Replies

1. 
   Len | May 21, 2003 07:35am | #1

   Hi forestgirl,

   There are several types of basic tips. Regular, a straight shaft with a crowned end; roller, a little wheel; flat; tapered, comes to a round point,; button, large crowned end; and wide, flat button.

   It really just depends on what your trying to measure. But for most measurements, you don't need anything more than the regular tip. Here are some examples of  what I have occasionally used other tips for. The roller is nice if your trying to follow a curve or determine out of round. Tapered is for tight spaces, inside a grove or into a hole. I haven't had a whole lot of use for the other tips. I don't see the machinists at work using much more than the basic tip most of the time either.

   Sounds like you went on a little shopping spree. I just went to a antique tool swap meet and got a jig saw that was made in the early 20's for $10. Along with some nice dividers and calipers. Nothing over $10. Great fun.

   Len

2. 
   jackiechan | May 21, 2003 07:41am | #2

   Forest Girl,

   The different tips for the dial indicator are for different surfaces being measured.  E.g. a wide flat bottom tip may be used for checking the blade height on a jointer, whereas a sharp cone tip couldn't get any sort of purchase on the blade's edge.  The sharp cone tip might be used for the large flat surface of a circular saw blade (RAS, TS, etc...).  A round bullet tip tends to be the standard tip that the indicators are supplied with.  Some tips are available in extra long lengths to make sometimes difficult measurements - as in checking the arbor run out on a table saw.

   Dan Kornfeld, Owner/President - Odyssey Wood Design, Inc.

1. 
   forestgirl | May 21, 2003 08:41am | #4

   Hmmmmm, you've all done so well with that one, maybe you can translate this chart that's on the back of the digital calipers, or at least give me some hints!View Image

   forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl   ;-)

1. 
   BenM | May 21, 2003 02:22pm | #5

   It looks like specs for two types of machine screws, ISO and Whitworth.  The first column is the screw diameter measured at the threads and the third column is the screw diameter measured at the root (threads excluded). The second column is the pitch or distance between threads measured along the length of the screw.  The last column could be the drill diameter recommended for that size screw when predrilling.

1. 
   forestgirl | May 21, 2003 05:40pm | #7

   Thank you, thank you.  Not sure I'll be using the chart every day <grin> but who knows?  Never heard of Whitworth screws.  Learn something every day.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl   ;-)

1. 
   outside | May 21, 2003 09:49pm | #8

   Forestgirl,

   Rush out an buy yourself an MG TD to restore. All Whitworth threads. Whitworth threads are supposedly stronger than UN threads. Whitworth threads and Lucas electrical systems were partially responsible for old MG's having reputation for being "difficult".

   Scott

2. 
   forestgirl | May 21, 2003 10:07pm | #11

   There's an old Triumph chassis in our garage extension, does that count? <g>  forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl   ;-)

3. 
   Andrew | May 21, 2003 09:50pm | #9

   Now this is my machinist side talking, and this probably won't make a difference in a woodshop, however, I'll say it anyways. I've got 2 digital calipers, one cheap import, and another very nice 8" mitutoyo, and surprisingly when I checked their accuracy with a set of gage blocks, the cheap ones were within .0005" over 6". Repeatability can be a problem, so every now and then I close the calipers, zero them, then open and close them several times, checking to make sure they aren't giving false readings. If your calipers don't give consistent readings then they're pretty much useless.

   The biggest problem with having calipers in a woodshop is the dust which can throw off the accuracy, and if it gets into the circuits, it will destroy them, so keep them out of the dust when they're not being used. When it comes time to measure something important, like a bearing or a shaft, dust that sticks to the faces can throw the measurements off several thousandths, so what I always do is run my finder over the jaws to clean them, then close and zero them. It also helps to wiggle them around a bit on the object being measured to make sure your getting an accurate reading.

   With dial indicators there are a couple of things to watch out for. First of all, the cheap magnetic bases that have a hinged arm for making fine adjustments are junk. I find that if you even look at that hinge the wrong way it moves, and then you have to reset the dial. Secondly, make sure that the bezel turns smoothly or when you try and zero the dial the whole thing moves with you. Third, I'm sure you're aware of parallax errors, and it's no different for dial indicators. For accurate measurements, try to keep the indicator perpendicular to the surface being measured. Lastly, and you probably know this already, but when your measuring runout, just touch the tip to the work, then press the indicator down a bit more and zero it so you can see both positive and negative movement. Other wise the tip might only be touching the highest spot, and not contact anywhere else, making it look like there is no runnout when there really is.

   Well, that was long. Hopefully you might find some of this useful.

   Andrew

4. 
   forestgirl | May 21, 2003 10:06pm | #10

   That was all helpful Andrew.  I know nothing about dial indicators!

   I did measure a quarter several times to see if I'd get the same reading, and did thankfully.  I figure if that's the case, the calipers will work fine for the type of work I'm doing.  They provide a little "hatch" that can be removed to clean the inside with compressed air.  I'll keep it in the provided case except when using. 

   Thanks again for the info.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl   ;-)

3. 
   mrles | May 21, 2003 07:52am | #3

   Jamie

   The dial indicator has different tips so you can configure it to the needed application. The magnetic base needs to be on a flat surface and then you need a tip that will reach the point you want to check. On your table saw you wouldn't want the base on the miter slot or hanging over the blade hole so you set it out and reach in with a long tip. I've seen machinist use jointed tips and go up and over and back down to get a reading. That's one toy I haven't bought yet.

   I went in to see the Astros and the Marlins at Minute Maid Stadium with one of my daughters a couple of weeks ago, we got a free Astros cap. The cap was the best part of the game. The Marlins are a little weak but the Astros didn't play much better, they are playing better now. Minute Maid is a beautiful stadium I sure hope we have a good year.

   Gods Peace

   les   

4. 
   cutoffcollector | May 21, 2003 05:07pm | #6

   I've used a dial caliper for several years now and would be lost without it. However, for a year or two, I was unaware of one of the functions it offers. The the end of the extendable jaw and the back of the main frame can also be used for measurements. You can set a dimension, lock the extendable, then rest the extendable on the surface to be marked to the point where the back of the main frame is square with the surface, then make your mark at the far end of the extendable jaw.

   It's a whole lot easier than trying to mark a dimension with a ruler or tape, of course you're limited to 6 inches max.

   Jon