Now to adjust tool height I set the caliper on end on the cross slide and adjust the tool bit until it just clears the outside movable jaw on the caliper.
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| Setting tool bit height. I want the bit to just graze the caliper as it slides under the jaw. |
Monday, March 9, 2015
Lathe: Setting Tool Bit Height
I had a hard time quickly and accurately setting my tool bit height, and finally found a solution using an old inch -only dial caliper I didn't use anymore. After chucking a piece of aluminum in the lathe I took a couple cuts. I then measured from both the top and bottom of the turned portion to the top of the cross slide. Averaging those measurements gave me the distance from the top of the cross slide to the center of the work. I then set my old dial calipers on end on top of the top slide and adjusted the outside movable jaw until it was exactly that distance from the cross slide.
Now to adjust tool height I set the caliper on end on the cross slide and adjust the tool bit until it just clears the outside movable jaw on the caliper.
Now to adjust tool height I set the caliper on end on the cross slide and adjust the tool bit until it just clears the outside movable jaw on the caliper.
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Is it possible to use a steel ruler to precisely set the tool height against center of round workpiece - I have seen suggestion in one site and is very helpful practically - set the ruler between work and tool edge - if it stays exactly vertical, then tool edge is exactly at center of round work
ReplyDeleteUsing the ruler method doesn't work for every shape of tool bit and it's also an iterative process where you make an adjustment, measure, repeat, whereas using my dial caliper is a one step process. However, I will use the ruler method to double check the tool bit adjustment from time to time.
DeleteI have given it a try and I can get just a good results by setting it by eye, when you get close to centre, it is not very accurate
DeleteI found my lathes center by facing off a bit of scrap stock with the tool set deliberately low, you should have a noticible 'pip' on the end of the part.
ReplyDeleteIf you have a QCTP then slowly adjust the height up until there is no pip and the swarf terminates cleanly at the center (stop the machine and feel it, if you've gone too high youll have a nipple rather than a pip)
If you have a standard tool post like me i just take a few more passes and measure the o/d of the pip, half that figure and shim the tool accordingly,
Once you have your tool on centre why not turn down a bit of bar that can sit on your ways (or your cross slide) that is flush to your correct tool height, to use as a reference? (i would cup the base to allow it to sit over small chips etc)
I've used that method before, but I find the caliper method to simply be faster. Plus, I had old calipers just sitting around not doing anything.
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