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automotive engine boring on a mill
I want to get into the hobby of machinist;automotive machinery to be
exact. I have six kids so I am on a really tight budget. My question is, can I bore automotive engine blocks on a large grizzly mill? I have read alot of posts that discourage against this but how difficult could it be? I am not sure of what particular modle to purchase but it will be pretty heavy-duty. I can buy a very stirdy jig to hold a engine block from one of the many companies which now sell machines which are similuar to a mill. The only problem I can see, is what type of boring bit to use and how to attach it? Is a R8 end holder sturdy engough? It must be sturdy enough to bore hole up to six inches. Any coments? |
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I want to get into the hobby of machinist;automotive machinery to be
exact. I have six kids so I am on a really tight budget. My question is, can I bore automotive engine blocks on a large grizzly mill? I Sounds like a troll, but I'll bite either way. Aren't most engines rough bored then honed? I'd think that with enough hone action, you might be able to bore it on a lathe.  -- Joe - V#8013 - '86 VN750 - joe @ yunx .com Northern, NJ Ride a Motorcycle? Ask me about "The Ride" http://www.youthelate.com/the_ride.htm Born once - Die twice. Born twice - Die only once. Your choice... Have unwanted music CDs or DVDs of any type? I can use them for our charity. eMail me privately for details. Donation receipts available. |
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#3
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Dont waste your time on this idea- automotive boring machines are very
specialized- your best bet is to cruise around various automotive machine shops and try to find a used portable boring bar- these clamp to the block surface to do 1 hole at a time and can even bore a hole with the block in the car. Then you need a hone ( not a glaze breaker) For hobby work you might get the basics for under 1000.00 to get started. I want to get into the hobby of machinist;automotive machinery to be exact. I have six kids so I am on a really tight budget. My question is, can I bore automotive engine blocks on a large grizzly mill? I have read alot of posts that discourage against this but how difficult could it be? I am not sure of what particular modle to purchase but it will be pretty heavy-duty. I can buy a very stirdy jig to hold a engine block from one of the many companies which now sell machines which are similuar to a mill. The only problem I can see, is what type of boring bit to use and how to attach it? Is a R8 end holder sturdy engough? It must be sturdy enough to bore hole up to six inches. Any coments? |
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"Anthony" As for the other poster on the hone...junk bore to start with on a hone....junk bore after honing... ???????? -- Anthony |
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#6
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"Ahernwill" wrote in message nk.net... "Anthony" As for the other poster on the hone...junk bore to start with on a hone....junk bore after honing... ???????? Honing isn't exactly a "high rate of material removal" process. Nasty boring jobs usually leave reasonably deep grooves in the bore that I wouldn't want to try to remove with a real (Sunnen) honing machine, especially on a 6" diameter cylinder. Of course, I've never done it so I could be wrong. Regards, Robin |
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nattydreadlocks wrote: I want to get into the hobby of machinist;automotive machinery to be exact. I have six kids so I am on a really tight budget. My question is, can I bore automotive engine blocks on a large grizzly mill? I have read alot of posts that discourage against this but how difficult could it be? I am not sure of what particular modle to purchase but it will be pretty heavy-duty. I can buy a very stirdy jig to hold a engine block from one of the many companies which now sell machines which are similuar to a mill. The only problem I can see, is what type of boring bit to use and how to attach it? Is a R8 end holder sturdy engough? It must be sturdy enough to bore hole up to six inches. Any coments? IF you want to do boring get a horizontal mill, the bigger the better. They are all over the place for practically nothing. I would look for one with a 50 taper since tooling is easy to come by. If your lucky you will find a horizontal with a nuckle head, or two axis swivel head that will give you vertical capabilities too, and all those mills have automatic feed. John |
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When I was a kid I bored both single cylinder Briggs & Stratton and
four cylinder Crosleys on my Dad's 11" South Bend. It was quite an exercise as the boring bar he had was simply a big stout boring bar with not calibrations. You adjusted the bar by loosening the tool and tapping it gently then made a test cut. Usually took a couple of evenings to do a Crosley to +/-.0005. I have some Crosley engines to do right now and you can bet I will be doing them on a Bridgeport type mill. They don't work well with the standard automotive boring bars as they have nondetachable heads and you have to have a rigid downstop. BTW: To the fellow that suggested you use a boring bar sysem that locates on the top deck of the engine, NO WAY! Good boring machines locate on the crankshaft centerline. To answer the original poster's question; a vertical mill is not the machine to bore engines on. Leigh at MarMachine |
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Remember the guy is a low budget hobbyist- every automotive machine shop has
the deck mount boring bars for special jobs and for any production automotive work they are fine- Indexing off the crank is only necessary for high performance engines- Don't forget that most mills dont have a table designed to hold a block and the required accessories, not to mention the difficulty of lifting the block into place- specialized machines have large non- moveable tables and open fronts so blocks can be slid into position from rolling carts. This is all in relation to automotive engines- lawn mowers, go carts and little stuff like Crosleys are a different story. To the guy who posted the gibberish about honing, you always rough bore and hone to fit. "Leigh Knudson" When I was a kid I bored both single cylinder Briggs & Stratton and four cylinder Crosleys on my Dad's 11" South Bend. It was quite an exercise as the boring bar he had was simply a big stout boring bar with not calibrations. You adjusted the bar by loosening the tool and tapping it gently then made a test cut. Usually took a couple of evenings to do a Crosley to +/-.0005. I have some Crosley engines to do right now and you can bet I will be doing them on a Bridgeport type mill. They don't work well with the standard automotive boring bars as they have nondetachable heads and you have to have a rigid downstop. BTW: To the fellow that suggested you use a boring bar sysem that locates on the top deck of the engine, NO WAY! Good boring machines locate on the crankshaft centerline. To answer the original poster's question; a vertical mill is not the machine to bore engines on. Leigh at MarMachine |
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Subject: automotive engine boring on a mill
From: Anthony Date: 05/12/04 14:08 GMT Standard Time Message-id: (nattydreadlocks) wrote in . com: I want to get into the hobby of machinist;automotive machinery to be exact. I have six kids so I am on a really tight budget. My question is, can I bore automotive engine blocks on a large grizzly mill? I have read alot of posts that discourage against this but how difficult could it be? I am not sure of what particular modle to purchase but it will be pretty heavy-duty. I can buy a very stirdy jig to hold a engine block from one of the many companies which now sell machines which are similuar to a mill. The only problem I can see, is what type of boring bit to use and how to attach it? Is a R8 end holder sturdy engough? It must be sturdy enough to bore hole up to six inches. Any coments? Hehe...not a chance in hell... Ya...you *can* do it.....but the bore will be absolute junk, quality- wise. R8 doesn't have the ridgity needed to bore the block to the quality requirements needed for an engine. As for the other poster on the hone...junk bore to start with on a hone....junk bore after honing... Provided enough material is honed out to remove all tooling marks it matters not a jot what the quality of the original bore is like. It can have 4 thou deep chatter marks as long as you hone out 8 thou on diameter. Not that anyone with any sense would want to do that. I have in fact bored engine blocks on my Bridgeport mill. I made a boring bar 8" long and 2" diameter that clamped directly to the quill nose and became an extension of it so as to bypass the horribly flimsy R8 bit. Even so it wasn't nearly rigid enough to bore a block accurately with although much of that is play in the quill itself. Mills are just not designed to be as rigid as jig borers. There wasn't enough travel on the quill which meant boring by winding the knee up by hand. It was quite fun in a masochistic sort of way, standing there trying to wind the knee handle at a constant rate for several minutes at a time. After experimentation with speeds, feeds and tool tip profile I got chatter down to a marvellously awful 2 thou or so which meant honing at least 5 thou out on diameter. However most of that was just the crests of the chatter marks so it wasn't all solid material. With a coarse stone in the Delapena honing tool the bulk of the material came out fairly fast and then the last half thou or so was done on a finer stone. It was a bloody awful way of boring blocks but saved me about as much time driving each block twice each way to someone else to get it done as it took to bore them myself. Now I have a Wandess boring bar (clamp on the block type) which is wonderful and leaves a finish so fine you could just about run a piston in it. In fact when that machine was designed the aim actually was to bore so fine you didn't need to hone. Of course without cross hatch honing marks a bore never works properly but back in the 40s the aim was to get engines back out on the streets as fast as possible and carry on fighting off the Germans. So no you can't sensibly bore out blocks on any kind of mill unless you are prepared to also spend ages honing them to finish size. -- Dave Baker - Puma Race Engines (www.pumaracing.co.uk) |
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#11
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Subject: automotive engine boring on a mill
From: (Leigh Knudson) Date: 06/12/04 02:47 GMT Standard Time Message-id: When I was a kid I bored both single cylinder Briggs & Stratton and four cylinder Crosleys on my Dad's 11" South Bend. It was quite an exercise as the boring bar he had was simply a big stout boring bar with not calibrations. You adjusted the bar by loosening the tool and tapping it gently then made a test cut. Usually took a couple of evenings to do a Crosley to +/-.0005. I have some Crosley engines to do right now and you can bet I will be doing them on a Bridgeport type mill. They don't work well with the standard automotive boring bars as they have nondetachable heads and you have to have a rigid downstop. BTW: To the fellow that suggested you use a boring bar sysem that locates on the top deck of the engine, NO WAY! Good boring machines locate on the crankshaft centerline. I'm not aware of any normal boring machine that locates on a crank centreline. Either the block stands on its sump face on the machine table or the machine bolts to the top of the block. V engines can sometimes be tricky to jig up if there is no readily available flat face to mount on so they can need a jig that bolts into the crank saddles. That isn't a function of the boring machine though. It's a function of the jig that bolts to the machine table that is hopefully true to the boring head. Provided either of those faces is as true to the crank centreline as needed then both methods work fine. I always put a light skim on the head gasket face before using my bolt-on boring machine to make sure the head face is true. There's no guarantee that a sump face will be true either though. However it's a crock of **** to think that tiny errors in the bore's perpendicularity or centrality to the crank make any real difference to an engine's power output. In fact if the error in the original bore was very big you'd never be able to correct it anyway without going to a very large overbore size. -- Dave Baker - Puma Race Engines (www.pumaracing.co.uk) |
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Good reply, Leigh! Thanks on behalf of Bridgie owners everywhere.
Bob Swinney "Leigh Knudson" wrote in message om... When I was a kid I bored both single cylinder Briggs & Stratton and four cylinder Crosleys on my Dad's 11" South Bend. It was quite an exercise as the boring bar he had was simply a big stout boring bar with not calibrations. You adjusted the bar by loosening the tool and tapping it gently then made a test cut. Usually took a couple of evenings to do a Crosley to +/-.0005. I have some Crosley engines to do right now and you can bet I will be doing them on a Bridgeport type mill. They don't work well with the standard automotive boring bars as they have nondetachable heads and you have to have a rigid downstop. BTW: To the fellow that suggested you use a boring bar sysem that locates on the top deck of the engine, NO WAY! Good boring machines locate on the crankshaft centerline. To answer the original poster's question; a vertical mill is not the machine to bore engines on. Leigh at MarMachine |
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Do you know Dodge Reidy? He's local engine builder (San Francisco Bay
Area)that's done a lot with Crosleys, especially with vintage race motors. I suspect the Crossley world is pretty small. Peter "Leigh Knudson" wrote in message om... When I was a kid I bored both single cylinder Briggs & Stratton and four cylinder Crosleys on my Dad's 11" South Bend. It was quite an exercise as the boring bar he had was simply a big stout boring bar with not calibrations. You adjusted the bar by loosening the tool and tapping it gently then made a test cut. Usually took a couple of evenings to do a Crosley to +/-.0005. I have some Crosley engines to do right now and you can bet I will be doing them on a Bridgeport type mill. They don't work well with the standard automotive boring bars as they have nondetachable heads and you have to have a rigid downstop. BTW: To the fellow that suggested you use a boring bar sysem that locates on the top deck of the engine, NO WAY! Good boring machines locate on the crankshaft centerline. To answer the original poster's question; a vertical mill is not the machine to bore engines on. Leigh at MarMachine |
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Do you know Dodge Reidy?
Naw, not I. I'm not in to Crossleys. I was just glad to hear Leigh say that vertical mills are suitable for engine boring, etc. Bob Swinney "Peter Grey" wrote in message news 
He's local engine builder (San Francisco BayArea)that's done a lot with Crosleys, especially with vintage race motors. I suspect the Crossley world is pretty small. Peter "Leigh Knudson" wrote in message om... When I was a kid I bored both single cylinder Briggs & Stratton and four cylinder Crosleys on my Dad's 11" South Bend. It was quite an exercise as the boring bar he had was simply a big stout boring bar with not calibrations. You adjusted the bar by loosening the tool and tapping it gently then made a test cut. Usually took a couple of evenings to do a Crosley to +/-.0005. I have some Crosley engines to do right now and you can bet I will be doing them on a Bridgeport type mill. They don't work well with the standard automotive boring bars as they have nondetachable heads and you have to have a rigid downstop. BTW: To the fellow that suggested you use a boring bar sysem that locates on the top deck of the engine, NO WAY! Good boring machines locate on the crankshaft centerline. To answer the original poster's question; a vertical mill is not the machine to bore engines on. Leigh at MarMachine |
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I want to get into the hobby of machinist;automotive machinery to be
exact. I have six kids so I am on a really tight budget. My question is, can I bore automotive engine blocks on a large grizzly mill? I have read alot of posts that discourage against this but how difficult could it be? I am not sure of what particular modle to purchase but it will be pretty heavy-duty. I can buy a very stirdy jig to hold a engine block from one of the many companies which now sell machines which are similuar to a mill. The only problem I can see, is what type of boring bit to use and how to attach it? Is a R8 end holder sturdy engough? It must be sturdy enough to bore hole up to six inches. Any coments? In addition to the other drawbacks to using a BP clone that have been mentioned, one other BIG drawback is that most BP clones only have 5" of travel to the spindle. Mike |
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Subject: automotive engine boring on a mill
From: Anthony Date: 06/12/04 23:51 GMT Standard Time Message-id: (Dave Baker) wrote in : Provided enough material is honed out to remove all tooling marks it matters not a jot what the quality of the original bore is like. It can have 4 thou deep chatter marks as long as you hone out 8 thou on diameter. Not that anyone with any sense would want to do that. Sure...but what *quality* of bore do you have? What is the roundness and straightness? Yes....it might work....but for how long? What kind of blowby and ring wear are you going to see? A hone, to some extent, is going to follow the bore that exists. This is true of most any finishing operation. The quality of the previous operations will almost always influence the quality of the finish operations, to some degree. It is a matter of to what precision you wish to measure, and how accurate you wish the final product to be. The whole point of rigid stone honing is that it doesn't follow imperfections in the original bore. The most it follows is the general direction of that bore. A good honing machine removes all taper, ovality and lack of straightness. Provided sufficient material is left in place to allow a perfect cylinder to be created after the original boring operation it makes no difference what quality that boring operation was done to. As for measuring equipment, my own bore gauge is a Mercer dial bore gauge reading to 0.0001". Most commercial engine reconditioning operations use 0.001" gauges which are adequate for the general -0/+0.001" tolerance on piston fitment. My work needs to be infinitely more precise, and is! I have two honing systems. A Snap-On 5" stone system which is best for achieving perfect bore straightness because the stones are longer and a Delapena 4" stone system which is better for removing taper from the bottom of bores where the crank saddles prevent you "through honing" as far as you would ideally like. Choice of stone grit and speed and feed then lead to the perfect surface finish and cross hatch angle. I have to conclude that if you think that honing can't create a perfect bore regardless of imperfections in the boring operation then this isn't an area of machining that you have actually been involved in. In fact I'll ask. Have you ever actually used a professional rigid stone engine cylinder honing system? -- Dave Baker - Puma Race Engines (www.pumaracing.co.uk) |
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In article , Dave Baker says...
The whole point of rigid stone honing is that it doesn't follow imperfections in the original bore. Sunnen. Dave's right. Jim -- ================================================== please reply to: JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com ================================================== |
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"Dave Baker" wrote in message ... As for measuring equipment, my own bore gauge is a Mercer dial bore gauge reading to 0.0001". Most commercial engine reconditioning operations use 0.001" gauges which are adequate for the general -0/+0.001" tolerance on piston fitment. My work needs to be infinitely more precise, and is! Buzz. No. Dave. You need to be careful as you are walking a fine line here. Some of us actually make mass produced cars, pieces of mass produced cars, or the things that make the mass produced cars. To scratch the surface of your statement above, your Mercer dial bore gauge is as accurate as is required to measure a bore who's diameter (in only one plane) needs to be within .001". If you wanted to make the bore to within ..0001", your bore gauge would not be accurate enough. Also, your bore gauge is _incapable_ of telling you if your bore is *correct*. GD&T and process capability (Cp and Cpk) come into play big time, just off the top of my head. I have to conclude that if you think that honing can't create a perfect Buzz. That word doesn't exist in automotive manufacturing (and if it did, I'd be walking to work). Regards, Robin |
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"Robert Swinney" wrote in message
... Good reply, Leigh! Thanks on behalf of Bridgie owners everywhere. Bob Swinney "Leigh Knudson" wrote in message om... When I was a kid I bored both single cylinder Briggs & Stratton and four cylinder Crosleys on my Dad's 11" South Bend. It was quite an exercise as the boring bar he had was simply a big stout boring bar with not calibrations. You adjusted the bar by loosening the tool and tapping it gently then made a test cut. Usually took a couple of evenings to do a Crosley to +/-.0005. I have some Crosley engines to do right now and you can bet I will be doing them on a Bridgeport type mill. They don't work well with the standard automotive boring bars as they have nondetachable heads and you have to have a rigid downstop. BTW: To the fellow that suggested you use a boring bar sysem that locates on the top deck of the engine, NO WAY! Good boring machines locate on the crankshaft centerline. To answer the original poster's question; a vertical mill is not the machine to bore engines on. Leigh at MarMachine Holy cow, you have some Hot-shots? The stamped ones, or cast? We've got to see some photos of this, Leigh. I saw drawings from the early '20s of some pretty interesting setups with a 4-cyl. engine clamped to a slotted cross-slide, and I've always wanted to see someone do it. Ed Huntress |
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#22
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"jim rozen" wrote in message
... In article , Dave Baker says... The whole point of rigid stone honing is that it doesn't follow imperfections in the original bore. Sunnen. Dave's right. FWIW, my ISP has been screwing around and I've lost days worth of messages, but Sunnen was my pet subject for a couple of years, and the hones they make today (non-automotive as well as automotive) make their own way in a hole, pretty much, and often are used to make near-perfect cylinders in crappy machined bores, in OEM production. They can straighten a bore that's cockeyed as hell. They're amazing. I presume this is what Dave said, in which case, 'sorry for being redundant. g Ed Huntress |
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On Sun, 05 Dec 2004 21:03:22 -0500, john wrote:
nattydreadlocks wrote: I want to get into the hobby of machinist;automotive machinery to be exact. I have six kids so I am on a really tight budget. My question is, can I bore automotive engine blocks on a large grizzly mill? I have read alot of posts that discourage against this but how difficult could it be? I am not sure of what particular modle to purchase but it will be pretty heavy-duty. I can buy a very stirdy jig to hold a engine block from one of the many companies which now sell machines which are similuar to a mill. The only problem I can see, is what type of boring bit to use and how to attach it? Is a R8 end holder sturdy engough? It must be sturdy enough to bore hole up to six inches. Any coments? IF you want to do boring get a horizontal mill, the bigger the better. They are all over the place for practically nothing. I would look for one with a 50 taper since tooling is easy to come by. If your lucky you will find a horizontal with a nuckle head, or two axis swivel head that will give you vertical capabilities too, and all those mills have automatic feed. John I'm going to second the motion for this idea. Not something you want in a tiny garage, but if you have the space it's the way to go..cheap, beefy, and suitable to the task. I have seen pictures of V8 diesel engine blocks being machined in a bed-type 50 taper horizontal (it looked like anyway). The setup looked like it was setup for boring-IIRC, the block was mounted vertically on the bell-housing deck, and it was setting on a rotary table. With that setup, you could deck it and do all 8 bores in one set-up. The crank center line would be easy to pick up by mounting the crank bores over a spud. The disadvantage with a purpose built automotive boring machine is just that- you can only do one thing with them, but a mill can earn its keep in other ways. Disclaimer-just my opinion, my expertise is not in automotive machining. Brent. |
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#24
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Dave sez, smugly: "I have to conclude that if you think that honing can't
create a perfect bore regardless of imperfections in the boring operation then this isn't an area of machining that you have actually been involved in. In fact I'll ask. Have you ever actually used a professional rigid stone engine cylinder honing system?" So Dave! Whyn't you make up one of your Cockney stories to go with this? Bob Swinney "Dave Baker" wrote in message ... Subject: automotive engine boring on a mill From: Anthony Date: 06/12/04 23:51 GMT Standard Time Message-id: (Dave Baker) wrote in : Provided enough material is honed out to remove all tooling marks it matters not a jot what the quality of the original bore is like. It can have 4 thou deep chatter marks as long as you hone out 8 thou on diameter. Not that anyone with any sense would want to do that. Sure...but what *quality* of bore do you have? What is the roundness and straightness? Yes....it might work....but for how long? What kind of blowby and ring wear are you going to see? A hone, to some extent, is going to follow the bore that exists. This is true of most any finishing operation. The quality of the previous operations will almost always influence the quality of the finish operations, to some degree. It is a matter of to what precision you wish to measure, and how accurate you wish the final product to be. The whole point of rigid stone honing is that it doesn't follow imperfections in the original bore. The most it follows is the general direction of that bore. A good honing machine removes all taper, ovality and lack of straightness. Provided sufficient material is left in place to allow a perfect cylinder to be created after the original boring operation it makes no difference what quality that boring operation was done to. As for measuring equipment, my own bore gauge is a Mercer dial bore gauge reading to 0.0001". Most commercial engine reconditioning operations use 0.001" gauges which are adequate for the general -0/+0.001" tolerance on piston fitment. My work needs to be infinitely more precise, and is! I have two honing systems. A Snap-On 5" stone system which is best for achieving perfect bore straightness because the stones are longer and a Delapena 4" stone system which is better for removing taper from the bottom of bores where the crank saddles prevent you "through honing" as far as you would ideally like. Choice of stone grit and speed and feed then lead to the perfect surface finish and cross hatch angle. Dave Baker - Puma Race Engines (www.pumaracing.co.uk) |
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"Anthony" wrote in message ... We hold bore diameter tolerances of +/- 2 microns and roundness to 1.5 microns during boring of pistons, I'm not sure who your customers are, but do different customers ask for different tolerances on those parts? I find it interesting to see the difference between the quality requirements between the various OEMs and Tier 1s. Regards, Robin |
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"Gene Kearns" wrote in message news  On 4 Dec 2004 19:42:10 -0800, This is about the minimum you are going to be looking for: http://www.jamisonequipment.com/item...?Product=10700 If you can't afford the right equipment, I can *assure* you that you won't be able to compensate people for the scrap blocks... You are right that's the one to get, also it lines up to the crank center line. Kwick way (Spelling?) makes one kinda like it to. |
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#27
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Subject: automotive engine boring on a mill
From: "Robin S." Date: 07/12/04 03:12 GMT Standard Time Message-id: "Dave Baker" wrote in message ... As for measuring equipment, my own bore gauge is a Mercer dial bore gauge reading to 0.0001". Most commercial engine reconditioning operations use 0.001" gauges which are adequate for the general -0/+0.001" tolerance on piston fitment. My work needs to be infinitely more precise, and is! Buzz. No. Dave. You need to be careful as you are walking a fine line here. Some of us actually make mass produced cars, pieces of mass produced cars, or the things that make the mass produced cars. To scratch the surface of your statement above, your Mercer dial bore gauge is as accurate as is required to measure a bore who's diameter (in only one plane) needs to be within .001". If you wanted to make the bore to within .0001", your bore gauge would not be accurate enough. Also, your bore gauge is _incapable_ of telling you if your bore is *correct*. GD&T and process capability (Cp and Cpk) come into play big time, just off the top of my head. I have to conclude that if you think that honing can't create a perfect Buzz. That word doesn't exist in automotive manufacturing (and if it did, I'd be walking to work). Buzz. Please don't preface your comments with buzz again. It comes across as horribly pretentious. I'm not sure why you think you need to measure anything with a machine capable of ten times the resolution of the dimension you are seeking to measure. I don't claim that my Mercer will measure to 0.0001" repeatably but it will measure to 0.0002" or 0.0003" repeatably. It's certainly within the realms where temperature variations make a bigger difference to the bore size than the accuracy of the honing operation. I have to let blocks stand overnight after honing to be absolutely sure of the final dimension. Every time you use a micrometer calibrated in tenths do you just ignore the tenths and call it to the nearest thou? I'm damn sure no one else does. Yes there's no such thing as a perfect bore in absolute terms but that's not what I or anyone else mean. Perfect means perfect in terms of the tolerances that empirical testing has found to be insignificant in altering the component's performance. I'm more than happy that what I produce far exceeds the accuracy requirements of OE production and matches the best that any other race engine builder in my line of work produces. As for OE tolerances, they seem to have gone to hell in a handbasket recently. 30 years ago Ford used to grade their pistons in intervals of a few tenths to match the measured bore size as blocks came off the production line. I measured a couple of brand new 2 litre Zetec engine blocks some time ago and they had about 1 thou difference between the smallest and largest bores on the same block and about the same error on taper and ovality. I'd expect better than that from a lawnmower engine made in India. However, engines are amazingly tolerant of bore errors. Piston rings, once they have bedded in, cope happily with quite large ovality and taper errors and frankly most of the stuff you read about the importance of blueprinting engines is pure bull****. It's fine to aim for in theory but makes sod all difference in practice. Even if you work to the finest tolerances the engine does its best to ignore your work when it's running. Bores, cranks, rings vibrate like the bloody clappers when engines are going full tilt at 7k plus rpm and your tenths tolerance on the original machining are swamped by the thous of movement in the components when they are under load. -- Dave Baker - Puma Race Engines (www.pumaracing.co.uk) |
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"Robin S." wrote in
news
I'm not sure who your customers are, but do different customers ask for different tolerances on those parts? I find it interesting to see the difference between the quality requirements between the various OEMs and Tier 1s. Regards, Robin Yes. The tolerances do change from customer to customer. They also change due to the design of the engine and piston. There is a complete book of 'standard' or default tolerances to go along with that. From what I have seen, the Tier 1's are usually held to a considerably tighter quality standard than are in-house products. This is not true of all of the OEM's... -- Anthony You can't 'idiot proof' anything....every time you try, they just make better idiots. Remove sp to reply via email |
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"Robin S." wrote in
news 
"Dave Baker" wrote in message ... As for measuring equipment, my own bore gauge is a Mercer dial bore gauge reading to 0.0001". Most commercial engine reconditioning operations use 0.001" gauges which are adequate for the general -0/+0.001" tolerance on piston fitment. My work needs to be infinitely more precise, and is! Buzz. No. Dave. You need to be careful as you are walking a fine line here. Some of us actually make mass produced cars, pieces of mass produced cars, or the things that make the mass produced cars. To scratch the surface of your statement above, your Mercer dial bore gauge is as accurate as is required to measure a bore who's diameter (in only one plane) needs to be within .001". If you wanted to make the bore to within .0001", your bore gauge would not be accurate enough. Also, your bore gauge is _incapable_ of telling you if your bore is *correct*. GD&T and process capability (Cp and Cpk) come into play big time, just off the top of my head. I have to conclude that if you think that honing can't create a perfect Buzz. That word doesn't exist in automotive manufacturing (and if it did, I'd be walking to work). Regards, Robin Agreed. -- Anthony You can't 'idiot proof' anything....every time you try, they just make better idiots. Remove sp to reply via email |
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"Dave Baker" wrote in message ... Buzz. Please don't preface your comments with buzz again. It comes across as horribly pretentious. Yes, you're right. But then I seem to remember a history. Every time you use a micrometer calibrated in tenths do you just ignore the tenths and call it to the nearest thou? I'm damn sure no one else does. Certainly not. You have a tolerance of +/- .001" The component is actually out by .0009" Is your instrument (which measures to within .001") going to tell you if the part is in spec? Simple example but so very relavant. I understand what you're saying however. The real issue is that we come from different worlds. As for OE tolerances, they seem to have gone to hell in a handbasket recently. 30 years ago Ford used to grade their pistons in intervals of a few tenths to match the measured bore size as blocks came off the production line. I measured a couple of brand new 2 litre Zetec engine blocks some time ago and they had about 1 thou difference between the smallest and largest bores on the same block and about the same error on taper and ovality. I'd expect better than that from a lawnmower engine made in India. Well, it WAS a Ford.... However, engines are amazingly tolerant of bore errors. Piston rings, once they have bedded in, cope happily with quite large ovality and taper errors and frankly most of the stuff you read about the importance of blueprinting engines is pure bull****. It's fine to aim for in theory but makes sod all difference in practice. Even if you work to the finest tolerances the engine does its best to ignore your work when it's running. Bores, cranks, rings vibrate like the bloody clappers when engines are going full tilt at 7k plus rpm and your tenths tolerance on the original machining are swamped by the thous of movement in the components when they are under load. While that may be true, I expect my Toyota's engine and transmission to last 300,000km. Small errors tend to come out over milllions or billions of cycles (I'm not going to do the math). Regards, Robin |
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Subject: automotive engine boring on a mill
From: Anthony Date: 08/12/04 00:47 GMT Standard Time Message-id: (Dave Baker) wrote in : I'm not sure why you think you need to measure anything with a machine capable of ten times the resolution of the dimension you are seeking to measure. Because that is precisely what just about any nationally/internationally recognized quality standards require. Your gauge must have an R&R of less than 10% of the tolerance you are measuring, and this must be documented and certified yearly. (Just out of curiosity, when was the last time your gauge was certified?) snip all the rest This thread is about the boring and honing of engine blocks for engine reconditioning. I don't know why you and Robin keep trying to drag it into an argument about production line metrology which has nothing to do with the needs of a man trying to bore and hone the one engine he has in front of him at the time so that the bores are X thou bigger than the one set of new pistons he has in front of him at the same time. I don't really want to debate your topic and you don't seem to have anything to add about engine cylinder bore reconditioning. -- Dave Baker - Puma Race Engines (www.pumaracing.co.uk) |
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"Anthony" wrote in message
... oEmails (Dave Baker) wrote in : I'm not sure why you think you need to measure anything with a machine capable of ten times the resolution of the dimension you are seeking to measure. Because that is precisely what just about any nationally/internationally recognized quality standards require. Your gauge must have an R&R of less than 10% of the tolerance you are measuring, and this must be documented and certified yearly. (Just out of curiosity, when was the last time your gauge was certified?) Heaven help me for adding fuel to this, but the logic behind gage R&R is really going to confuse some people if it isn't explained. And I'm in no mood to explain it -- nor do I trust my memory enough to do it off the top of my head. The point of it, though, is in transferring a dimension *forward* from a certified gage, or *backward* to a certified gage. In other words, if you're using a micrometer that's set to your company's QC-lab gage blocks, and they're qualified from the master blocks you keep in the lab safe, and THEY'RE the ones you send out every six months to Gaithersburg or wherever to have certified, you're going to need that 10% tolerance throughout the chain of instruments and standards. You're also going to need it to get any kind of ISO certification that serious manufacturers require. However, two gages, RELATIVE to each other, don't require it. Depending on the relative accuracy required between, say, an inside and an outside mike, if they're both set to the SAME gage block, for example, the second one only has to be able to resolve less than 50% of the required tolerance. I wrote this down once, years ago, and I hope I have repeated it correctly above. I certainly don't remember the details. But that was something I worked out on paper with one of Mitutoyo's top engineering guys for an article. He was an expert at it, who had a regular path beaten back and forth to Gaithersburg. None of this accounts for such things as measuring errors due to an individual's inconsistencies or thermal expansion, etc. But neither does anything else. The gage R&R business must be in close control and perfectly systematic to have any meaning, too. Ed Huntress |
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Thanks, Ed! More "voice of reason" from you. I can't understand why anyone
would want to argue with the 10:1 convention. It is the instrumentation criterion that is usually quoted in text books and etc. I've heard of it and seen it most all of my life. Anyone choosing to contest such criteria is only revealing his own lack of engineering appreciation and perhaps his training as well. Bob Swinney "Ed Huntress" wrote in message ... "Anthony" wrote in message ... oEmails (Dave Baker) wrote in : I'm not sure why you think you need to measure anything with a machine capable of ten times the resolution of the dimension you are seeking to measure. Because that is precisely what just about any nationally/internationally recognized quality standards require. Your gauge must have an R&R of less than 10% of the tolerance you are measuring, and this must be documented and certified yearly. (Just out of curiosity, when was the last time your gauge was certified?) Heaven help me for adding fuel to this, but the logic behind gage R&R is really going to confuse some people if it isn't explained. And I'm in no mood to explain it -- nor do I trust my memory enough to do it off the top of my head. The point of it, though, is in transferring a dimension *forward* from a certified gage, or *backward* to a certified gage. In other words, if you're using a micrometer that's set to your company's QC-lab gage blocks, and they're qualified from the master blocks you keep in the lab safe, and THEY'RE the ones you send out every six months to Gaithersburg or wherever to have certified, you're going to need that 10% tolerance throughout the chain of instruments and standards. You're also going to need it to get any kind of ISO certification that serious manufacturers require. However, two gages, RELATIVE to each other, don't require it. Depending on the relative accuracy required between, say, an inside and an outside mike, if they're both set to the SAME gage block, for example, the second one only has to be able to resolve less than 50% of the required tolerance. I wrote this down once, years ago, and I hope I have repeated it correctly above. I certainly don't remember the details. But that was something I worked out on paper with one of Mitutoyo's top engineering guys for an article. He was an expert at it, who had a regular path beaten back and forth to Gaithersburg. None of this accounts for such things as measuring errors due to an individual's inconsistencies or thermal expansion, etc. But neither does anything else. The gage R&R business must be in close control and perfectly systematic to have any meaning, too. Ed Huntress |
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"Ed Huntress" wrote in
: None of this accounts for such things as measuring errors due to an individual's inconsistencies or thermal expansion, etc. But neither does anything else. The gage R&R business must be in close control and perfectly systematic to have any meaning, too. Ed Huntress Actually Ed, there is an R&R Study requirement for hand gauges that includes the human element. The basics...are that you aquire a set number of parts (usually 10), and two or more operators. Each part is numbered. Each operator separately gauges each part, and the measurments are recorded by an independent third party, either another person, or by electronic means. Then the range and averages are calculated with respect to the tolerance of the feature, the gauge precision, and other factors to arrive at the repeatability of the gauge, including the human element. Per the quality standards we have to live by, the R&R you spoke of, in combination with this R&R including the human element, must total less than 10% of the tolerance. It is not an easy target to achieve, by any means. -- Anthony You can't 'idiot proof' anything....every time you try, they just make better idiots. Remove sp to reply via email |
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"Anthony" wrote in message
... "Ed Huntress" wrote in : None of this accounts for such things as measuring errors due to an individual's inconsistencies or thermal expansion, etc. But neither does anything else. The gage R&R business must be in close control and perfectly systematic to have any meaning, too. Ed Huntress Actually Ed, there is an R&R Study requirement for hand gauges that includes the human element. The basics...are that you aquire a set number of parts (usually 10), and two or more operators. Each part is numbered. Each operator separately gauges each part, and the measurments are recorded by an independent third party, either another person, or by electronic means. Then the range and averages are calculated with respect to the tolerance of the feature, the gauge precision, and other factors to arrive at the repeatability of the gauge, including the human element. Per the quality standards we have to live by, the R&R you spoke of, in combination with this R&R including the human element, must total less than 10% of the tolerance. It is not an easy target to achieve, by any means. Yeah, there are several components to the whole R&R idea, and anyone who has to deal with today's QC and dimensional measurement, or who might have to know what a customer is talking about, ought to read about it. There are some experts in the business who have written compact little books and so on that describe all of it. I think SME has a good one or two on its book list. Ed Huntress |
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In article , Anthony says...
Actually Ed, there is an R&R Study requirement for hand gauges that includes the human element. The basics...are that you aquire a set number of parts (usually 10), and two or more operators. Each part is numbered. Each operator separately gauges each part, and the measurments are recorded by an independent third party, either another person, or by electronic means. Then the range and averages are calculated with respect to the tolerance of the feature, the gauge precision, and other factors to arrive at the repeatability of the gauge, including the human element. Per the quality standards we have to live by, the R&R you spoke of, in combination with this R&R including the human element, must total less than 10% of the tolerance. It is not an easy target to achieve, by any means. This is a restatement of my experience that "the new guys always gage parts *small* on the OD, and *large* on the bores. This is because consider the reading correct when the micrometer or caliper is cranked on/in there really tight. I used to tell them to run the parts tight/loose as the case would be, to get their lot to come in on target. But picking up a job that had been run unsupervised by a "new guy" during the day would invariably start with double-checking any measurement which required any kind of sensitive feel when gaging. Jim -- ================================================== please reply to: JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com ================================================== |
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"Dave Baker" wrote in message ... I understand there's no particular reason you ought to know what I do or that I'm one of the leading specialists in engine design and theory in the UK "Never trust anyone who asks you to." So please, no bloody stupid room 101 test questions about where the datum point for measuring the o/d on a piston skirt is because if you really want to get into engine theory with me I'll blow you out of the f***ing water. Now you're getting nasty Dave. You're actually not the only person here who cuts metal professionally. I watch Monster Garage from time to time. It's interesting to watch them make custom body panels. They hack away at them and then use Bondo (sp?) to cover up all the marks, dents, scratches, etc. While this makes for a single *interesting* vehicle, I wouldn't want to make a million panels like that... Regards, Robin |
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