Blueprinting custom actions...why?

[urbanrifleman]

In 1999 I bought my first custom action... I was still working at the time and had access to a complete state of art inspection dept.for a 75,000,000.00$ per year mfg.co....having had 38 years experience in the machine & R&D end of the co.I turned my action over to my shooting buddy...he spent a few hours with some very exspensive measuring equip.All in all the action was straight and square within. 0005" T.I.R ...
Bill...

My point has always been that the average gunsmith absolutely does not have access to measuring equipment that will meaure the tolerances accurately and repeatable. They are effectively measuring something with a tape measure that was made using a micrometer.

Anyone that has any experience in gauge quality requirements from the auto or aero industries can tell you that hand measuring a bunch of stuff with hand tools is a crap shoot and will be operator dependant. There is a whole portion of Six Sigma that tests the tester. Most people, even machinists are completely unaware how capable their measuring tools actually are...

They brag about hold half a thou and they are measuring with a gauge that won't hold two thou across three opeators.

 

[DaveTooley]

I have some OEM accounts. When it has to be done right I get a call. They have learned not to send things through their QC department. My work performs and functions but there is usually a long list of demerits if they involve a CMM.

 

[geo.ulrich]

Whether you call them ‘custom” or “limited production” they’re just made with better care. The big factories machine the entire action using relatively coarse cutting methods (larger feeds and depths of cut perhaps) Then they go to heat treat in large batches. Seldom are they stress relieved. So they warp.

Are you saying the custom actions do not warp, try again they can warp whether machined prior to or after heat treating. any cut either releases or induces stress in metal...

 

[riflewoman]

Are you saying the custom actions do not warp, try again they can warp whether machined prior to or after heat treating. any cut either releases or induces stress in metal...

Nope, the customs can warp. But the warpage certainly won’t be as drastic.

Most high grade material bought nowadays comes from the mill stress relieved already. Presuming good care in the machining, the induced stresses can be minimized. So with either a final heat treat or a stress relief after machining a pre-hardened billet, the warpage should be within 0.001 TIR.

Regardless of what the actual warpage really is, my position has always been that the vast majority of gunsmiths and working machinists do not have the equipment or knowledge to even measure how out of true the action is. To straighten an action you need to have the skills of and equipment of an honest-to-god toolmaker. Last time I looked the latter are getting almost as scarce as unicorns.

 

[swd]

I believe a unicorn posted just above yours.

 

[hogpatrol]

Just curious, any custom action manufacturers using CMM for QC? If so, on every action?

 

[msinc]

Do corrective machine work on an expensive custom action???? I hope not. If I have to wash dishes before I put them in the dishwasher to make sure they come out clean......then I bought the wrong dishwasher.

 

[Tommie]

If I have to wash dishes before I put them in the dishwasher to make sure they come out clean......then I bought the wrong dishwasher.

Ladies and Gentlemen:
Quote of the day.

 

[Evan]

Just curious, any custom action manufacturers using CMM for QC? If so, on every action?

This is the lesson I have to teach every fresh engineer that comes in under me. You can throw +/-0.001 on a print, slam down some tight concentricity or parallelism spec's, but unless you pay for CMM inspection on every part, you and the machinist won't know if it was actually hit or not.

 

[geo.ulrich]

Nope, the customs can warp. But the warpage certainly won’t be as drastic.

Most high grade material bought nowadays comes from the mill stress relieved already. Presuming good care in the machining, the induced stresses can be minimized. So with either a final heat treat or a stress relief after machining a pre-hardened billet, the warpage should be within 0.001 TIR.

Regardless of what the actual warpage really is, my position has always been that the vast majority of gunsmiths and working machinists do not have the equipment or knowledge to even measure how out of true the action is. To straighten an action you need to have the skills of and equipment of an honest-to-god toolmaker. Last time I looked the latter are getting almost as scarce as unicorns.

Ah yes the new materials, hate to tell you but stress relieved from the mills has been around before I started in the trade in the mid 70's along with prehard materials. so with a stress relieved piece of stock then you machine it you are either releasing or imparting stress either way its there and when you remove part from fixture it will move. I don't have any idea what you've been checking but if all are within .001 I will be very surprised some are good but awhole bunch are not. and this isn't even discussing the issues with the ASSEMBLY. I will agree with the run of the mill barrel fitter no he can't tell you even where to start. start with stress relieved rough cut heat treat re stress relieve then finish will keep it about as good as it can get. or check what you get and have it fixed . I have been machinist since mid 70's, toolmaker since early 80's and a gage maker since 89.... whats beyond unicorns....

 

[geo.ulrich]

This is the lesson I have to teach every fresh engineer that comes in under me. You can throw +/-0.001 on a print, slam down some tight concentricity or parallelism spec's, but unless you pay for CMM inspection on every part, you and the machinist won't know if it was actually hit or not.

or if you are making the same parts which action mfgr's are just make inspection fixtures and gages, parts where being checked long before cmm's , funny thing the govt. wouldn't allow cmm for inspection until not so long ago....

 

[hogpatrol]

This is the lesson I have to teach every fresh engineer that comes in under me. You can throw +/-0.001 on a print, slam down some tight concentricity or parallelism spec's, but unless you pay for CMM inspection on every part, you and the machinist won't know if it was actually hit or not.

I loved working with new M.E.s. If you couldn't dazzle them with brilliance, you could usually baffle them with bovine fecal matter. It was rare that you didn't get one that was totally clueless to machine work.

 

[hogpatrol]

or if you are making the same parts which action mfgr's are just make inspection fixtures and gages, parts where being checked long before cmm's , funny thing the govt. wouldn't allow cmm for inspection until not so long ago....

That's curious about the government. The last CMM I ran, it checked in microns and this was sheet metal auto sub assemblies. Why it was to that point, I'll never understand.

 

[geo.ulrich]

yes the mauser ones I used from the mid 80's had a resolution or decimals .00000000 or so they said, it was sold off within 6 months as not being a reliable enough way to check. I'm not saying they do not work its in the operator I have watched some that beeped off nice and slow others run around parts like they are playing shuffle board or playing a video game...

 

[Evan]

or if you are making the same parts which action mfgr's are just make inspection fixtures and gages, parts where being checked long before cmm's , funny thing the govt. wouldn't allow cmm for inspection until not so long ago....

I agree, but I'm in R&D, so CMM inspection is usually cheaper than bespoke fixturing for quantities never exceeding 5. But here again, we circle back to the operator. A CMM will lie to you and it takes someone smart to make sure they're getting real, repeatable measurements of the part.

I have this same concern with sorting bullets by base to ogive with a pair of calipers and a comparator. I tried it for amusement: measuring the same ten bullets over and over across a couple days. I never got them sorted conclusively and decided that it would take more specialized equipment than calipers and an aluminum comparator of unknown uniformity to do. How many folks here are blowing smoke up their backsides telling themselves they can sort bullets into 0.0005", or even 0.001" bins! Did they try remeasuring those bullets the following day to see if the sorting was still the same?

The real lesson for the new engineers to learn is to use their brains, and create something that doesn't need those types of tolerances. More often than not, a clever solution exists that has broader tolerances and doesn't create an ungodly scrap rate to get the "perfect" part they had dreamed up.

 

[riflewoman]

I agree, but I'm in R&D, so CMM inspection is usually cheaper than bespoke fixturing for quantities never exceeding 5. But here again, we circle back to the operator. A CMM will lie to you and it takes someone smart to make sure they're getting real, repeatable measurements of the part.

The real lesson for the new engineers to learn is to use their brains, and create something that doesn't need those types of tolerances. More often than not, a clever solution exists that has broader tolerances and doesn't create an ungodly scrap rate to get the "perfect" part they had dreamed up.

Yup... been there with the engineers in my design team. My normal markups were to loosen positionals to .028 and surfaces to .030. If they wanted tighter they had to justify it.

As for CMMs, never worked with any but they’re now so prevalent it’s hard to justify bespoke tooling. Finding a good operator on the other hand...more unicorns. And as for CMMs now being acceptable to the government. So far as I know, the FAA refuses to accept Finite Element Modeling of aircraft structure as “Stress Analysis”. Perfectly fine to use for developing internal loads however.

 

[geo.ulrich]

it would be for D.O.D work, oops Boeing defense uses them now so.....

 

[riflewoman]

Well, the Navy uses them, so...

https://www.navsea.navy.mil/Home/Wa...na/What-We-Do/Measurement-Science-Department/

 

[tomswede]

Yup... been there with the engineers in my design team. My normal markups were to loosen positionals to .028 and surfaces to .030. If they wanted tighter they had to justify it.

As for CMMs, never worked with any but they’re now so prevalent it’s hard to justify bespoke tooling. Finding a good operator on the other hand...more unicorns. And as for CMMs now being acceptable to the government. So far as I know, the FAA refuses to accept Finite Element Modeling of aircraft structure as “Stress Analysis”. Perfectly fine to use for developing internal loads however.

Not sure what your company makes but .028 and .030 is pretty liberal tolerances.
But as has been stated the trick to make good consistent parts is in tooling setup and sequence of operations. Inspections has to be made, but inspecting quality in is a bad idea.
I have 35 years in aircraft engine and gas turbine design, our tolerances are tighter and the FAA has accepted FEM analysis as long as I have been in the business. There is of course also actual engine tests.

 

[dcali]

Alex, the funny thing is try and get one to say what the tolerances are they are working too ..theres a big jump $$$$$ from .001 to .0001

When I was in school, the rule of thumb was that each decimal place was good for a 10x increase in cost over the last one. I’ve seen nothing in the 20 years since to change my mind on that.