicating existing stock hgt adjustments was tedious at best.

With new work you are the god, with restoration OY!


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## Duane867 (Oct 25, 2008)

After taking a look at mine and thinking it through a little better if you have the type that has the depth gauge or not the same way of mounting them will work. Simply zero it out extended flush with the table. When the calipers are pushed closed the increments will display just as they would using it to gauge thickness. From where you zeroed it to maximum height. You could also ( if you have the plastic digital calipers that is ) super glue a small square piece of acrylic to the bottom of the sliding section to use it more accurately on bits wider then the calipers slide. Just use your square to square it up when gluing. You would have to dedicate that pair for bit / blade height only after that but at $9.99 a pair from Harbor Freight you can afford to  

I think I'm going to do this myself this week some time actually. 
Thanks for making me think it through more ! 


I have a cheap pair from Harbor Freight, left them in the trunk in 20 degree weather, as well as 90 degree weather and used them the same days. Never noticed any inaccuracies. 
The pair from Harbor Freight is also not to bad to dial in exactly repeatedly. I am sure they very though from pair to pair.


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## Mike Wingate (Apr 26, 2009)

I have made a simple one by adapting a cheap digital vernier gauge, and holding it in a plastic block. There should be a picture of it on this forum. I find it very useful. Note the exact height and you can later return and make another cut/item/project. Its use outweights any negative criticism.


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## bobj3 (Jan 17, 2006)

Just my 2 cents 

" adapting a cheap digital vernier gauge " a bit over kill and not worth the time to make one..you can blow on it and will not be on the button 

Wood and Metal are not the same..now if you had a mill it would be worth the time but for a router table, it's over kill..

=========


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## Mike Wingate (Apr 26, 2009)

A couple of images of my device. I cut off one of the caliper arms. It has a zero reset functionwhich is handy. Built for less than £9.


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## dustmaker (May 18, 2009)

An interesting thread. I have used a digital caliper for height adjustments for a while, mostly because my old eyes can't see increments of 1/32 or less on rulers and such. But I have found a much easier method that is very accurate. A little known fact, but the human finger can detect very small variations, on the order of 1/1000 of an inch. Just raise your router plate 1/1000" and slide your index finger across with your eyes closed (router off, of course!). Most people can detect the edge. So with that knowledge, all that is really needed are blocks of the needed heights. There are the brass bars that many use, but I cut my own measurement blocks out of MDF. I haven't lost a bit of accuracy in my work, but set up tends to go much quicker since I put the digital tools away. Not that these tools are wrong, just not as efficient for me. YMMV.


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## Duane867 (Oct 25, 2008)

I'd agree with that Frank 

I just like things that go beep, and shine to much though


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## BigJimAK (Mar 13, 2009)

BJ.. But how else can you tell you cut it 3" too short, to 3 decimal places? :jester:




bobj3 said:


> Just my 2 cents
> 
> " adapting a cheap digital vernier gauge " a bit over kill and not worth the time to make one..you can blow on it and will not be on the button
> 
> ...


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## bobj3 (Jan 17, 2006)

HI Jim

I use my rubber ruler most of the time  just a little pull and it just right 

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BigJimAK said:


> BJ.. But how else can you tell you cut it 3" too short, to 3 decimal places? :jester:


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## Duane867 (Oct 25, 2008)

You laugh now sir but use a digital caliper set on a box joint or dovetail joint and look at perfect and repeatable results you'll get


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## Ghidrah (Oct 21, 2008)

Duane867,
What method do you use to elevate your bit? If it isn't a threaded lift how do you manage quick and accurate .001 setting changes? 

Most current lifts are marked for .007 to .003 and do it fast. I know mechanical lifts can be cost prohibitive for many when not used for business purposes. 

My guess is that lifts were developed to assist small business contractors with reproduction/restoration projects just like contractor grade molders. Local mills and wood smiths charge an arm and leg to reproduce molding, (which is why I bought my molder yrs ago and eventually the lift).


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## Duane867 (Oct 25, 2008)

The calipers I use are not machinist calipers. They do not read in .000. they read in .00 so it makes things a LOT easier for me when using for wood working. Most cheap digital calipers only read in .00 though. My lift is the factory screw advance that came on my Ryobi. I can get it with in .02 easily if I bump it up slowly. I use a T-handle above table though also. That makes a world of difference in how accurately you have control over height adjustments IMHO.


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## Mike Wingate (Apr 26, 2009)

Each to their own. If people want to be ultra accurate with repeatable setups. e.g. Lock Mitre bits with different thicknesses of wood, I can see that a digital vernier height gauge makes sense. If other methods are used and keep people happy, great. This site shows the diversity of ideas and methods. If it works, it works.


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## Duane867 (Oct 25, 2008)

Absolutely.


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## scoly (Mar 13, 2009)




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## Mike Wingate (Apr 26, 2009)

Nice idea. Why not fit a plastic/wood pad, that touches the tip of the router bit. I presume you zero to the table top, then touch the top of the bit ?


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## bobj3 (Jan 17, 2006)

I will 2nd.Mike's post 

But I use the items below,very quick and you can stack them up to 2 " tall and they only cost peanuts and will not damage the bits 
The KISS way I think..
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## Hamlin (Dec 25, 2005)

I guess I'm missing the point here. Brass setup bars are more accurate than anything else. There are aluminum depth gauges on the market as well. A good set of brass setup bars, the good ol' reliable rubber rule and a self centering pencil is all one truly needs. K.I.S.S. 

If you're after what appears to be "super precision"... then woodworking isn't that. Why? Wood moves!! Metal will do the same thing with temperature changes even if only slightly. But, it too changes.


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