Super Fast Indicating [Archive] - The Home Shop Machinist & Machinist's Workshop Magazine's BBS
The Home Shop Machinist & Machinist's Workshop Magazine's BBS > General > Super Fast Indicating
View Full Version : Super Fast Indicating
http://www.youtube.com/watch?feature=player_detailpage&v=tn7A9PqNftY
Hmm- seems to me the ball bearing 'trick' was for part alignment. For indicating, he actually used an indicator :)
I guess I should have titled the thread "Super Fast Alignment". ;)
Darn!. "Super Fast Truing" then. :D
I think Frank Ford has building one of these on his site.Here it is: http://www.frets.com/HomeShopTech/Tooling/CenteringRoller/centeringroller.html
Here it is: http://www.frets.com/HomeShopTech/Tooling/CenteringRoller/centeringroller.html
Yes, this design is ...uh ... a bit more elegant. ;)
http://i966.photobucket.com/albums/ae148/MPdisp/Truingtoolforlathework.jpg
http://i966.photobucket.com/albums/ae148/MPdisp/Truingtoolforlathework-closeup.jpg
The front face is gravy. It's hanging right out there for anyone to get at with a dial indicator or a roller tool. What if you just turned the piece around to machine the opposite end and you need to dial the face now masked by the jaws so it's parallel to the plane of rotation?
Now if some clever dude would figger a quick way to dial in the BACK side... Parallels and jaw stops are seldom reliable closer than 0.002" because the jaws spring out a little as you tighten the chuck.
I've never found a better way than mounting the DTI on the tool post, dancing it in and out of the jaws by cranking the cross slide to dial in the back side of the work. PITA but when you're done you know where the work references are in relation to the spindle axis. Gotta be a quicker way that's as accurate and reliable.
I can see a potential problem with using this technique for cylindrical alignment. If you ran the bearing in even a bit to far, it could walk the part out of the chuck.
You're describing an arrangement similar to the push type knurling tool, right?
Yes, the part could walk out of the chuck. You just have to realize that some setups are 'iffy', and pay attention. If you get a feeling that something isn't going to be held sufficiently, you should try to think of ways to help that. One way is to put a rod in a tailstock chuck and use that to prevent a workpiece from moving towards the right- and out of the chuck. You might call that an extended center. It should be pointed and fit a recess in the workpiece, same as a center, although it may or may not be used to actually center the workpiece.
I've used that method in several ways- one of them was to drill a very small diameter hole in the end of the workpiece, and the same in the rod coming from the tailstock. Then insert a short length of music wire or similar- this can work if you need some control, but also need the room for the tooling setup.
This type of thing is also good when parting off washers or the like. Having a rod inserted into the end of the workpiece gives something to catch the pieces as they are parted off. In this case the rod or wire is not used to support the workpiece- it's just a convenience.
I've had an idea in mind for some time now for a steady rest of another kind- one that doesn't mount on the ways or the carriage, but instead mounts on a bar that is bracketed onto the back of the headstock and has another rigid support at the tail end of the bed. Alternatively, it could also be affixed to a bracket mounted on the back of the tailstock. The brackets and the bar are made to be parallel to the spindle axis, and the guide bearing assembly rides the bar for position behind the workpiece. The guides may not be the ultimate in rigidity mounted this way, but it has to be much better than nothing when you're dealing with long pieces, and need the carriage to have unrestricted travel along the bed.
Depending on your level of ingenuity, the bar could double as part of a taper turning aid, and it could also hold a profile pattern that a pivoting tool holder could follow. The bar could also be the attachment point for a dial indicator, or any other secondary motorized accessory such as a grinder.
I'm using the word 'bar', but it would actually be a rigid guideway of some type, so whatever would work for you-
Seems I've digressed a bit- one of the uses I was looking at for the bar was to hold the bearing assembly that would be used in the same manner as shown in the video to align a workpiece. Some means of adjusting the radial position would have to be included in this accessory.
Super Fast Indicating [Archive] - The Home Shop Machinist & Machinist's Workshop Magazine's BBS
The Home Shop Machinist & Machinist's Workshop Magazine's BBS > General > Super Fast Indicating
View Full Version : Super Fast Indicating
http://www.youtube.com/watch?feature=player_detailpage&v=tn7A9PqNftY
Hmm- seems to me the ball bearing 'trick' was for part alignment. For indicating, he actually used an indicator :)
I guess I should have titled the thread "Super Fast Alignment". ;)
Darn!. "Super Fast Truing" then. :D
I think Frank Ford has building one of these on his site.Here it is: http://www.frets.com/HomeShopTech/Tooling/CenteringRoller/centeringroller.html
Here it is: http://www.frets.com/HomeShopTech/Tooling/CenteringRoller/centeringroller.html
Yes, this design is ...uh ... a bit more elegant. ;)
http://i966.photobucket.com/albums/ae148/MPdisp/Truingtoolforlathework.jpg
http://i966.photobucket.com/albums/ae148/MPdisp/Truingtoolforlathework-closeup.jpg
The front face is gravy. It's hanging right out there for anyone to get at with a dial indicator or a roller tool. What if you just turned the piece around to machine the opposite end and you need to dial the face now masked by the jaws so it's parallel to the plane of rotation?
Now if some clever dude would figger a quick way to dial in the BACK side... Parallels and jaw stops are seldom reliable closer than 0.002" because the jaws spring out a little as you tighten the chuck.
I've never found a better way than mounting the DTI on the tool post, dancing it in and out of the jaws by cranking the cross slide to dial in the back side of the work. PITA but when you're done you know where the work references are in relation to the spindle axis. Gotta be a quicker way that's as accurate and reliable.
I can see a potential problem with using this technique for cylindrical alignment. If you ran the bearing in even a bit to far, it could walk the part out of the chuck.
You're describing an arrangement similar to the push type knurling tool, right?
Yes, the part could walk out of the chuck. You just have to realize that some setups are 'iffy', and pay attention. If you get a feeling that something isn't going to be held sufficiently, you should try to think of ways to help that. One way is to put a rod
 in a tailstock chuck and use that to prevent a workpiece from moving towards the right- and out of the chuck. You might call that an extended center. It should be pointed and fit a recess in the workpiece, same as a center, although it may or may not be used to actually center the workpiece.
I've used that method in several ways- one of them was to drill a very small diameter hole in the end of the workpiece, and the same in the rod coming from the tailstock. Then insert a short length of music wire or similar- this can work if you need some control, but also need the room for the tooling setup.
This type of thing is also good when parting off washers or the like. Having a rod inserted into the end of the workpiece gives something to catch the pieces as they are parted off. In this case the rod or wire is not used to support the workpiece- it's just a convenience.
I've had an idea in mind for some time now for a steady rest of another kind- one that doesn't mount on the ways or the carriage, but instead mounts on a bar that is bracketed onto the back of the headstock and has another rigid support at the tail end of the bed. Alternatively, it could also be affixed to a bracket mounted on the back of the tailstock. The brackets and the bar are made to be parallel to the spindle axis, and the guide bearing assembly rides the bar for position behind the workpiece. The guides may not be the ultimate in rigidity mounted this way, but it has to be much better than nothing when you're dealing with long pieces, and need the carriage to have unrestricted travel along the bed.
Depending on your level of ingenuity, the bar could double as part of a taper turning aid, and it could also hold a profile pattern that a pivoting tool holder could follow. The bar could also be the attachment point for a dial indicator, or any other secondary motorized accessory such as a grinder.
I'm using the word 'bar', but it would actually be a rigid guideway of some type, so whatever would work for you-
Seems I've digressed a bit- one of the uses I was looking at for the bar was to hold the bearing assembly that would be used in the same manner as shown in the video to align a workpiece. Some means of adjusting the radial position would have to be included in this accessory.