@@pb68slab18 version we went on was, measure with a micrometer, mark with a crayon, trim with a axe. Zinc chromate, polymide primer and pro-seal, can hide a multitude of sins…
Excellent video! I'm in a similar industry...deep drawing (mostly) die produced metal parts...but we share many concerns. Often the customer might want "a few" parts up front, so we have to include hydroforming or metal spinning along with 5axis laser or some costly fixturing. You hit so many critical points and they are so important. 1) material 2) quantity 3) GDT 4) leadtime 5) surface finish 6) coatings and or rust protection 7) packaging 8) asking if there is a future with volumes that reasonably support the business. 9) in process inspection methods. It's great if a mic or caliper work...but often gets more demanding requiring costly relational gaging to pre-coated material 10) issues multiply on outside processing that are out of your control. Different businesses but very similar alligators to wrestle. Thank you!
I'm retired now and only take on the "fun" jobs that come around in my home shop. The last place I worked went bankrupt due to over tolerance drawings. Parts that could have been + or - an inch and it wouldn't have mattered were drawn to .0005". What it was, was a bunch of engineers that were unsure of themselves as engineers and just slapped a tighter than needed tolerance on everything. The inspection department was no better and rejected many otherwise perfectly good working parts. If you tried to bring notice to this their reply would be " if you can't build these we'll find someone who can". I and others there were journeyman machinist with years of experience. That's why they folded up. We could make anything they could design and draw and we did so. It was sad and like watching a drowning man going down and not being able to help him. I was within arms reach of retirement anyway so it effected me very little.( more fishing time) Some of the younger guys didn't fair so well and I felt bad for them. I also felt bad for all the vendors that lost money and was left holding an empty bag when the dust settled.
I work for a structural steel fabrication shop and have a perfect example of tolerance stack, but going the other direction. Several years ago we were building for a Seattle area high-rise and our typical (unless noted) tolerance for most features is plus/minus 1/16". So we hold this tolerance per detailed member, and the jobsite starts stacking columns, full contact end to end, and near the top of the building, they measure overall structure height, and it's too tall, by several inches. Cue the fiasco playlist.
This is more twenty years back when GE ask us to quote machine parts for them, because they have burnt all machine shops by not paying them due to the postulate, that the part didn't hold the tolerances but GE used strange enough the parts that was produced. At that time GE would rather use 2-3 lawyers than paying the machine shop. Of cause in a good time shops where very reluctant to produce for them again.
As a 2 man job shop owner, it seems to me that we are at an all time high of discrepancies between cad models, prints and instructions be it PO’s, verbal instructions, or written instructions. Revs incorrect, correct rev prints not supplied etc. and when you bring up to the customer, it seems like it takes 2-4 days to get a response. You either have to wait for them to reply, move on to another job, or go with your gut instinct on the discrepancy at hand. It seems to me like with the lack of competent workers in any industry, companies are forced to go with less qualified people (engineers in this case) who are making decisions/ tolerances that as you mentioned have no idea what actually matters. Not sure what the answer is. Just frustrating.
Our biggest customer has a brand new team every year and every year we have to teach them how to design for the real world and every time things are going good a lot of people quit or get fired and we start all over again
Not machining but electronics: I once was approached to make a "neuro-stimulator". This guy thought he would be able to think better if he had low-level current pulses being pushed through his head, and wanted someone to come up with and build an apparatus to do it. My response and recommendation: if the customer wants something for any stated purpose that would be catastrophic if it failed in any way, back off - fast. Don't even give advice.
We bring in a few mechanical engineering students every semester for work experience. Now I learned mechanical drafting with a drafting table, T-square, Leitz instruments and a PENCIL. The CAD drawings these kids make are almost comical! Dimensions coming from every corner and surface! I learned to dimension from center, or upper right corner, just like you read. Plus ya go from a back stop, back vise jaw, and a stop on the left. Accumulating and/or over-lapping tolerances are usually the by-product.
I got rid of a couple of customers that absolutely wanted to quote their drawings in metric where 2 inches features would have been OK, but they were always quoting 50 mm. metric material is very difficult to get here. Every parts that could be standard inch dimensions were quoted in metric like, 12 mm for 1/2 etc. No more problem with them.
Another serious red-flag is when they ask for high-volume pricing, but only a small quantity to start, and no ramp-up plan. So, they come to you and say "I'm going to need 10,000 parts in the next quarter...but this quarter I only need 20." If they're not willing to give some assurance, preferably a purchase order with delayed delivery on the other parts, very often they're blowing smoke and don't really have any production ramp-up plans, only wishful thinking. Sure we all love startups, but a lot of time they haven't really REALLY looked carefully at their ability to capture their market and reach their customers. Many many businesses fail by thinking their volume is going to be hyooge, but not having a concrete plan to get there. If the time setting up a volume-production infrastructure on your end is even a tiny fraction over the basic make-it-ship-it costs, you're potentially going to end up eating all that startup costs when they fall flat. So, beware!
This is HUGE and I've seen it more times than I can count, both in my shop and others. When I get RFQ's like this crossing my desk, I'll always break out the pricing to "1st order (20 parts" = $x per part," and then another line for "Subsequent orders" with a minimum order quantity. Usually when they see all the tool-up, fixturing, programming, etc slapped onto that first order, it's a bit of a shock. If nothing else, it helps separate the serious potential customers from the tire-kickers and people looking to take advantage!
@@iansandusky417 In the EE world where I mostly live, we call that "NRE"...Non-Recurring Engineering charges. We charge 'em up-front, and with full markup over our costs. If they can't afford to fund the development, then they certainly can't pay for the production!
It's acceptable to define tolerances inside the model file with the blueprint only defining specs and process requirements. The print might have a few views of the part with some reference dimensions....Be very careful dealing with those. Another type of print might only contain Basic Dimensions for all features with the Datum Structure defined in a b/p note. The note will probably also contain the tolerance for all features. An example of tolerance : [ profile .001 (S) A-B-C ] ..... this sure makes the engineer's job easy but kills the shop that wins the bid. Always be aware of updates to geometric dimensioning and tolerance requirements. Also be certain that you completely understand the outdated GDT requirements for those old prints.
The company where I work we machine alot of plastic. We got a part that could literally have been made with + - .01 tolerance and it wouldn't have affected fit or function. Instead we got .0005 over the entire contour. AND 100% CMM sorting - For a screw driver handle.
Not really involved in the quotation process but I do hear my boss complain sometimes that some people are asking for the cost to be lower than what the cost of the materials would be.
I would add URGENCY, customers think they throw money and the monkey dance that aint happening....and Missing Info, there are a lot of custumers who conceal information from the manufacturer.
"Hey, just whip that out in that ol' Bridgeport over there. It's just a block with a couple of holes, what do you mean it's going to cost $1000 and you can't do it while I wait?"
Looking at a drawing for the first time to quote, there is no way the Estimator can have an opinion on what needs to be critical and what does not need to be critical from the design intent. I think what would be a better topic for discussion would be examples of how Engineers might format drawings that help make the design intent clear from the machinist point of view so when the part is finished it meets the Engineers expectations.
After this one, the old man asking to fix his lawnmower doesn't look so bad🤣
You ain’t wrong there!
Great topic!
Sounds like drawings in the aviation industry.
Ever heard the analogy, measure with a micrometer, mark with a crayon, trim with a axe…
Thank you very much sir!
Chop to length, hammer to fit, paint to match! 😆
@@pb68slab18 version we went on was, measure with a micrometer, mark with a crayon, trim with a axe. Zinc chromate, polymide primer and pro-seal, can hide a multitude of sins…
Excellent video! I'm in a similar industry...deep drawing (mostly) die produced metal parts...but we share many concerns. Often the customer might want "a few" parts up front, so we have to include hydroforming or metal spinning along with 5axis laser or some costly fixturing.
You hit so many critical points and they are so important. 1) material 2) quantity 3) GDT 4) leadtime 5) surface finish 6) coatings and or rust protection 7) packaging 8) asking if there is a future with volumes that reasonably support the business. 9) in process inspection methods. It's great if a mic or caliper work...but often gets more demanding requiring costly relational gaging to pre-coated material 10) issues multiply on outside processing that are out of your control.
Different businesses but very similar alligators to wrestle. Thank you!
I'm retired now and only take on the "fun" jobs that come around in my home shop. The last place I worked went bankrupt due to over tolerance drawings. Parts that could have been + or - an inch and it wouldn't have mattered were drawn to .0005". What it was, was a bunch of engineers that were unsure of themselves as engineers and just slapped a tighter than needed tolerance on everything. The inspection department was no better and rejected many otherwise perfectly good working parts. If you tried to bring notice to this their reply would be " if you can't build these we'll find someone who can". I and others there were journeyman machinist with years of experience. That's why they folded up. We could make anything they could design and draw and we did so. It was sad and like watching a drowning man going down and not being able to help him. I was within arms reach of retirement anyway so it effected me very little.( more fishing time) Some of the younger guys didn't fair so well and I felt bad for them. I also felt bad for all the vendors that lost money and was left holding an empty bag when the dust settled.
I work for a structural steel fabrication shop and have a perfect example of tolerance stack, but going the other direction. Several years ago we were building for a Seattle area high-rise and our typical (unless noted) tolerance for most features is plus/minus 1/16". So we hold this tolerance per detailed member, and the jobsite starts stacking columns, full contact end to end, and near the top of the building, they measure overall structure height, and it's too tall, by several inches. Cue the fiasco playlist.
I love that the thread OP was not just roasted in the thread but on a youtube video as well. Lol
This is more twenty years back when GE ask us to quote machine parts for them, because they have burnt all machine shops by not paying them due to the postulate, that the part didn't hold the tolerances but GE used strange enough the parts that was produced. At that time GE would rather use 2-3 lawyers than paying the machine shop. Of cause in a good time shops where very reluctant to produce for them again.
As a 2 man job shop owner, it seems to me that we are at an all time high of discrepancies between cad models, prints and instructions be it PO’s, verbal instructions, or written instructions. Revs incorrect, correct rev prints not supplied etc. and when you bring up to the customer, it seems like it takes 2-4 days to get a response. You either have to wait for them to reply, move on to another job, or go with your gut instinct on the discrepancy at hand. It seems to me like with the lack of competent workers in any industry, companies are forced to go with less qualified people (engineers in this case) who are making decisions/ tolerances that as you mentioned have no idea what actually matters. Not sure what the answer is. Just frustrating.
Incompetent sums up my coworkers in a nutshell 😅. Not saying I'm better, but the decisions they make on even minute things leave me quizzical.
Our biggest customer has a brand new team every year and every year we have to teach them how to design for the real world and every time things are going good a lot of people quit or get fired and we start all over again
Not machining but electronics: I once was approached to make a "neuro-stimulator". This guy thought he would be able to think better if he had low-level current pulses being pushed through his head, and wanted someone to come up with and build an apparatus to do it. My response and recommendation: if the customer wants something for any stated purpose that would be catastrophic if it failed in any way, back off - fast. Don't even give advice.
We bring in a few mechanical engineering students every semester for work experience. Now I learned mechanical drafting with a drafting table, T-square, Leitz instruments and a PENCIL. The CAD drawings these kids make are almost comical! Dimensions coming from every corner and surface! I learned to dimension from center, or upper right corner, just like you read. Plus ya go from a back stop, back vise jaw, and a stop on the left. Accumulating and/or over-lapping tolerances are usually the by-product.
I got rid of a couple of customers that absolutely wanted to quote their drawings in metric where 2 inches features would have been OK, but they were always quoting 50 mm. metric material is very difficult to get here. Every parts that could be standard inch dimensions were quoted in metric like, 12 mm for 1/2 etc. No more problem with them.
Whoever drew that part can take a hike. That's insane!
Another serious red-flag is when they ask for high-volume pricing, but only a small quantity to start, and no ramp-up plan. So, they come to you and say "I'm going to need 10,000 parts in the next quarter...but this quarter I only need 20." If they're not willing to give some assurance, preferably a purchase order with delayed delivery on the other parts, very often they're blowing smoke and don't really have any production ramp-up plans, only wishful thinking. Sure we all love startups, but a lot of time they haven't really REALLY looked carefully at their ability to capture their market and reach their customers. Many many businesses fail by thinking their volume is going to be hyooge, but not having a concrete plan to get there. If the time setting up a volume-production infrastructure on your end is even a tiny fraction over the basic make-it-ship-it costs, you're potentially going to end up eating all that startup costs when they fall flat. So, beware!
This is HUGE and I've seen it more times than I can count, both in my shop and others. When I get RFQ's like this crossing my desk, I'll always break out the pricing to "1st order (20 parts" = $x per part," and then another line for "Subsequent orders" with a minimum order quantity. Usually when they see all the tool-up, fixturing, programming, etc slapped onto that first order, it's a bit of a shock.
If nothing else, it helps separate the serious potential customers from the tire-kickers and people looking to take advantage!
@@iansandusky417 In the EE world where I mostly live, we call that "NRE"...Non-Recurring Engineering charges. We charge 'em up-front, and with full markup over our costs. If they can't afford to fund the development, then they certainly can't pay for the production!
It's acceptable to define tolerances inside the model file with the blueprint only defining specs and process requirements. The print might have a few views of the part with some reference dimensions....Be very careful dealing with those.
Another type of print might only contain Basic Dimensions for all features with the Datum Structure defined in a b/p note. The note will probably also contain the tolerance for all features.
An example of tolerance : [ profile .001 (S) A-B-C ] ..... this sure makes the engineer's job easy but kills the shop that wins the bid. Always be aware of updates to geometric dimensioning and tolerance requirements. Also be certain that you completely understand the outdated GDT requirements for those old prints.
The company where I work we machine alot of plastic. We got a part that could literally have been made with + - .01 tolerance and it wouldn't have affected fit or function. Instead we got .0005 over the entire contour. AND 100% CMM sorting - For a screw driver handle.
Sheeeesh, yeah that's a spot-on example!
Good information, is that a new broom?
Good eye, it sure is! Big spenders here today!
Good overview.
Thank you very much for checking it out!
Not really involved in the quotation process but I do hear my boss complain sometimes that some people are asking for the cost to be lower than what the cost of the materials would be.
I've seen customers give me +-.0000 or +0-.0001 before. I just grind it as close as I can lol
Gotta love that - I always wonder how they're going to measure it when they receive it!
Good chat.
Thank you very much for checking it out!
This guy is building a time machine... on a budget
gotta harvest that thelemic energy bro
Well explained it could be even better with an example
Thank you sir! There’s a good example on the thread linked in the description if you’re interested!
I would add URGENCY, customers think they throw money and the monkey dance that aint happening....and Missing Info, there are a lot of custumers who conceal information from the manufacturer.
that print is sooooo cursed
hello from spain...good video
Thank you very much!
I just got a drawing that was made in 1950, that actually called out a hole position with +/- .0000
WTH!
"Hey, just whip that out in that ol' Bridgeport over there. It's just a block with a couple of holes, what do you mean it's going to cost $1000 and you can't do it while I wait?"
Bonus tolerance from GD&T?
This is a great video, but the music is terrible. I think most of us have the attention span to get through this without the help of music.
IF it dont make sense,
my #1 answer is,
it was drawn by a woman,
my #2 answer would be
a new engineer.
Looking at a drawing for the first time to quote, there is no way the Estimator can have an opinion on what needs to be critical and what does not need to be critical from the design intent. I think what would be a better topic for discussion would be examples of how Engineers might format drawings that help make the design intent clear from the machinist point of view so when the part is finished it meets the Engineers expectations.
Talk to much, get to the point.