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Author Topic: Replacement drive shaft for DP70 Leo Enticknap Film God Posts: 7474 From: Loma Linda, CA Registered: Jul 2000 posted 02-23-2014 07:39 PM                        quote: Steve Matz I think German pride is coming here. There is no way a piece like that should be costing 1700 dollars. I'm not totally sure that this gouging. Most of my time in the biz was spent either in Cinemeccanica or Kinoton booths. The essentialy difference between the two was that Cinemeccanica = spare parts were cheap, things did wear out and break but pretty much every repair you were likely to need to do could be done with a basic toolkit and some common sense. Kinoton = bombproof machines, needed very little maintenance apart from intermittent oil changes and plastic gate components replaced ... but when they did go wrong, the parts were expensive and the repair needed advanced engineering skills and often specialist tools. I remember once paying £300ish (about $450) for an FP20 intermittent shaft - a little milled piece of steel about half the size of a pencil. As Pete points out, this drive shaft is a part that is designed to last the life of the projector (and furthermore a 50-year old projector of which there are probably only around a couple of hundred left in regular use worldwide, if that), not to need regular replacement. So there would never have been many spares sitting around in dealers' stocks in the first place, and the factory would not have been making new ones regularly for at least 30-40 years. Furthermore, it's a precision engineered part that takes a significant amount of highly skilled labor to make. Add to that you've got the forex, shipping and customs overheads that come with importing anything from overseas (in fact, given the USD/EUR exchange rate, that part would probably have cost $2k if you'd bought it a year and a half ago) There may be new materials and production techniques (e.g. 3D printing) that could enable an existing one to be scanned and reproduced without the economy of scale disadvantage that comes with bespoke (rather than mass) production. But if there aren't, and knowing the Kinoton design/manufacture philosophy, $1,700 doesn't sound totally outrageous to me.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 02-23-2014 08:18 PM                     You also have to take into consideration that they've stored these parts in warehouse(s) for in excess of 50 years! That also costs money and that is always factored into the parts cost. It is also highly likely the new shafts thay have were actually made by Phillips in Holland. Steve... I used to own a complete machine shop when I lived in Chicago. I had verticle mills, several size lathes and surface grinders among the normal machine tools in the shop. I couldn't have made that part. No way, no how. The O.D. of that shaft is precision ground as is the worm that drives the oil pump ground into it. The bearing O.D.'s whch are both different are also presision ground. There are holes precision located that are drilled and reamed for the gear and hub split pins. I could have roughed that shaft out on the Hardinge but then it would have had to go to a place that does OD grinding between centers. to do the finish and then to a gear hobbing shop to have the worm roughed in and then ground. You can see in the picture the brass flywheel and the stainless steel (non magnetic) hub in this dailies projector I used to manufacture. Even on a precision Hardinge I could only hold .02 run out. Not good enough for a flywheel! I held that tolerance and then had the entire O.D. ground in one pass by a friend that owned another machine shop. He was able to hold .0009' on runout with Abec 7 bearings in place and that was more than acceptable. The grinding was done on the actual bearings that the flywheel would run on and the entire grinding operation was done in one single pass front to back. I also manufactured hardened steel shutter shafts for Century projectors to match up with LaVezzi's hardened verticle shaft. That entailed a roughing operation which I did, two seperate heat treatment operations which took the shafts to Rockwell 60 hardness, and the final O.D. done on a centerless grindng machine by a company in New York. There is so little tolerance on the O.D. of shafts used in a century because of the type of ball bearings used. Anyway, No existing CNC is gonna give you a ground finish tolerance on heat treated steel like that! I've been to LaVezzi many times seen how they make the parts, same for Wolk. Mark  |  IP: Logged Steve Matz Jedi Master Film Handler Posts: 672 From: Billings, Montana, USA Registered: Sep 2003 posted 02-23-2014 09:02 PM                     Well I've seen these Machines work in person and nothing is going to change my mind of what I just said. They make precision parts that have to turn 10 times the speed that a Projector Shaft has to Turn and last 500 race miles. I think if you saw that Hurco in action you would be a believer, After all this shaft was originally produced by past Machinery that didn't have the accuracy of today's high end CNC's or even Computerized Verical Mills.If a part that's turning 1440rpm still snaps off like that just turning a projector mechanism that doesn't say too much about Rockwell hardness...  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 02-24-2014 10:42 AM                     The shafts in the DP-70 are not hardened shafts! If you had read all the previous posts you'd know that. And there is a huge difference between precision machined and precision ground and precision machining generally precedes precision grinding but apparently my last post didn't get that across. If the CNC was accurate enough then grinders would be disappearing quickly which is simply not the case. If you visit LaVezzi Precision you're going to see a lot more grinders there than CNC machines! And yes I have seen the Hurco machine. Strong used one to machine their main projector castings. Would you like to see pictures of it?  |  IP: Logged Pete Naples Phenomenal Film Handler Posts: 1565 From: Dunfermline, Scotland Registered: Feb 2001 posted 02-24-2014 11:25 AM                     I think the German machinists who made these parts might be somewhat offended to be told they "didn't have the accuracy of today's high end CNC's".! They most certainly did.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 02-24-2014 12:13 PM                     You're right Pete! They actually worked to even tighter tolerances with hand operated machinery than modern CNC machines can deliver. Micron tolerances on the intermittents I know for sure. While machined surfaces and so-so tolerances may be ok for motorcycles they generally don't contribute to long lasting movie projectors. Mark  |  IP: Logged Pete Naples Phenomenal Film Handler Posts: 1565 From: Dunfermline, Scotland Registered: Feb 2001 posted 02-24-2014 12:53 PM                     I've been in the factory, and seen how they work. As someone who grew up around machines and machinists, (think gunsmithing and watchmaking). I was impressed.  |  IP: Logged Steve Matz Jedi Master Film Handler Posts: 672 From: Billings, Montana, USA Registered: Sep 2003 posted 02-24-2014 04:42 PM                     No one was knocking the German's on their ability to produce superior Products in a Variety of Fields.I'm just Telling you you aren't going to find any higher Accuracy than what these Machines have today and at the speed they can maintain that accuracy. I have plenty of Machine Shop Experience going back to the 70's so I'm not just some Layman bragging up someone's Product.I have run every type of Machine that was ever in any type Automotive Engine Shop and maintaining 1/10 thousands accuracy is old Hat. Even DEVRY'S 1940 advertising of their 12000 series intermittents claims that same Tolerance. When you start discussing 1/100 thousands consist accuracy then your in a whole new ball game. If you were familiar with modern CNC's than you would know that they have Grinder attachments for doing work on Billet Tool Steel Material which a Carbide Cutter is incapable of machining... Enough Said on my Part of this Issue. We all have our own Opinions but I will put up my Machine Shop Skills up against anybody who thinks they know everything about being a Machinist....  |  IP: Logged Leo Enticknap Film God Posts: 7474 From: Loma Linda, CA Registered: Jul 2000 posted 02-24-2014 07:10 PM                        Regardless of the machine tool specifics of creating a replacement drive shaft, the fact that the DP70s in existence are all between around 40 to 60 years old, but yet a significant number of them remain in daily, revenue earning service, and parts are still available from the OEM strikes me as a testament to Philips/Kinoton engineering and after-sales support. I mean, if you walked into your local Ford dealership and asked for a replacement gearbox for a 1959 Skyliner, or called up Lockheed wanting a new wing spar for a Constellation (both of these were in production at the same time as the DP70), you'd get a rather surprised response!  |  IP: Logged Sam D. Chavez Film God Posts: 2153 From: Martinez, CA USA Registered: Aug 2003 posted 02-24-2014 07:19 PM                       Steve, You're the only one here making this topic about you instead of the relative accuracy back in the day vs. today. This is more about accuracy at what cost, relative to the past. My cousin ran an a high volume aerospace machine shop in the early '60's, for customers such as Lockheed before CNC was happening. Tolerances requirements were just as demanding then as they are now for similar industries. Nobody is challenging your skills as a machinist, nobody really cares. It's more about getting the job done to whatever accuracy is required either by people power vs. an automated machine. Our little industry never really scales up to needing large quantities. There are only 110,000 cinemas in the entire world after all. Supply and demand is why a shaft ends up costing $1,700 in a cottage industry.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 02-25-2014 06:06 AM                     quote: if you walked into your local Ford dealership and asked for a replacement gearbox for a 1959 Skyliner, or called up Lockheed wanting a new wing spar for a Constellation (both of these were in production at the same time as the DP70), you'd get a rather surprised response! In a prior life, I used to work on a Model-A Ford (1930, in particular). Oddly enough, if you needed a replacement carburetor, Ford still supplied a suitable replacement in the "Motorcraft" brand box by Tillotson (model-X). I just checked and one can STILL get the thing new. While that was not the original carb...I was always amazed at how well supported the Model-A was (and apparently still is). I think the DP70 was well supported because of what it was, where it was located and the fact, it didn't consume much in the way of parts.  |  IP: Logged Leo Enticknap Film God Posts: 7474 From: Loma Linda, CA Registered: Jul 2000 posted 02-26-2014 01:24 AM                        [apologies for going slightly OT] My cousin's first car was a 1967 Morris Minor, which he got in the late '90s. Along with learning to drive on it, he virtually "D-checked" the thing himself, in the process of which he discovered that new replacements of almost every single component part are still being made. Either they are parts that are still used in more recent vehicles (e.g. the spark plugs), or ones made for other vehicles that can be adapted pretty easily to go in a Minor, or like-for-like replacements made by an aftermarket manufacturer that specializes in selling to classic car enthusiasts. From the owners' club magazines and catalogs he showed me (this was just before you'd go online to get this sort of stuff), I formed the impression that you could probably build a whole new Minor out of the bits you could buy from various places. But [trying to return to topic] around one and a half million of these things were made, and so the economies of scale involved mean that there is still probably a market of tens of thousands of customers for parts to keep the remaining ones alive. As Sam points out, the number of DP70s still running is a tiny fraction of that, which makes it all the more impressive that the OEM can still supply a replacement part, that was never intended to be a life-limited one at all, for a model that has been out of production for so long.  |  IP: Logged Sam D. Chavez Film God Posts: 2153 From: Martinez, CA USA Registered: Aug 2003 posted 02-26-2014 10:46 AM                       I made hand built readers for the DP70 as a trade show piece thinking I would sell maybe 25 sets tops or I would have gone the CNC route. To my surprise, I sold over 10 times that amount because people did not want to give them up. Still have a few in stock. Now back to your regularly scheduled program in progress...  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 02-26-2014 01:52 PM                     And those castings were so old the cast iron was incredibly difficult to machine off. Cast iron hardens with age and all I can say is DAYUM! I finally resorted to using a band saw to cut most of it off and even that was time consuming. Then a solid carbide end mill to do the finish work. The carbide end mills would only last for four or five castings. The slot in the sound drums had to be opened wider by plunge grinding. The drums were hardened at the factory to RC65!  |  IP: Logged Pete Naples Phenomenal Film Handler Posts: 1565 From: Dunfermline, Scotland Registered: Feb 2001 posted 02-26-2014 02:05 PM                     There's a pair of your finest in Edinburgh Sam Now semi-retired of course, but still in use when required.  |  IP: Logged

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