FILENAMES: gage1.gif gage2.gif DESCRIPTION: This is a drawing of a gage for checking the height of the cutting tool on a lathe. Thanks to AL . AL provided the following description: >A GAGE for finding tool center on the Lathe. >See drawing gage1.gif. >Construction of the center gage. >The gage is made of two pieces >a .5 X 2.125 X 2 inch piece of material, >and a bubble glass. >The material can be anything that will withstand heat and abrasion >(aluminum) >The bubble glass can be found at any good hardware store. >I bought replacement vials for a stanley level.(2 fer 5 bucks) > >There are only a couple dimensions that are real important. >The step on the back side is the centerline >The 5/16ths hole needs to be parrallel to the centerline. >The V needs to meet at the centerline. >The angle DOES NOT have to be 120 degrees included, >it should be more than 90, otherwise it is hard to locate it against >the workpiece. >slip the vial in the 5/16ths hole and epoxy in place. >The vial has a slight bend to it the high point should have a couple >lines painted on it.this side toward the .25 slot cut in the top. > >To use the gage place the V side against the workpiece. >Rotate until the bubble shows that the gage is parallel to the ways. >The toolpoint should touch the bottom of the step milled in the back. --------------------------------------------------------------- SINCE THIS FILE WAS FIRST POSTED, THE FOLLOWING DISCUSSION HAS OCCURED IN THE rec.crafts.metalworking NEWSGROUP. --------------------------------------------------------------- Chris Kantarjiev wrote: > Oh ... is this good enough? I set up the block in the vise with the bevel > protractor (I don't have angle blocks) find a decent Z value, lock the quill, > set zero on the knee, and hack away one side. Then I reverse it in the vise, > and cut to the same Z value without disturbing the zero set or the quill? OOPS!! good question your idea was a workable way. the protractor is a good idea. if you scribe a line to show the centeline. and cut to the line you can control the depth easily. I am going to modify the drawing so that if you set the corners of the step on a parallel in the vice you can cut the first side of the angle then useing a square block you can set the same corners parallel to the top of the jaws and then cut the second angle.I think this would make it easier. this would make the 2.125 dim a little longer. AL --------------------------------------------------------------- I'm planning to make GAGE1 over the long weekend; the only thing that isn't obvious to me is how to get the V notch properly centered. I mean, I get the basics - set it up at 30 degrees in the vise and go for it - but the thing I'm not certain of is how to do the setup so I get the point of the notch exactly on the center line. I see two problems, on easy, one harder. The basic task is to cut the hypotenuse of the triangle - I can compute the length of that hypotenuse. So I need to start exactly at the corner, in both x and z axes. X is easy with and edge finder; I'm not sure how to do z - in particular, I don't know how to do it repeatably, and it has to be the same on both sides. Oh ... is this good enough? I set up the block in the vise with the bevel protractor (I don't have angle blocks) find a decent Z value, lock the quill, set zero on the knee, and hack away one side. Then I reverse it in the vise, and cut to the same Z value without disturbing the zero set or the quill? --------------------------------------------------------------- I am going to modify the drawing so that if you set the corners of the step on a parallel in the vice you can cut the first side of the angle then useing a square block you can set the same corners parallel to the top of the jaws and then cut the second angle. You must mean perpendicular to the top of the jaws for the second part? This is a neat trick, using the dimensions of the step to set up similar triangles for the notch... if you scribe a line to show the centeline. and cut to the line you can control the depth easily. Um, cut to the line by eye? Seems like it's not very accurate.... --------------------------------------------------------------- The accuracy of a layout line is very good can be eyeballed within .005/.01 If you can get rid of other factors that cause inaccuracy. I have uploaded the following file to the drop box. http://www.metalworking.com/dropbox/GAGE2.GIF If you look at Item 1 you can see that I have Distorted the angle by 5 degrees this is an extremely large error, which caused the centerline to move .043 this would make the tool of very low quality(useless). With a protractor you should be able to able to keep the error within 1 degree. which would make the tool work quite well, .01/.015 above or below center is not going to make any difference on a manual lathe. (on a cnc it would be important) to get away from the problem you can Dial In the angle at points 1 and 2 or you can cut the step as shown in this drawing and it will do the indexing for you. If you don't mind I would like to add these comments and your comments to the text file when I update it. I think this would make it easier for people to understand the project. AL ---------------------------------------------------------------