Tool for Indicating Parts in the Lathe Quickly

[raynerd]

I was browsing youtube some weeks ago and came across the video posted below about a simple tool that can be used to indicate parts quickly on the lathe. Still very much learning and trying to find my feet in model engineering, I often remove parts from the chuck only realising they needed to stay in the for next job or understanding that if I had planned a little better, the job could have stayed in the chuck for multiple steps.



The tool is very simply a bearing mounted on some sort of arbour. In my case it is a piece of steel bar
and the bearing bolted to the end. The chap in the video has welded the bearing in place and this is actually better. The problem I have with my bolting method is that the bolt pertrudes and can interfere with what your trying to true up in the chuck. That said, it hasn`t been a problem yet but can see that I`ll get in a situation where I can`t use it because of the nut at some point.



The tool is setup on the tool post so that the bearing is held parallel to the jaws. The work is lightly clamped in the jaws and the bearing moved towards the work piece until the bearing spinds consistantly.

The video shows much better than I can explain but I have to say that this has been working 100% for me and has made this job much quicker.

[Lew_Merrick_PE]

The tool is very simply a bearing mounted on some sort of arbour. In my case it is a piece of steel bar and the bearing bolted to the end. The chap in the video has welded the bearing in place and this is actually better. The problem I have with my bolting method is that the bolt pertrudes and can interfere with what your trying to true up in the chuck. That said, it hasn`t been a problem yet but can see that I`ll get in a situation where I can`t use it because of the nut at some point.

One of my favorite tricks when needing a low-profile attachment for a bore is to turn my stub flush with the end of the bore, drill & tap for an appropriately small pipe plug, slit the stub radially 2-3 places (drilling a "stop hole" as appropriate), and using the pipe plug to expand the stub to retain the element.  Your stub has to be larger than ø.375 as a 1/16 NPT plug is ø5/16 at it's large end.  When I am tapping for the plug, I try to leave 3-5 threads proud at "hand tight" so I still have a bit of expansion and a nearly flush face when tightened.  It does not take that much expansion to make for an extremely strong retention.

[jim]

this looks to be one of them tools that will be used a lot!!!!

i'll be digging out a bearing and making one of these this weekend!!

thank you!!

[raynerd]

Jim, glad you like the idea, I thought it was good when I saw the video on youtube. I`ve used my loads since making it and it only took me minutes to knock together. I would like to make another more like the one in the video, welded and on an extended arm as it looks a little easier to get in position. That said, mine does the trick just fine!

[Mustang]

Here's a different approach to the tool that you made. http://s255.photobucket.com/albums/hh128/Andy_BB/.

I originally saw this on Frank Ford's site and had to make it. I agree that it's a very useful tool that sees a lot of use in my shop.

Andy

[crankshafter]

Hey hey hey
Been using this tool for a long time.
Why use hex.bolts/ nuts, not to mention welding on a bearing  make it simple, use a drop of Loctite. Figure?
Best R.
CS

[raynerd]

Nice work! - Yep, loctite would be a good call or a similar bolted design as Mustang has shown. The problem is again with the bolt, you can`t get right in up against the chuck for small work right?

[75Plus]

Seems like a good application for a flat head, socket head, screw.

Joe

[jim]

well, i made one of these this morning, so simple!!

i just used some 1/2" square bar, turned one end to fit a bearing and simply made it a press fit (so nothing is proud of the bearing).

just had a go with it on 1 1/2" dia disc, .080" wide, got it to run better than .0005" in no time at all!!

NOTE, if anyone is going to make one, i'd make one with a bearing on both ends, it could then be left in a tool holder.

thanks again for the tip

[raynerd]

Jim .... 


Chris

[cidrontmg]

My take on the theme.
The bearings are not the same size - for no other reason than I had these available when I made it. Theyīre 22x8x7 mm and 19x7x6 mm. The bigger bearing axle is tilted 10 deg, so the tool holder has a bit more clearance when the bearing is running in contact with its full width. Thatīs in no way absolutely necessary, but itīs sometimes useful (not often!). The bearings and the big bearing axle is Loctited with 270, thatīs pretty permanent. So if ever they jam, Iīll just make another. But the bearings were used when I made this many years ago, and they probably outlast me anyway. I use this quite often, it permanently occupies one QC tool holder.




Note: itīs now in the tool holder for indexing radially. To index axially, loosen the tool holder fixing screws, and flip it over (=small bearing pointing left). And re-tighten the fixing screws...   
Donīt waste time trying to get it to centre height, it doesnīt have to be exactly spot-on, just thereabouts.