machining estimate

machining estimate

Joined: October 15th, 2015, 1:31 pm

September 28th, 2017, 6:07 pm #1

i know it will vary from place to place, i will be looking for a local shop to do a simple, 30mm diameter counterbore 1 mm deep in a 2mm walled aluminium box. it will be laid out fro them (at least the centerpoint) what would be a reasonable charge for this?
2003 BIOHAZARD ELECTRO COCKER
Quote
Like
Share

Joined: October 28th, 2014, 1:06 am

September 28th, 2017, 8:44 pm #2

There are a lot of missing details that could radically change the cost. Such as how many need to be done? What are the actual tolerances? What is the penalty for failure? How time critical is it?

If you only need one, and it's not too big a deal if it gets botched, you may get a local school or maker space to do it for free. But they won't be able to help you if it's a production run. If you need 100 of them tomorrow, with really tight tolerances, you may not be able to find anyone that can do it for less that $$$$$!

Just off hand, I'd guess about $10-$20 for one, but that is only a wild guess not knowing the time & tolerance restrictions.
Quote
Like
Share

Joined: January 1st, 1970, 12:00 am

September 28th, 2017, 9:56 pm #3

A typical job-shop machine shop has an hourly rate anywhere from $50 to $200 an hour, depending on capability, backlog, and so forth.

Most will charge one hour minimum, even if the job takes 20 minutes, and more than a few will charge two as soon as you're more than a few minutes over that first hour.

Then again, some shops are fairly friendly and will be glad to help you out- if you're not in too much of a hurry, they may put it in with some other low-priority jobs for when the employees have a few minutes between jobs, or finished one job but it's too late in the day to start the next big one.

And yes, you need to have your ducks in a row when you take it in- full dimensions are a minimum requirement, drawings would be ideal. For a single simple job, an actual printout paper would be superior to trying to give them a CAD or other digital model. Do NOT just say "take off about this much" or anything like that. Unless you're leaving part of the design work up to us- and are willing to pay for it - we want hard numbers and acceptable tolerances.

Doc.
Quote
Like
Share

Joined: October 15th, 2015, 1:31 pm

September 28th, 2017, 10:26 pm #4

i do have a full technical drawing for it, but what i'm hearing is it might be better to bribe the machinist at work to do it during his lunch(i hear he likes bagels).
2003 BIOHAZARD ELECTRO COCKER
Quote
Like
Share

Joined: November 30th, 2014, 1:36 am

September 28th, 2017, 10:42 pm #5

"G-Jobs" or "government jobs" are fairly common in some environments. If it's a simple matter of chucking it up on a lathe and boring out a hole it won't be a problem. If that hole has to be positioned within .001 of true center, the hole be axially true and a close bearing fit that's another can-o-worms entirely.
Quote
Like
Share

Joined: October 15th, 2014, 12:22 am

September 30th, 2017, 6:20 pm #6

A typical job-shop machine shop has an hourly rate anywhere from $50 to $200 an hour, depending on capability, backlog, and so forth.

Most will charge one hour minimum, even if the job takes 20 minutes, and more than a few will charge two as soon as you're more than a few minutes over that first hour.

Then again, some shops are fairly friendly and will be glad to help you out- if you're not in too much of a hurry, they may put it in with some other low-priority jobs for when the employees have a few minutes between jobs, or finished one job but it's too late in the day to start the next big one.

And yes, you need to have your ducks in a row when you take it in- full dimensions are a minimum requirement, drawings would be ideal. For a single simple job, an actual printout paper would be superior to trying to give them a CAD or other digital model. Do NOT just say "take off about this much" or anything like that. Unless you're leaving part of the design work up to us- and are willing to pay for it - we want hard numbers and acceptable tolerances.

Doc.
you can figure that if N is the beer and chips level cost then M is the cost factor per decimal digit beyond that. your final cost is N^M


so for a $20 job if you want the tolerances 2 digits better then its now a $400 job
Quote
Like
Share