Machining the Perfect Hole | Different Methods Compared!
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- Опубликовано: 5 сен 2024
- What's the best way to machine a perfectly round hole? Should you bore it? Should you CNC machine it? Let's find out!
So you got a blueprint given to you. The part on the blueprint features a hole with tight shape requirements. What would be the best method to achieve the perfect roundness? Is it ok to just drill it? Should you drill it and rim it? Should you drill it and bore it? Or should you do it on a CNC mill?
Derrick Hogan, CNC technology instructor at North Georgia Technical College, answered the question for us.
He machined the same hole using different methods, analyzed the roundness of each hole using a CMM, and then compared the results.
Which method do you think was the most accurate? Watch the video to find out!
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This video is part of our new video series: ” LEARNING FROM THE PROS”!
We are collaborating with educators from the most advanced technical schools around the country to provide you with tips and tricks, educational videos, and machining technology insights that will help you become a better machinist and learn something new about our beloved metalworking trade.
This project, presented is part of the North Georgia Technical College's tool&die program.
To learn more about the CNC machining program at North Georgia Technical College visit northgatech.ed...
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#machining #drilling #CNCmachine
For a fair comparison you should have used the cnc mill for all operations drilling, reaming, boring and milling. I've seen people get a lot better results with reaming and boring operations.
For sure. I bet that Mazak has way better spindle runout than the Bridgeport.
@@Thewaldo12345 my thoughts exactly. I think spindle runout is the cause of the deviation.
@@scottnoble7979 if he wants the best results I’d be curious to see how a jig borer or jig grinder turns out.
I ran some diaper parts on a mazak in 01. We had to ream because the mill bore would leave the bottom way bigger. That had to do with xy and z all being on the head. The reamer didn't care.
@@travisthomason8869 that just needs the parameter fields correcting
New to the channel, but very good info to digest and apply to my learning curve. At 68+ and only having older mill and lathe for personal use, I am trying to talk the Bride into let me own a small CNC. Wish me luck,,,:)>. Bear in TX.
I wonder did you use a torque wrench and the same vice on all the tests? I wonder if the different pressures from the different vices had a affect on the results. Also maybe try the boring head in the cnc?
The best way to get a round hole is to bore it! The problem with the bored finish is he used a HSS boring bar instead of a Inserted Boring Bar. I guarantee you can get a mirror finish with the right insert. Plus I wouldn't use a wobble dick boring head with a small dia. boring bar. Too much deflection! When you bore a hole you go through then BACK BORE the hole to take out the taper. I've bored thousands of holes for Leader Pin and Bushing holes for Die Sets and Mold Bases in my 40 years in the trade. I know what I'm talkin about.
My boss use to get crazy with me when I bored back out but it the only way you know.
you may get great results but it still won't beat a hone
I see your Titans of CNC class project in the background. Nice!
Jig grind for best location, cylindricity, surface finish
Would boring on the lathe in a 4J give better results than the boring head+mill approach? Seems like it would be more rigid.
Good video but you really should be getting at least a 64 finish with that boring bar any less and its not going to be a good test of what you get. If you get a sharp reamer with proper speeds and feeds you can hold tenths if you know what your doing.
We always drill / boar / ream to final size if critical BUT CNC circular is plenty good for many things which is why you see so much thread milling
that depends on what you call critical, reaming is never going to be the best but if it works for your application it is cost effective.
@@martinfidel7086
We bring bearing cast iron bearing housings to a .0002 to press in the outer race and if needed will hone
@@tommays56 IWhat measuring equipment do you use to check that dimensional quality is correct ?
@@martinfidel7086
Ring Gage and dial bore all certified
You do realize shops did precision work before the RUclips CNC craze
@@tommays56 so in essence then you are only checking the diameter at what can be described as random depths within the bore ? It's interesting, because I come across this a lot, how do you measure for straightness from end to end of the bore ? how about maybe you machine it dead straight but how do you check at which angle you have machined it too ? because a ring and bore gauge won't allow you check either of those irregularities
nice video. next time indicate your reamer. it was running out pretty bad
I love the TITAN-1M on his table.
When I am milling the holes deeper than 1x tool diameter, it becomes a cone like. I guess that is because of tool deflection. How can I get rid of that?
What kind of tool path are you using? What I do is usually predrill a pilot hole - so let’s say we’re doing a 1” hole through 1” steel - I’ll drill it out at say 15/16” (or whatever feels good and close).
After that, if I’m feeling very fancy, I’ll use a helical toolpath with a 1/2” endmill leaving .01” stock on the walls, then come in with the same tool at full depth and do two circle passes with a spring pass to hit final size. You usually eliminate taper that way.
There’s lots of ways of doing it - the helical probably isn’t necessary - and you can always sub out contour multi-passes for the circle mill.
Why would a reamer out perform a boring head?
A scientific demo/teaching video yet students performed the work and you had to make excuses for them at least twice at the CMM for bad technique. You can visually see the run out on the manual machine both on the drill and reamer, of course the boring head is producing garbage. Predrill an undersized hole by .001-.005, minimize the stick out on that reamer and throw it in that Mazak and that should be your best hole. Difference in vice clamping force between CMM and CNC can warp your hole. Are the vice parallels in the CMM contacting the same RAW edges/surfaces as the were in the CNC or did you rotate it 90 degrees throwing off your “perpendicularly?”
I would like to see all 4 but in a cnc machine
You won't beat a honing process with any of those mentioned above.
I need to make a hole as close to 0.25" in a 3" thick UHMW-PE spool that will be riding on a piece of 440 stainless steel shafting with a known tolerance of 0.2490" - 0.2495" in a submerged freshwater application, what method would you use to get a very precise 0.25" hole -0.00/ +.0020?
If you have some spare stock around where the holes need to be, put pilot holes in there and run a 0.25" gundrill.
@@sicstar Thank you
@@chrisdaniel1339 Actually! Better use one that is 0.2490" ! ... smh sry...
Too much adverts
afaik a reamer should be leaving a nicer finish than that
I love the instructional videos, great idea. But honestly I think it's a bit long-winded and the background noise is a bit distracting / unpleasant.
Hope you can understand ;)
really cool video! you can tell the cnc is setup for students that probe cycle is super slow :-)
"Students have a tendency to not do quite the right thing....
Who? Me?
Surely not!
Did i just see a titan building block in the background on the CMM