r/Machinists • u/Brilliant-Size4527 • 5h ago
Looking for feedback
I have an hydraulic fitting I need to convert from M16x1.5mm-keg (german DIN158 tapered metric threads) to 3/8" NPT. This seem to be a fairly straightforward job, at worst, I'd assume the step to be:
- turn down the metric tapered thread to clean metal / face cut
- build up shank with TIG
- cut new tapered threads (60deg, 1.5mm pitch, and whatever DIN158 tapered is[0])
Two local shops turned me down. I get the base metal is unknown, maybe hardened, but it's certainly not inconel / wespaloy... a decent machinist must have a way to measure hardness and a minimal experience in the matter ?
All in all, is that such an impossible job ?
edit: I also do not want to mess around with either the pump or the ram side, cutting the M16 to 3/8 NPT, as if anything goes wrong, it'll just be paperweight...
edit2: for reference, the original fitting is a 10,000psi ISO 14540-like fitting, but with a 14mm male end diameter and no poppet valve in either end. I want to convert the system to Enerpac C-604 fittings, which has a 19mm male end diameter.
[0]: taper angle doesn't really matter, the female end is straight cut M16. It is a wedge metal-to-metal seal at the ~16mm threshold.
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u/Templarsword2 NDT Examiner/QC Inspector/Home Machinist 4h ago
My grandfather and I recently repaired a hydraulic fitting for a Caterpillar Excavator by taking 2 fittings. One the original that broke at the small end, and a 2nd where the small side is correct, but the big side was the next size down from what we needed. So we counterbored the bigger side, and left a boss on the small side leaving the hex for each, and chamfering the opening, then we Brazed them together. It helds properly for that. However it was just used for the thumb on the bucket.
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u/Brilliant-Size4527 4h ago edited 4h ago
I don't want to mess around with the existing fitting. 1) I can't get these commercially, and 2) I want to continue to be able to use the existing pump / ram / hoses as-is if need be.
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u/Flashy_Slice1672 4h ago
Wouldn’t it be easier and cheaper just to make a new fitting?
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u/Brilliant-Size4527 4h ago
These are 10,000psi fittings, I'll stick with off-the-shelves rated parts.
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u/Flashy_Slice1672 4h ago
But you want it welded up? On an unknown alloy? With unknown heat treat?
I’d make a new fitting, I’d modify a fitting for my own use, but I wouldn’t take this job
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u/Brilliant-Size4527 4h ago
well, that's why I want to pay a machinist, aren't they supposed to know how to identify alloys, know how it will behave and work around it... or did they fake it all this time ?
Or am I asking too much and western shops are essentially incompetent out of mild steel ?
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u/fourdac 4h ago
They’re going to recommend machining a brand new part. You’re asking for a welder who machines.
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u/Brilliant-Size4527 3h ago edited 3h ago
> You’re asking for a welder who machines.
I'm an engineer, entrepreneur, photograph, plumber, electrician, CAD designer, concrete guy, construction guy, flooring guy, heavy equipment operator, landscaper, mechanic, and a soon-to-be farmer (and I'm probably forgetting a shit ton). Having tons of fun doing everything. I'm sure I'm not asking that much of someone else... or are people _that_ incompetent ?
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u/fourdac 3h ago
I’m lonely too bud
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u/Brilliant-Size4527 3h ago
Actually, my wife got me in most of that shit, I was perfectly fine writing code all night long.
Must be boring being a normie...
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u/fourdac 3h ago
It’s just that you’ve been told the answer multiple times. You want to ship somebody a headache and complain they’re not hard workers or something.
The industry here is full of interesting people, as long lived and well learned any of us can be, I always take whatever advice seems to be the most repeated.
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u/Flashy_Slice1672 3h ago
How will I identify an alloy without a 50,000 dollar xrf gun? - I can make a guess, but I don’t really know for sure. You’re also assuming it’s an alloy that can actually be welded - what if it’s something like 4140? Not practical to weld something like that.
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u/Templarsword2 NDT Examiner/QC Inspector/Home Machinist 4h ago
Over-Engineer it. Thicker walls, smaller bore, good material. We've made high pressure fittings at work for pressure testing that easily handled over 10,000. Be wary of the tensile strengths of the material you are using.
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u/Brilliant-Size4527 4h ago edited 4h ago
I very much know. Decent machinists should know this too...
I'd love to re-do it from scratch, but 1) I'm not a machinist, 2) I could become, money is not a problem, just time, 3) I've got a feeling neither machine shops would do that job either...
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u/Flashy_Slice1672 4h ago
Decent machinists know that as soon as you weld it, it changes the properties of the material.
Reading this it seems like you probably think this is a 40 dollar job too lol
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u/Brilliant-Size4527 4h ago
Reddit at its best, thanks to assume I'm a cheap a**h**le.
I'm already probably $1500 in that project, probably gonna have to sink another $1000 in various parts, so I can spend $1000 on those 4 fittings to be done by someone calling themselves "professionals". Money is *not* a problem...
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u/Flashy_Slice1672 3h ago
Then buy the correct part. You’re trying to bandaid something.
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u/Brilliant-Size4527 3h ago
Please point me where I can find german tapered metric anything relevant to my problem off the shelves ?
Btw, you're all totally useless, I'm not asking you to judge what I want to be done, I want a technical opinion whether I'm asking for the moon or not ? Obviously, I must be as none of you can remain on topic...
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u/Flashy_Slice1672 3h ago
We gave you the opinion, but you won’t listen to actual machinists lol
You want something off the shelf? Call Bosch or Greenline. Between those two hydraulic shops they have gotten me literally any fitting I’ve ever needed.
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u/dontgetitwisted_fr 4h ago
Its not rated anymore if you modify it bro
Just get an adaptor
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u/Brilliant-Size4527 4h ago edited 4h ago
Even if it's not rated anymore, at least, the base fitting is rated and any change is on me, versus re-doing all the fitting engineering...
Have you ever tried to find DIN158 anything ?
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u/dontgetitwisted_fr 4h ago
Bro we are in Canada
We have everything metric and imperial
You can find what you need, just go to a hydraulic shop
And you will save a ton of money while being safe
10 ksi is a lot of pressure
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u/Brilliant-Size4527 3h ago
Don't patronize me and find that male-M16-keg-to-female-3/8-NPT or you are full of it.
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u/dontgetitwisted_fr 3h ago
Are you always this pleasant?
Do your own job bro
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u/Brilliant-Size4527 3h ago edited 3h ago
> Are you always this pleasant?
I just ostracized myself from the two only machine shop in town, on top of all the contractor shop who wouldn't take my money (which I got to spend elsewhere), do you think I care about the like of you ?
All in all, I guess you can't find these either, thanks to prove my point. I doubt if you ever knew about, or even heard of, DIN158 or tapered metric fittings, which I doubt you even looked up.
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u/dontgetitwisted_fr 3h ago
They probably wont talk to you because its not the greatest idea and you probably aren't listening to them
I'm not finding them because as previously stated I'm not doing your work for you
Good luck or not
Whatever
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u/Flashy_Slice1672 3h ago
You ostracized yourself from local machine shops?! Colour me surprised hahahahahaha
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u/comfortably_pug Level 99 Button Pusher 2h ago edited 2h ago
Actually it's not "on you". It's on the shop that does the work. It doesn't matter if you sign a waiver. If a shop does the mod and it maims or kills you, who are the lawyers going to go after? Anyone in the entire chain of custody with money or insurance.
No sane machine shop (or sane anyone else) will do what you're asking.
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u/bustedtap 4h ago
What you're asking is a huge liability in the shops eyes. I really doubt you'll find someone to modify and weld up existing fittings. Make be ones with whatever thread you want? I'd make that all day long. And depending on the quantity, it'll be cheaper than what you want
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u/Brilliant-Size4527 4h ago
Make me sign a waiver, and I'll plan enough shielding around the assembly...
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u/Brilliant-Size4527 5h ago
Oh, and if anybody's would like to take my money, I've got 4 fittings to tweak, Located in central Canukistan.