I remember a time,when we made split bushing grinding fixtures ,do our own heat treating.i made many holders for milling ,surface grinding fixtures. Those were the days
Yeah, you honestly just step down endmill sizes until you use and endmill that corresponds to the smallest radius. If the d shape requires there to be a 0.0312 radius in the corner, then you know you need to use a 0.0625 endmill as a final tool.
A question on the design, not your execution. Is the part being pulled down onto the head of the insert or onto the base plate? If it’s the base plate what keeps the plug from being drawn out by the clamp screw? Better option in that case is slip fit the plugs in and hold them in place with screws from the bottom. If the plugs are the wear item would hardening and grinding make them last longer?
When making the buttons the smaller diameter could be left big. Then the complete d can be cut on the CNC mill. The large diameter would repeat accurately in the vee so the d will always be concentric to it, this is the reference, not the small diameter, no need to clock up the parts every time. The interference could be the same all around using cutter comp instead of biasing it on the flat and a nice lead in chamfer added. Moving on from that, the whole part, d shape, locating diameter and tapped hole could all be done on the mill and parted off to length. Or cut off with a slitting saw. The cutter would leave a sharp internal corner, unlike the turning tool. Not quite one hit machining but all relevant features are accurately machined together.
Did you mill a slot and press in a key to achieve the D shape. It is a common way to locate punches and dies. It is simpler to accurately machine round holes and then fill in the flat with a key. It leaves sharp internal corners so no need to chamfer the inserts leaving a longer engagement with the flat. The part can be machined on a standard mill easily to suit standard off the shelf keys. I tend to use a hardened dowel instead of a key, it eases installation and wears well.
Thanks for the opportunity to ask a few questions. On the pin end diameter, it seems counter-intuitive to use a finer grit wheel on tiny diameters. Smaller parts quickly heat up as they have no significant mass to dissipate the heat, so a cooler cutting wheel with a larger grit would seem the ideal choice. Removing the delicate pins when damaged looks to be a pain unless the hole goes all the way through. Is there any reason why you never reamed all the way through? The height above the plate can easily be set by adding an appropriate depth counterbore of 0.225" in your fitting bar. By setting the height with the counterbored rod, there would be no need to grind them all the same length. Regarding the flats on the inserts. Did they all need to be indicated in? I understand that the smaller diameter is not necessarily concentric with the larger diameter that you are holding on. Would you not take a rough cut - measure and then machine off the difference?
Why the D-shaped hole? LOL engineering in 2025. Deal with it. I'm sick of asking questions to engineers with a 4 year degree. I just do whatever they want at this point. Believe me, I have tried. They don't listen. That's why doors are falling off of jets now. Not kidding. I might have to address this issue on another video.
I would understand if someone was concerned that these plugs might work themselfs loose if a 250 pound gorilla cranks those screws in there but on the other side you have those small 30 thou locators so whoever uses this fixture needs to be very carefull anyways. There are certanly easier ways to stop those things from spinning than d shaped holes. I have never seen something like this in a precision application and I'm impressed by Mr. Kerner for pulling this of.
What other ways could you stop the plugs from spinning? I'm just not that experienced in seeing a lot of other methods. Everything looks concentric so could you just make everything round and do a tighter interference fit or just eat the cost and machine from solid?
This looks like a job for a Moore Jig Grinder but you got it done on a CNC vertical mill. I would like to know how you milled the flat in the D shaped hole. Looks like a few Bozo goofs in the Kurt vice jaws...
Always Interesting seeing how you approach things. Thanks for the video!
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Never thought of taking apart an anvil mike to measure height. Thanks for the video Phil.
I remember a time,when we made split bushing grinding fixtures ,do our own heat treating.i made many holders for milling ,surface grinding fixtures. Those were the days
My only question is , how were the female D shaped holes machined?
I came to ask the same question.
He must have interpolated the finish bore with a tiny diameter end mill is my
guess.
I've thought that too but it seems too simple. @@petemclinc
@@petemclincI would send it out for edm.
Yeah, you honestly just step down endmill sizes until you use and endmill that corresponds to the smallest radius. If the d shape requires there to be a 0.0312 radius in the corner, then you know you need to use a 0.0625 endmill as a final tool.
A question on the design, not your execution. Is the part being pulled down onto the head of the insert or onto the base plate? If it’s the base plate what keeps the plug from being drawn out by the clamp screw? Better option in that case is slip fit the plugs in and hold them in place with screws from the bottom. If the plugs are the wear item would hardening and grinding make them last longer?
Looks like smoke and mirrors, no design can have so many deliberate errors. No toolmaker would leave a sharp edge on the d shaped holes 101.
When making the buttons the smaller diameter could be left big. Then the complete d can be cut on the CNC mill. The large diameter would repeat accurately in the vee so the d will always be concentric to it, this is the reference, not the small diameter, no need to clock up the parts every time. The interference could be the same all around using cutter comp instead of biasing it on the flat and a nice lead in chamfer added.
Moving on from that, the whole part, d shape, locating diameter and tapped hole could all be done on the mill and parted off to length. Or cut off with a slitting saw. The cutter would leave a sharp internal corner, unlike the turning tool. Not quite one hit machining but all relevant features are accurately machined together.
Would you ever do something like heating the plate up so the pucks slide in easier? What would be the considerations?
Did you mill a slot and press in a key to achieve the D shape. It is a common way to locate punches and dies. It is simpler to accurately machine round holes and then fill in the flat with a key. It leaves sharp internal corners so no need to chamfer the inserts leaving a longer engagement with the flat. The part can be machined on a standard mill easily to suit standard off the shelf keys.
I tend to use a hardened dowel instead of a key, it eases installation and wears well.
One more vote to see how the D shaped holes were done please
Thanks for the opportunity to ask a few questions.
On the pin end diameter, it seems counter-intuitive to use a finer grit wheel on tiny diameters. Smaller parts quickly heat up as they have no significant mass to dissipate the heat, so a cooler cutting wheel with a larger grit would seem the ideal choice.
Removing the delicate pins when damaged looks to be a pain unless the hole goes all the way through. Is there any reason why you never reamed all the way through? The height above the plate can easily be set by adding an appropriate depth counterbore of 0.225" in your fitting bar. By setting the height with the counterbored rod, there would be no need to grind them all the same length.
Regarding the flats on the inserts. Did they all need to be indicated in? I understand that the smaller diameter is not necessarily concentric with the larger diameter that you are holding on. Would you not take a rough cut - measure and then machine off the difference?
Thank you sir
Why the D shaped holes? Looks like a concentric locator.
Why the D-shaped hole? LOL engineering in 2025. Deal with it. I'm sick of asking questions to engineers with a 4 year degree. I just do whatever they want at this point. Believe me, I have tried. They don't listen. That's why doors are falling off of jets now. Not kidding. I might have to address this issue on another video.
It must serve a purpose or it wouldn't be there. Probably to prevent the D shaped
plug from rotating in the hole is my guess.
I would understand if someone was concerned that these plugs might work themselfs loose if a 250 pound gorilla cranks those screws in there but on the other side you have those small 30 thou locators so whoever uses this fixture needs to be very carefull anyways. There are certanly easier ways to stop those things from spinning than d shaped holes. I have never seen something like this in a precision application and I'm impressed by Mr. Kerner for pulling this of.
What other ways could you stop the plugs from spinning? I'm just not that experienced in seeing a lot of other methods. Everything looks concentric so could you just make everything round and do a tighter interference fit or just eat the cost and machine from solid?
@@KC3ULCdrill a hole for a dowel pin into the bottom plate would be how I would do it.
Throw all the pins and plugs in the freezer and a heat gun on the plate. They would drop right it with only .001 press
This looks like a job for a Moore Jig Grinder but you got it done on a CNC vertical mill.
I would like to know how you milled the flat in the D shaped hole. Looks like a few Bozo
goofs in the Kurt vice jaws...
The jaws are 20 years old and have done thousands of setups. Shit happens.
Blame those apprentices...