Rotary Table Theory Question

[Weldingrod1]

Yike! Chimpo strikes again!

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[ChandlerJPerry]

Well that's a real bummer. I don't suppose there are any parts available either.

That is correct! Not to completely derail this thread from the original topic. Just wanted to share my aggravation.

Relating back to to original issue, someone in a Facebook group I'm in suggested a pretty novel idea, which is to bottom out the quill and then set the depth of my bore. Effectively using the end of quill travel as my depth stop. My machine has plenty of Z travel on the knee so I am thinking this may be my approach, with the quill snugged up and fed slowly by hand.

 

[Firstram]

That is correct! Not to completely derail this thread from the original topic. Just wanted to share my aggravation.

Relating back to to original issue, someone in a Facebook group I'm in suggested a pretty novel idea, which is to bottom out the quill and then set the depth of my bore. Effectively using the end of quill travel as my depth stop. My machine has plenty of Z travel on the knee so I am thinking this may be my approach, with the quill snugged up and fed slowly by hand.

That will reduce the rigidity as much as possible! Ideally, you should always use the least amount of quill as possible! Remember, quills are for drills.

 

[tq60]

Lock the spindle and raise the table.

Make first cuts with a hole saw.

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[Parlo]

What is the plan to align the angled bores with the parallel bores, a tooling ball setup?

 

[verbotenwhisky]

Hey all, I have a question regarding theory of operation with a rotary table. Machine is a standard knee style mill. Here is a section view of a part I am interested in making that I designed (possible customer paying job, don't have full confirmation yet but trying to plan everything out in advance):
View attachment 501792

View attachment 501790

The bores are both 3 inches, although the upper bores are angled 5 degrees. I do have a tilting rotary table that I am planning to employ to aid with this. For the straight bores I planned on using some kind of 2 7/8" annular cutter/hole saw/etc to knock out the bulk of the material through the whole part while cutting the smaller ID, and then using an endmill with the rotary table to finish the bore, easy enough right? I figured I would do the same thing to finish the angled bores until I realized that the rotational axis of the table won't be aligned with the bore axis if the part is fastened flat to the table. Once the rotary table angle is set to 5 degrees, I wouldn't actually be able to make a circle with an endmill because the part would not be rotating about that bore, right?

Initial thoughts on how to overcome this are to use a boring head for the angled bores with the rotary table holding the 5 degree position. Definitely an option but kind of slow and fiddly, and I would be making four of these pieces total.

My second thought would be to make a basic 5 degree fixture plate/block that I could secure to the rotary table and then the part to that, in order allow the bore axes of the part and rotary table to align, and then go forward with my original approach using an endmill.

Third idea would be to employ a sine plate instead of a one off fixture in conjunction with the rotary table, although I don't own a sine plate (maybe a good excuse to get one?).

Am I on the right track here? Totally overthinking this? I would welcome any advice/feedback!

I would use the tilting rotary table to accurately position the bores and I would get the bore close then finish the bore to size with a boring head.

 

[Parlo]

I would use the tilting rotary table to accurately position the bores and I would get the bore close then finish the bore to size with a boring head.

When the part is tilted and the bores are already machined ( the ones square to the part face ) indicating them would show an ellipse. I understand that the averages of the major and minor diameters can find the center of the bore but the position depends entirely on how deep the stylus is in the bore.

 

[verbotenwhisky]

When the part is tilted and the bores are already machined ( the ones square to the part face ) indicating them would show an ellipse. I understand that the averages of the major and minor diameters can find the center of the bore but the position depends entirely on how deep the stylus is in the bore.

If your table is set at 5 degrees to the CL of your z axis, you will get a round hold at that face angle and when you rotate your table 180 degrees you'll get the other. Yes, finding proper center will require a 5 degree ellipse I cheat, I drawing it in CAD then rotate it 5 degrees and do a horizontal dimension from the reference point I can use on the machine to the canter point I want the angled hole to line up with then on my machine I line up with the reference point and using the DRO and move to that dimension..

 

[ChandlerJPerry]

The guy who wanted me to make these for him didn't follow through in the end, but in the interest of the discussion occurring I'll confirm that I had been planning to locate the bores by touching off the outer edge of the part with an edge finder while the part was angled. Using my CAD software I measured the distance in this condition on the model and therefore knew the measurement.

 

[verbotenwhisky]

The guy who wanted me to make these for him didn't follow through in the end, but in the interest of the discussion occurring I'll confirm that I had been planning to locate the bores by touching off the outer edge of the part with an edge finder while the part was angled. Using my CAD software I measured the distance in this condition on the model and therefore knew the measurement.

Excellent, the software is as much of a tool to be leveraged as the mill or lathe and I us it like this all the time.

I would guess that for every 5 paying projects I discuss with folks I end up doing 2+/-. I find their are many folks who have a want or a need until they find out what it will cost and I do not need their project. With that said I will help good folks out that are in a pickel...