Gallery, Projects and General > How do I??
How do I.... accurately measure a tilted hole?
sparky961:
Ok... fed. Much happier now.
Thanks for the clarification. Yes, there were definitely some important things left out the first time around. I get what you're saying now.
Overall, I like the approach - mainly due to the simplicity (though we do need to make a punch). However, one thing that bothers me in this case is the ratio of diameter to bore depth for the hole in question. With the diameter being much larger than the depth, anything slid down the bore will have a tendency to cock and/or bind. For this reason I wouldn't trust that a transfer punch would provide a mark that's aligned with the bore's axis.
The mathematical approach relies heavily on an accurate angular measurement as well, which tends to rub me the wrong way. In this case, we don't know how fancy Ade's measuring tools are. My original setup only relies on the ability to align/adjust the part on the machine and read an indicator; essentially using the machine as a CMM.
Now if the constraints included only a protractor and drill press, I'd be all over your idea. :beer:
sparky961:
--- Quote from: Lew_Merrick_PE on November 22, 2015, 09:59:53 PM ---Such things have traditionally been accomplished using (old name) Tooling Balls that are now called shoulder construction balls
--- End quote ---
I'm interested in learning more about how these are used in practice. Do you know of any useful links, or would you be interested in writing up a separate thread showing some obscure but indispensable uses?
Joules:
My assumption was you are angling the mill head, or you have an angle plate on the mill bed ? Apologise for missing that in my description.
Lew_Merrick_PE:
--- Quote from: sparky961 on November 23, 2015, 06:43:18 PM ---
--- Quote from: Lew_Merrick_PE on November 22, 2015, 09:59:53 PM ---Such things have traditionally been accomplished using (old name) Tooling Balls that are now called shoulder construction balls
--- End quote ---
I'm interested in learning more about how these are used in practice. Do you know of any useful links, or would you be interested in writing up a separate thread showing some obscure but indispensable uses?
--- End quote ---
Actually, I have started this, but it is an as time is available (something currently in short supply for me) task. I have taught seven local machine shops how to use tooling balls over the past year. Something that was part of my second six months as an apprentice back in the mid-1960's!
AdeV:
Just for clarity, I've thrown together a CAD representation of what I need to do. As I forgot to bring the USB stick with the plate drawings to work today... I've re-created the plate as a simple block...
Not included are the gear on the bottom of the green shaft (for that I will use the original), nor is the "cap" and single-tooth "gear" wheel shown, nor the sensor mount. I'll do those later.
For the purposes of drawing up the final valley plate, this will do me; but when it comes to making it, as has been suggested, I need to be within a gnat's pubic hair's width of exactly the right place, or it's just not going to work properly. As far as getting everything in the right place for milling the hole:
1) I'll make a jig with 2 dowel pegs & 2 screw holes in opposite corners, these will allow me to both accurately locate, and secure, either the original valley plate, or the new one, to the machine in exactly the same place.
2) Jig will be mounted to the angle plate, angle plate mounted to the machine, align jig to be parallel to table.
3) Tilt angle plate until a dial gauge run around the outer-ish edge of the dizzy mounting flange reads zero at the four compass points at least, preferably fluctuating only with the roughness of the metal. That gets me the exact angle
4) Use a concentric dial gauge (? I think that's what it's called) to centre the quill over the bore hole.
So now the quill is directly over the centre of the hole, at the exact angle needed to bore it out.
5) Switch original plate for new plate. Mill the boss flat (to make the drilling easier, but also to mount the top-hat cover)
6) Drill/bore holes as required.
Quite easy really, once someone's pointed it out to you :bow:
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