End mill through pilot hole

[754]

I think Doozer means .. has an understanding of mechanical concepts and perhaps basic engineering.. being a mechanic to me suggssts being able to perhaps change a waterpump in a 12 cylinder BMW and perhaps wrench for a living.. you do not need that level of knowledge to work around machine tools.

[754]

Maybe using a Clarkson Autoloc to hold endmills and buying threaded endmills is paying off when finishing holes with endmills..

[eKretz]

Yes, of course. A good auto mechanic is absolutely one who understands the
mechanics of mechanism, and more.
There are a few outliers though. I have seen a mechanic beat the brake rotors
off a car, because he did not know that on this car, it had tapered bearings,
and you have to take the cotter key and nut off. Apparently he never ran into that.
Maybe most rotors come off the lug studs. But he beat the rotor off in chunks.
Poor car.

-D

I'll see your hammer mechanic and raise you a level. A former dealership mechanic I know came into my shop one day and asked me to grind a bearing spacer for him to set preload on a rear diff's carrier bearings. So I ground it to the size he wanted. Turned out he made it loose. So I watched as he stuck some shim in between the carrier and the housing, and proceeded to beat the carrier in with a hammer... For about 15 minutes, from several different angles. After I repeatedly asked him if he wanted to just make a new spacer. And if he had a diff spreader... Lol.

[nickel-city-fab]

Yes, of course. A good auto mechanic is absolutely one who understands the
mechanics of mechanism, and more.
There are a few outliers though. I have seen a mechanic beat the brake rotors
off a car, because he did not know that on this car, it had tapered bearings,
and you have to take the cotter key and nut off. Apparently he never ran into that.
Maybe most rotors come off the lug studs. But he beat the rotor off in chunks.
Poor car.

-D

Hanging out at a friends house
Her landline phone was dead,
so I gave her my spare rotary dial desk phone
her kids (in their 20's) had never seen one except in movies
much hilarity ensued

[Dave C]

I know several mechanics that wouldn't know a diff spreader from a can of peas. Also know some great engine builders that have no idea how to align a front end. Mechanics as a trade covers a lot of ground, as does mechanics as a science: but the two are not the same field of study.

[Toolguy]

I find it a lot easier to hit a close size hole with a reamer or boring head than an end mill. My mills are in good trim and I do precision work with them on a daily basis.

[Fasturn]

Someone needs to drag their loose chattering quill or do a better job at cleaning chips out...

Old Marts allot closer with his "no more than .001" for a 10 mm hole...

Oooh nasty.. The OP is not a seasoned Machinist with this type of question. Yeah, with a cheap chi-com mill you can blow out the hole .007 easy. Guys put EM in chuck's and it's worse!
I was just pointing out how bad it might get for him.

On a Hauser jig bore I was holding .0001 all day. No smoke.
Guys throw around precision values, but few really hold them? Wonder which you are ? LOL.... this calls for a Beer~

[old mart]

If you re read my posts #10 and14, you will see that I don't always get a good fit.

[754]

Yes i use boring head a lot for precision. But i often do allenhead counterbores.. thus is where regrind endmills come in handy. Even if they dont cut dead flat thet are still quick and gopd enough., on bike work I want tighter clearance to an alken bolt than a standard counterbore can supply.. wether i have 8 thou of clearance to bolt head or 13 .. it dies not matter much... but 30 thou dont look good..

[Doozer]

I know several mechanics that wouldn't know a diff spreader from a can of peas. Also know some great engine builders that have no idea how to align a front end. Mechanics as a trade covers a lot of ground, as does mechanics as a science: but the two are not the same field of study.

A mechanic and a parts changer are not the same.
A machinist and a machine operator are not the same.

-D

[Doozer]

Oooh nasty.. The OP is not a seasoned Machinist with this type of question. Yeah, with a cheap chi-com mill you can blow out the hole .007 easy. Guys put EM in chuck's and it's worse!
I was just pointing out how bad it might get for him.

On a Hauser jig bore I was holding .0001 all day. No smoke.
Guys throw around precision values, but few really hold them? Wonder which you are ? LOL.... this calls for a Beer~

I have a SIP #4 and a P&W 2A.
I have been working on perfecting that 4th decimal place.

-D

[Fasturn]

I have a SIP #4 and a P&W 2A.
I have been working on perfecting that 4th decimal place.

-D

Yes we had Sips too, but the Houser was by far the most accurate. Sony glass DRO out to 50/ million. Deltronic class X pins for checking size. A wohlhaupter boring was junk, compared to the Swiss Houser head. Crazy RF engineers had us holding T.P. .0001 + - .0001 on the diameters. Much to my chagrin, I was hold it finding a tight spot on the table. Will drive you crazy with spindle warm up and down. Casting had heaters for thermal TCE. Glad you can appreciate Swiss Iron, truly the best of the best. Sips were my next favorite Jig- Bore.

[A.K. Boomer]

Oooh nasty.. The OP is not a seasoned Machinist with this type of question. Yeah, with a cheap chi-com mill you can blow out the hole .007 easy. Guys put EM in chuck's and it's worse!
I was just pointing out how bad it might get for him.

On a Hauser jig bore I was holding .0001 all day. No smoke.
Guys throw around precision values, but few really hold them? Wonder which you are ? LOL.... this calls for a Beer~

Very impressive --- lmk when you get the hang of plunge cutting a hole with an endmill lol beer cracked - beer drank... .007" is what you call "blowing it" chi-com or not... again drag the quill a little and blast out the chips once in awhile...

[Paul Alciatore]

In one word, NO.

I once tried to make some aluminum clamps to grip 1/4" rods, using the split cotter style. Some of them had to enter and exit from the aluminum at odd angles like 30 and 45 degrees. My first attempts were to spot them with an end mill and then use a 1/4" drill bit. This just did not work and my holes were like a drunk sailor.

I then tried a 1/4", carbide, end cutting, end mill. It went straight through, following it's own path and not deviating by any measurable amount even when it passed on one side of the already drilled hole for the rod that would be clamped. The two holes overlapped by about 25 to 40 percent so there was a great imbalance between the two sides of the end mill but it continued on with no deviation. The carbide end mill also entered the aluminum at the various angles I mentioned with no deviation.

I think the carbide helped because it is very rigid. But I also think it may have been OK with a HSS end mill.

I think you can drill your smaller hole either before or after making the larger one with the end mill. It should work either way.


It is curious that the drill bit did wander a lot off course in spite of the lands on the flutes that are designed to NOT cut sideways but the end mill, with flutes that are designed to cut sideways DID NOT. In my mind this can only be explained by the tip angle of the drill bit (118 degrees) as opposed to the 180 degree tip of the end mill.

Does using an end mill where there is a pilot hole already drilled pose any problem ?

[Doozer]

I currently own at least 3 machines that weigh 9,000 pounds each.
Rigidity makes cuts come out accurate. One less variable to contend with.
It is such a pleasure to make whatever you want, and have it come out
as accurate as you desire. I know maybe you are thinking what I am
saying is way overkill for a home shop, but it is such a joy to use my
machines to make my projects.

--Doozer