Need help dialing in a part

Upnorth4 · Nov 16, 2017

I’ll try to attach a picture.....

I have a part I need to dial in, it’s a rectangular plate with 5 holes, 4 have a bearing pocket on one side the 5th is on the other side.....

After flipping it I need to align the 5th hole.....

I can go back and forth dialing the pervious 4 holes but it is tedious....

Unfortunately the plate is flame cut so bringing it up against stops doesn’t line it up...

I don’t want I go to the extent of making a jig because I only have three parts to cut, but a jig just might be fast than going back and forth between the holes.

What is the best method to align a bolt hole partern after its been cut and removed?

BSCustoms · Nov 16, 2017

make a fixture. even at 3 parts, a piece of aluminum is cheaper than your time fussing with it. and you can pull the pins and use it again later.

plastikdreams · Nov 16, 2017

Why not just pick up the hole and machine the pocket...it's only one right?

DMF_TomB · Nov 16, 2017

Upnorth4 said:
I’ll try to attach a picture.....

I have a part I need to dial in, it’s a rectangular plate with 5 holes, 4 have a bearing pocket on one side the 5th is on the other side.....

After flipping it I need to align the 5th hole.....

I can go back and forth dialing the pervious 4 holes but it is tedious....

Unfortunately the plate is flame cut so bringing it up against stops doesn’t line it up...

I don’t want I go to the extent of making a jig because I only have three parts to cut, but a jig just might be fast than going back and forth between the holes.

What is the best method to align a bolt hole partern after its been cut and removed?

.
without picture and tolerances hard to say
.
putting tight pins in 2 holes same size and clamping parallel to pins and indicating parallel is one method as well as pin hand tight in drill chuck and in handle more slowly see if it goes in holes without it sliding into hand tightened drill chuck or relatively loosely tightened collet holder

DDoug · Nov 16, 2017

Yup, as others have said (without seeing it) the flame cut edge, mill a small flat
(we call it a witness mark)

Change the holes to be tighter tolerance (known as in process features)
so you can use them to pick up on the other side.

Many parts are made like this, many are not even on the drawing, (for example a bearing cap) with an o.d held to within .002"
While it's just for clearance in service, in process, it's used with a rabbet ring
fixture for the second side machining, to keep 2 bores concentric.

HuFlungDung · Nov 16, 2017

I would mill along one side of the plate (if there is a flat side available) to create a feature that is parallel to a line between two of the holes. Then when flipped, you can still dial in on one of the holes to find your location without having to worry about rotation.

DMF_TomB · Nov 16, 2017

HuFlungDung said:
I would mill along one side of the plate (if there is a flat side available) to create a feature that is parallel to a line between two of the holes. Then when flipped, you can still dial in on one of the holes to find your location without having to worry about rotation.

.
on big castings we call that a proof edge. it is a feature often .35 deep and cut into side only .010" its just for indicating later like after part is flipped.

lionelt · Nov 16, 2017

Upnorth4 said:
I’ll try to attach a picture.....

I have a part I need to dial in, it’s a rectangular plate with 5 holes, 4 have a bearing pocket on one side the 5th is on the other side.....

After flipping it I need to align the 5th hole.....

I can go back and forth dialing the pervious 4 holes but it is tedious....

Unfortunately the plate is flame cut so bringing it up against stops doesn’t line it up...

I don’t want I go to the extent of making a jig because I only have three parts to cut, but a jig just might be fast than going back and forth between the holes.

What is the best method to align a bolt hole partern after its been cut and removed?

Couple of extra tabs added to drill for two tight pins on the plate, that can then be dropped in the mill table slots. Done this a few times on flame cut plate.

Upnorth4 · Nov 16, 2017

Thank you all for the great replies.
Where this shows my inexperience was in not seeing the full picture. I should have machined the single hole first AND cleaned up two sides for a reference.
What I will do is turn some round bar to fit the existing holes the use the program to drill exact locations for those pins.
Yes these are bearing holes, the message I got from my boss is that the H6 fit (.0015 tolerance) applies to the location of the holes.....
I am not a Machinist (yet) I am a Millwright hired to Machinist position. As a Millwright I understand how important bearing pockets are, but I figure that tight tolerance applies to hole and even though the shaft held in these bearings are short the location tolerance is much larger, perhaps .010”, much more of the shafts were longer.

DMF_TomB · Nov 16, 2017

Upnorth4 said:
Thank you all for the great replies.
Where this shows my inexperience was in not seeing the full picture. I should have machined the single hole first AND cleaned up two sides for a reference.
What I will do is turn some round bar to fit the existing holes the use the program to drill exact locations for those pins.
Yes these are baring holes, the message I got from my boss is that the H6 fit (.0015 tolerance) applies to the location of the holes.....
I am not a Machinist (yet) I am a Millwright hired to Machinist position. As a Millwright I understand how important bearing pockets are, but I figure that tight tolerance applies to hole and even though the shaft held in these bearings are short the location tolerance is much larger, perhaps .010”, much more of the shafts were longer.

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i was a millwright 20 years, then a maintenance machinist 12 years, now a cnc machinist 5 years.
just saying it is possible to do more and more shop work making parts ultimately working full time in the shop. when older its much nicer working staying in the shop all the time.
.
often millwrights are subject to a type of discrimination and or are considered inferior and not worthy to be in the shop. dont let the others get to you. often they are just insecure about their jobs. the best machinist will actually try to help you if you ask for advice.

Upnorth4 · Nov 16, 2017

Parts of this job I love, other days it seems I have “pucker” factor for 8hours a day.

This is my second career, formely a pilot. There is an expression in aviation:
“You start with an empty bag of experience and a full bag of luck. The trick is to fill he bag of experience without emptying the bag of luck”
In machining I am finding it is:
“You start with an empty bag of experience and a bag of the bosses patience, the goal is to fill the bag of experience without emptying thier bag of patience”

Another one that fits this job to a T is:
Undo haste makes waste.

Even if I spent half an hour, or much more, looking at the plans this job would have been done yesterday. It’s just hard 6weeks into this job to keep dipping into that bag of patience by going back to the boss every 5mins with questions, I sure appreciate this form!!

HuFlungDung · Nov 16, 2017

Upnorth4 said:
Thank you all for the great replies.
Where this shows my inexperience was in not seeing the full picture. I should have machined the single hole first AND cleaned up two sides for a reference.
What I will do is turn some round bar to fit the existing holes the use the program to drill exact locations for those pins.
Yes these are bearing holes, the message I got from my boss is that the H6 fit (.0015 tolerance) applies to the location of the holes.....
I am not a Machinist (yet) I am a Millwright hired to Machinist position. As a Millwright I understand how important bearing pockets are, but I figure that tight tolerance applies to hole and even though the shaft held in these bearings are short the location tolerance is much larger, perhaps .010”, much more of the shafts were longer.

Often some engineer somewhere will figure he's saving money by not having any reference surfaces machined on the outside of a flame cut part. But somebody, somewhere, has to actually make a decision on where that 'rough condition' is theoretically supposed to be. I tell the guy to NOT FLAME CUT to the exact profile, I need a bit extra to allow for potential taper of the cut process. If the profile ' doesn't matter', then let's make it 1/8" bigger than drawn, and I promise, I won't give a shit if I have to cut 1/8" off it to square it up. I get concerned when I have to go 1/8" under the profile size to get a squared up reference. Plus, going under profile size makes it a bitch to eyeball overall correctness of the part when it is done.

DMF_TomB · Nov 16, 2017

Upnorth4 said:
Parts of this job I love, other days it seems I have “pucker” factor for 8hours a day.

This is my second career, formely a pilot. There is an expression in aviation:
“You start with an empty bag of experience and a full bag of luck. The trick is to fill he bag of experience without emptying the bag of luck”
In machining I am finding it is:
“You start with an empty bag of experience and a bag of the bosses patience, the goal is to fill the bag of experience without emptying thier bag of patience”

Another one that fits this job to a T is:
Undo haste makes waste.

Even if I spent half an hour, or much more, looking at the plans this job would have been done yesterday. It’s just hard 6weeks into this job to keep dipping into that bag of patience by going back to the boss every 5mins with questions, I sure appreciate this form!!

.
depends on the boss but normally better to go ask other machinist for advice than have to tell boss you crashed and or damaged the machine and part.
.
often crashes are just doing a simple mistake like making a typo entering a coordinate. most dangerous time is when you dont have somebody looking over your shoulder doubling checking everything you do after a month or 2 in a new shop
.
i make and use checklists like for setting up job and for running the machine and for recording measurements and any problems. sort of like a pilot checking the plane before takeoff
.
crash picture is 11 ton casting that was big 0.5" on one feature. foundry apologized but none the less i made note to watch facemill approach and approximate depth it will take on all roughing. often this means stopping and walking 50 feet to see other side of part cause its a big part. not suppose to have to do that cause foundry suppose to make casting to correct size +/-0.100", the spindle was so badly damaged they had to make a new one and machine was down for repairs over 6 weeks.

Upnorth4 · Nov 16, 2017

I had my first crash on the peice being discussed here. I missed a Z positive move on the second hole cut and when it moved to the third it drove into the side of the part, tearing the holes out of a Cat40 taper, breaking the pull stud off. A very simple thing was missed, I did “draw” the program but missed the fact is didn’t move up before moving over . Humbling
With just 6 weeks on the job I am hoping I don’t use up too much “patience” too quickly here. I did ask the only other machinist to check my work before running the program again. I am lucky that I got to the Estop before too much damage was done.
I could go on and on about “mitigating” factors, and they are all tools in my box now as things to look out for.

I really like the check list mentality. It works. 10,000 hours as a commercial pilot before the career change prove that. I just need to transfer them forward to this job.......

Limy Sami · Nov 16, 2017

Upnorth, .as a general rule of thumb, when flipping parts that have to have features machined that are in direct relation to features on the other side, fixture making is seldom time wasted .yes of course you can dial it in by clock etc etc, but it's time consuming and very prone to errors.

But with a fixture, with say 2 known datum points that prevent any movement of the part, you have already built in your accuracy!........ and if you think about it, ........when setting out the datums in the fixture, from those it's easy to pick up the exact point of the critical feature needed on the other side

HuFlungDung · Nov 16, 2017

Upnorth4 said:
I had my first crash on the peice being discussed here. I missed a Z positive move on the second hole cut and when it moved to the third it drove into the side of the part, tearing the holes out of a Cat40 taper, breaking the pull stud off. A very simple thing was missed, I did “draw” the program but missed the fact is didn’t move up before moving over . Humbling
With just 6 weeks on the job I am hoping I don’t use up too much “patience” too quickly here. I did ask the only other machinist to check my work before running the program again. I am lucky that I got to the Estop before too much damage was done.
I could go on and on about “mitigating” factors, and they are all tools in my box now as things to look out for.

I really like the check list mentality. It works. 10,000 hours as a commercial pilot before the career change prove that. I just need to transfer them forward to this job.......

If you are 'finger camming', you learn fast to run the complete program through in air cut mode first to watch for obvious blunders. You gotta be real focused, too, or you can still miss things like no return to rapid clearance. I'm glad I proof everything on the computer before I send it up, it's the modern way to avoid PTSD on the job

Upnorth4 · Nov 16, 2017

I agree 100% on the fixture, how ever I’m 6weeks new to this shop and the boss wants it done this way. Which makes me feel very new, struggling to dial his in.

Toughest boss I have worked for,

NAST555 · Nov 17, 2017

I was going to reply yesterday that I would find out if you could machine two of the profiled edges clean and do that for reference when flipped but work got in the way. Also 2 dowel or locating reamed holes could have helped you if it was allowed. My last suggestion would have been to turn two plugs and bolt them to the table that locate inside the bores for location when flipped.

After reading your description it is a little weird for me to understand that millwright's are not held a bit higher over there. Over here it means that you would have a bit of a higher wage compared to an ordinary machinist. When I did my trade test the millwrights did similar marking off,bearing fits and assembly and just got a bit more involved with the 5 hole flange, drilling and hole locations having a few more features, to us "Fitter machinists". Then we obviously got the machining part and more in depth with assembly alignments and they went off to do the electrical/electronic side of their test. It could maybe be that because of our mining industry that in that sector millwrights are more sought after than machinists?

Good luck on your new venture... and rather prove ALL your programs out with a dry run in the beginning. Could save you a lot of headaches.

Upnorth4 · Nov 17, 2017

Millwrights here generally get a better wage. When I took this job I was under the understanding that there would be a lot more field work, more line boring and assembly work with heavy equipment techs. I have only been on the job for 6 weeks and it has all been machining on manual mills and this past two weeks on a conversational CNC mill. Millwrights and Machinist here have a fist year program that is identical, second year millwrights cover a lot of welding and the last two years cover automation and alignment.
So while I did a fair amount of CNC “button pushing” last year while also doing maintenance and fabrication for the oil industry last year this is all about six years old stuff for me.
I love the area I am in now and I’m sure the “new guy” issues will settle out, but yes a Millwright position somewhere else would pay a lot more.

bryan_machine · Nov 18, 2017

A successful pilot, especially a commercial one, gets good at looking ahead and anticipating things, and saving hours (and crashes, huge bills, unhappy phone calls from the aviation authority) by spending minutes.

As you learn about what you are doing (the equivalent of that first 100 hours flight time...) you will find that same looking/thinking ahead is key.

But you have to learn what to look ahead for.... It will come....

Need help dialing in a part

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