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Gears again - identifying
I'm trying to replace some crashed spur gears in the QC box on an Enco
1024. Enco is no help. I downloaded a Martin Gear Catalog and am trying to figure out what to order. I'm measuring a Pitch Diameter = .773 How do I determine what the pressure angle is? The valley between each tooth is radiused. Martin calls that a Shaper-cut profile. Is that significant? The guy a Purvis Bearing talked like this is rocket science. Is there a better way to do this? -- - - Rex Burkheimer WM Automotive Fort Worth TX |
Rex B wrote:
How do I determine what the pressure angle is? One way is: If you have a gear with the same TPI and a _know_ pressure angle mesh them together and messure the distance. If it has the expected*) one, the unknown wheel has the same pressure angle, if not then not. Also, if you look at the kind of gear (Norton?) chances are damned high that it has the standard pressure angle (don't know it for imperial based gears without looking it up in a book) *) Have to look in a book for the imperial based system, if you want. But it will take about 10 hours. It's time to go to bed right here. :-) Nick -- Motormodelle / Engine Models: http://www.motor-manufaktur.de Ellwe 2FB * VTM 87 * DLM-S3a * cubic more to come ... |
Rex B wrote:
I'm trying to replace some crashed spur gears in the QC box on an Enco 1024. ... Me too, kinda (mine is a Jet 1024). I took the gear into a local bearing store (Eastern Bearing). The guy searched for the longest time and concluded that it wasn't anything standard and he couldn't help me. This place is a Boston Gear distributor, so I figured that it wasn't worth looking anywhere else. Leigh (CATRUCKMAN) says that he carries Jet parts and I emailed him, but haven't had a response. I also emailed another Jet parts dealer that I found online. Haven't heard from him either. I'm leaning toward hobbing my own. Bob |
Rex B wrote: I'm trying to replace some crashed spur gears in the QC box on an Enco 1024. ... I finally gave up and bought a set of gear tooth gages from McMaster. It was a dollarectomy but now I absolutely know what gear something is. Well, as long as it's 14.5° or 20° pressure angle, that is... those are the "standard two" nowadays. I know there exist metric gear standards but I don't know at all how to measure those. Hmmm ... another way would be if you could borrow some time on an optical comparator, and if you could actually trace the profile of one of the teeth at 20X, and get a bunch of measurements, I bet you could match it up that way. GWE |
I believe that the pressure angle could be determined by measuring the
diameter over pins of two different diameters. I know this can determine the angle of a V slot. I do not know the mathematics needed for gear teeth angles. I have a gear tooth caliper but have not tried to learn how to use it to determine the pressure angle. Don Young "Grant Erwin" wrote in message ... Rex B wrote: I'm trying to replace some crashed spur gears in the QC box on an Enco 1024. ... I finally gave up and bought a set of gear tooth gages from McMaster. It was a dollarectomy but now I absolutely know what gear something is. Well, as long as it's 14.5° or 20° pressure angle, that is... those are the "standard two" nowadays. I know there exist metric gear standards but I don't know at all how to measure those. Hmmm ... another way would be if you could borrow some time on an optical comparator, and if you could actually trace the profile of one of the teeth at 20X, and get a bunch of measurements, I bet you could match it up that way. GWE |
Don Young wrote:
I believe that the pressure angle could be determined by measuring the diameter over pins of two different diameters. I know this can determine the angle of a V slot. I do not know the mathematics needed for gear teeth angles. I have a gear tooth caliper but have not tried to learn how to use it to determine the pressure angle. Don Young Roll a gear across some placticine on a flat surface. You can pretty much see the pressure angle with the help of a protractor. Look at the included angle of the two faces. If you rolled the gear reasonably smoothly, you should have a rack impression with straight faces on the teeth. At least, if the gear is reasonably close to correct tooth form to begin with. Notice that the tooth form for 14 1/2 deg rack is pretty much an Acme thread form tool (29 deg angle) Easy reference point to determine if it matches or is wider, which would make it 20 deg angle (40 deg included) |
Rex B wrote:
I'm trying to replace some crashed spur gears in the QC box on an Enco 1024. Enco is no help. I downloaded a Martin Gear Catalog and am trying to figure out what to order. I'm measuring a Pitch Diameter = .773 How do I determine what the pressure angle is? http://www.bostongear.com/pdf/upload..._pg133-153.pdf Print out page 136 then hold the gear up to each of the pictures. Nate |
trevor jones wrote:
Roll a gear across some placticine on a flat surface. That is clever! will try to remember that. Nick -- Motormodelle / Engine Models: http://www.motor-manufaktur.de Ellwe 2FB * VTM 87 * DLM-S3a * cubic more to come ... |
Bob Engelhardt wrote: Rex B wrote: I'm trying to replace some crashed spur gears in the QC box on an Enco 1024. ... Me too, kinda (mine is a Jet 1024). I took the gear into a local bearing store (Eastern Bearing). The guy searched for the longest time and concluded that it wasn't anything standard and he couldn't help me. This place is a Boston Gear distributor, so I figured that it wasn't worth looking anywhere else. Leigh (CATRUCKMAN) says that he carries Jet parts and I emailed him, but haven't had a response. I also emailed another Jet parts dealer that I found online. Haven't heard from him either. I'm leaning toward hobbing my own. I'm getting there myself. Never made a gear before, and frankly I don't have that much shop-time to fool with it. I'd rather buy something even if I have to cut the old one off the hub and size the new one to press on. At least I have a perfect pattern, as the gear next to it is identical. Rex |
Grant Erwin wrote:
Rex B wrote: I'm trying to replace some crashed spur gears in the QC box on an Enco 1024. ... I finally gave up and bought a set of gear tooth gages from McMaster. It was a dollarectomy but now I absolutely know what gear something is. Well, as long as it's 14.5° or 20° pressure angle, that is... those are the "standard two" nowadays. I know there exist metric gear standards but I don't know at all how to measure those. The guy at the Bearing place pulled out his gear tooth gauges (didn't know those existed) and nothing matched. Rex |
Last time I ran into this I set the gear on my scanner, took a very
large blowup of a few teeth, then compared the shape to the drawings in machinery's handbook. Mine was very obviously a 14-1/2 degreee pressure angle. You can get a very accurate diametrical pitch by mating any two gears, measuring the centerline distance, and counting the teeth in BOTH gears. DP = total tooth count/distance. These tricks work for inch gears, metric uses a different appoach. And anything from ENCO should be considered to have metric gears. If you calculate a DP that is not some nice even multiple (eg 6,10,20, 24 ,etc etc.), more than likely you have a metric gear. If the valley is radiused, it has no effect on gear teeth meshing, it does reduce the ultimate load carrying capacity. As for the rocket science, I've been experimenting with cutting sample and prototype gears on a CNC mill. Messy yes, Rocket science, no. Rex B wrote: I'm trying to replace some crashed spur gears in the QC box on an Enco 1024. Enco is no help. I downloaded a Martin Gear Catalog and am trying to figure out what to order. I'm measuring a Pitch Diameter = .773 How do I determine what the pressure angle is? The valley between each tooth is radiused. Martin calls that a Shaper-cut profile. Is that significant? The guy a Purvis Bearing talked like this is rocket science. Is there a better way to do this? |
As the Enco 1024 is an import it is almost certain that you have
module [metric] gears and not P.D. [inch] gears. See Law's book on gear cutting for indepth discussion of P.D. v module. see http://www.powells.com/biblio/66-0852429118-1 I have this book and find it to be a valuable reference in addition to telling you how to cut both involute and cycloid gearing. Powell's is good to deal with. ====================================== On Mon, 15 Aug 2005 17:06:23 -0500, Rex B wrote: I'm trying to replace some crashed spur gears in the QC box on an Enco 1024. Enco is no help. I downloaded a Martin Gear Catalog and am trying to figure out what to order. I'm measuring a Pitch Diameter = .773 How do I determine what the pressure angle is? The valley between each tooth is radiused. Martin calls that a Shaper-cut profile. Is that significant? The guy a Purvis Bearing talked like this is rocket science. Is there a better way to do this? |
F. George McDuffee wrote:
As the Enco 1024 is an import it is almost certain that you have module [metric] gears and not P.D. [inch] gears. See Law's book on gear cutting for indepth discussion of P.D. v module. see http://www.powells.com/biblio/66-0852429118-1 I have this book and find it to be a valuable reference in addition to telling you how to cut both involute and cycloid gearing. Powell's is good to deal with. OK, I've been eyeing this book for a while, so I ordered it. With all respect to Powell, Amazon had it for half via some guy in Oklahoma. I'll probably wind up grinding a single-point form tool and making a couple of these on my minimill. I will also have to make a mandrel and find a reamer or two. I'll probably need a better grinder, or at least a new wheel. And I'll get to try out that indexer I lucked onto a while back. It's ratio is 1:48, so I won't even need to use the plate to cut this 16-tooth gear. Just cut a tooth, crank 3 times, cut, repeat 14 more times, right? Looks like I need to source some 1.375 round stock in leaded steel. What alloy do I need to specify? This is a quick-change gear, so doesn't need to be high-strength. I suspect a brass gear would do the job. I'd enjoy this project more if I had the liesure time to give up a day for it. I just hate having a nice tool partially assembled, so I'd better get on it. Much thanks for all the help, guys. I'll let you know how it goes. Rex Burkheimer Ft Worth |
Just ran across this site.
http://www.aardvark.co.nz/pjet/gears.shtml Pretty much exactly what I planned to do. I had not thought of using the boring head, but since I have a brand new 3" R8 head ($10) I can use that. - - Rex B Rex B wrote: F. George McDuffee wrote: As the Enco 1024 is an import it is almost certain that you have module [metric] gears and not P.D. [inch] gears. See Law's book on gear cutting for indepth discussion of P.D. v module. see http://www.powells.com/biblio/66-0852429118-1 I have this book and find it to be a valuable reference in addition to telling you how to cut both involute and cycloid gearing. Powell's is good to deal with. OK, I've been eyeing this book for a while, so I ordered it. With all respect to Powell, Amazon had it for half via some guy in Oklahoma. I'll probably wind up grinding a single-point form tool and making a couple of these on my minimill. I will also have to make a mandrel and find a reamer or two. I'll probably need a better grinder, or at least a new wheel. And I'll get to try out that indexer I lucked onto a while back. It's ratio is 1:48, so I won't even need to use the plate to cut this 16-tooth gear. Just cut a tooth, crank 3 times, cut, repeat 14 more times, right? Looks like I need to source some 1.375 round stock in leaded steel. What alloy do I need to specify? This is a quick-change gear, so doesn't need to be high-strength. I suspect a brass gear would do the job. I'd enjoy this project more if I had the liesure time to give up a day for it. I just hate having a nice tool partially assembled, so I'd better get on it. Much thanks for all the help, guys. I'll let you know how it goes. Rex Burkheimer Ft Worth |
snip
Looks like I need to source some 1.375 round stock in leaded steel. What alloy do I need to specify? This is a quick-change gear, so doesn't need to be high-strength. I suspect a brass gear would do the job. It will be a major project to machine a steel gear. Because of the low speeds/loading on the change gears we have found that aluminium work fine [we sued some 6061 T6 we happened to have] also the mechanical grade of micarta or formica makes good gears. This was a common timing gear material. Drimel tool or 1/8 air grinder will be very helpful in hand grinding the involute profile into a single point cutter. Unless you like grinding use the smallest piece of tool steel you can. 3/16 is plenty for 1.0 module. You will need to grind the top of the tool down to center of the holder or grind in hook to avoid negative rake. |
Rex B wrote:
I'm measuring a Pitch Diameter = .773 How about posting all dimensions you have? #of teeth, outer diameter, base diam., width (might give a hint to "metric"). So I (or others) can look up and see if I/they find out what it is? Nick -- Motormodelle / Engine Models: http://www.motor-manufaktur.de Ellwe 2FB * VTM 87 * DLM-S3a * cubic more to come ... |
F. George McDuffee wrote:
snip Looks like I need to source some 1.375 round stock in leaded steel. What alloy do I need to specify? This is a quick-change gear, so doesn't need to be high-strength. I suspect a brass gear would do the job. It will be a major project to machine a steel gear. Because of the low speeds/loading on the change gears we have found that aluminium work fine [we sued some 6061 T6 we happened to have] also the mechanical grade of micarta or formica makes good gears. This was a common timing gear material. That's good to know. I have some 6061 It would make it much easier, plus this gear would make a better "fuse" if it were AL. Drimel tool or 1/8 air grinder will be very helpful in hand grinding the involute profile into a single point cutter. Unless you like grinding use the smallest piece of tool steel you can. 3/16 is plenty for 1.0 module. You will need to grind the top of the tool down to center of the holder or grind in hook to avoid negative rake. I have some 3/16 cobalt steel stock which I'll probably use. Thanks for the input |
Nick Müller wrote: How about posting all dimensions you have? #of teeth, outer diameter, base diam., width (might give a hint to "metric"). So I (or others) can look up and see if I/they find out what it is? Su 16 teeth OD 7.890" Base Dia. 7.577" face width is .377" or 9.56mm I've been trying to scan it, but I can't get enough contrast. |
Rex B wrote:
16 teeth OD 7.890" Base Dia. 7.577" face width is .377" or 9.56mm Eh, sorry, are you pulling my leg? 16 teeth and about 200mm OD with less than 4 mm height of teeth? Or am I dumb and wrong with thinking that 7.89" are 200.406mm? This gear would look _completely_ different from regular ones. puzzled, confused and all Nick -- Motormodelle / Engine Models: http://www.motor-manufaktur.de Ellwe 2FB * VTM 87 * DLM-S3a * cubic more to come ... |
Rex B wrote:
Grant Erwin wrote: Rex B wrote: I'm trying to replace some crashed spur gears in the QC box on an Enco 1024. ... I finally gave up and bought a set of gear tooth gages from McMaster. It was a dollarectomy but now I absolutely know what gear something is. Well, as long as it's 14.5° or 20° pressure angle, that is... those are the "standard two" nowadays. I know there exist metric gear standards but I don't know at all how to measure those. The guy at the Bearing place pulled out his gear tooth gauges (didn't know those existed) and nothing matched. Metric. Yuk. GWE |
Nick Müller wrote:
Rex B wrote: 16 teeth OD 7.890" Base Dia. 7.577" face width is .377" or 9.56mm Eh, sorry, are you pulling my leg? 16 teeth and about 200mm OD with less than 4 mm height of teeth? Or am I dumb and wrong with thinking that 7.89" are 200.406mm? This gear would look _completely_ different from regular ones. LOL I'm doing too many things at once (supposedly to be working for my employer) That should be .789" OK, .7577" base diameter, so tooth height is .031" So this gear is about the size of a half dollar, and about 3/8" thick My apologies. Rex |
Rex B wrote:
That should be .789" OK, .7577" base diameter, so tooth height is .031" OK, this doesn't qualify for a module gear. Module 1 or module 1.25 are common and standardized and they both don't fit (OD wise). With 20° (the standard), that is. Tooth height would be way off (should be about 2mm or 2.5mm for Mod 1 / Mod 1.25). There also exists a Module 1.125 (have never seen that) that would badly match the OD (20.25mm compared to your 20.04mm). If the manufacturer quit the 20°, there is no standard to select from (AFAIK). But there is a last chance. It is legal to play some tricks with tooth-height. If you take the time and mesh two of those gears together (may have different #of teeth, but i need to know. And no tricks this time! :-)) and messure the distance of the centers, I'll give it another try. Nick, gonna have a beer in the meantime ... -- Motormodelle / Engine Models: http://www.motor-manufaktur.de Ellwe 2FB * VTM 87 * DLM-S3a * cubic more to come ... |
Rule to find metric module [there is an inch module but seldom
used now] is to measure the OD of the gear in mm and divide by the number of teeth + 2. 16t +2 = 18 ..789 * 25.4 = 20.046 mm round to 20 20/18 = 1.11 module [doubtful] assuming 1.00 module 16T +2 = 18 X 1.00 = 18mm OD 18 MM/25.4 = 0.7087 inches Any chance of a decimal slip? BTW -- almost all metric gears are 20 degree pressure angle. see http://www.littlemachineshop.com/pro...ProductID=1523 for 1 m/m gear sets for mini lathes or see http://mdmetric.com/kgear.htm http://www.qtcgears.com/RFQ/SpurGears.htm http://www.google.com/url?sa=t&ct=re...MpeQsQHi-fG9Dg http://www.sdp-si.com/herb/spk/sdp-si/D780/D780cat.htm and a bunch more That should be .789" OK, .7577" base diameter, so tooth height is .031" So this gear is about the size of a half dollar, and about 3/8" thick My apologies. Rex |
Nick Müller wrote: Rex B wrote: That should be .789" OK, .7577" base diameter, so tooth height is .031" OK, this doesn't qualify for a module gear. Module 1 or module 1.25 are common and standardized and they both don't fit (OD wise). With 20° (the standard), that is. Tooth height would be way off (should be about 2mm or 2.5mm for Mod 1 / Mod 1.25). There also exists a Module 1.125 (have never seen that) that would badly match the OD (20.25mm compared to your 20.04mm). If the manufacturer quit the 20°, there is no standard to select from (AFAIK). But there is a last chance. It is legal to play some tricks with tooth-height. If you take the time and mesh two of those gears together (may have different #of teeth, but i need to know. And no tricks this time! :-)) and messure the distance of the centers, I'll give it another try. Ok, I'll look at it tonight. Part of the challenge will be figuring out which gear meshes with it. Nick, gonna have a beer in the meantime ... Have two. I know I will ... |
F. George McDuffee wrote: Rule to find metric module [there is an inch module but seldom used now] is to measure the OD of the gear in mm and divide by the number of teeth + 2. 16t +2 = 18 .789 * 25.4 = 20.046 mm round to 20 20/18 = 1.11 module [doubtful] assuming 1.00 module 16T +2 = 18 X 1.00 = 18mm OD 18 MM/25.4 = 0.7087 inches Any chance of a decimal slip? I doubt it. I read 20.05mm off a Mitutoyo digital caliper. This was off an identical undamaged gear. The damaged gear has all the teeth laid over a little, so I did not trust any measurements there. BTW -- almost all metric gears are 20 degree pressure angle. see http://www.littlemachineshop.com/pro...ProductID=1523 for 1 m/m gear sets for mini lathes or see http://mdmetric.com/kgear.htm http://www.qtcgears.com/RFQ/SpurGears.htm http://www.google.com/url?sa=t&ct=re...MpeQsQHi-fG9Dg http://www.sdp-si.com/herb/spk/sdp-si/D780/D780cat.htm and a bunch more I'll study on those later - thanks Rex |
Rex B wrote:
Have two. I know I will ... Oh no! :-) OK, it's midnight here in ol' Germany. I'll have a sleep and you have to wait 9 hours to see me posting again ... Nick -- Motormodelle / Engine Models: http://www.motor-manufaktur.de Ellwe 2FB * VTM 87 * DLM-S3a * cubic more to come ... |
Nate Weber wrote:
http://www.bostongear.com/pdf/upload..._pg133-153.pdf That's a great link, thanks. Print out page 136 then hold the gear up to each of the pictures. I think you meant p 137. Doesn't match mine. I scanned mine at high res and it appears as though the teeth are not even involute. I.e., they are straight sided. Why did they have to do it that way? Bob |
It is entirely possible that the gear is not a standard pitch or module. I
have checked a bunch of engine timing gears and transmission gears and have not found any to be standard sizes. Don Young "Rex B" wrote in message ... F. George McDuffee wrote: Rule to find metric module [there is an inch module but seldom used now] is to measure the OD of the gear in mm and divide by the number of teeth + 2. 16t +2 = 18 .789 * 25.4 = 20.046 mm round to 20 20/18 = 1.11 module [doubtful] assuming 1.00 module 16T +2 = 18 X 1.00 = 18mm OD 18 MM/25.4 = 0.7087 inches Any chance of a decimal slip? I doubt it. I read 20.05mm off a Mitutoyo digital caliper. This was off an identical undamaged gear. The damaged gear has all the teeth laid over a little, so I did not trust any measurements there. BTW -- almost all metric gears are 20 degree pressure angle. see http://www.littlemachineshop.com/pro...ProductID=1523 for 1 m/m gear sets for mini lathes or see http://mdmetric.com/kgear.htm http://www.qtcgears.com/RFQ/SpurGears.htm http://www.google.com/url?sa=t&ct=re...MpeQsQHi-fG9Dg http://www.sdp-si.com/herb/spk/sdp-si/D780/D780cat.htm and a bunch more I'll study on those later - thanks Rex |
|
20.05mm od/(16 + 2) teeth = 1.1139
Another poster suggested there was such a thing as a 1.125 module gear. If so this looks like a good candidate. Next question: why would anyone spec a 1-1/8 mm module gear? GmcD On Tue, 16 Aug 2005 16:51:05 -0500, Rex B wrote: F. George McDuffee wrote: Rule to find metric module [there is an inch module but seldom used now] is to measure the OD of the gear in mm and divide by the number of teeth + 2. 16t +2 = 18 .789 * 25.4 = 20.046 mm round to 20 20/18 = 1.11 module [doubtful] assuming 1.00 module 16T +2 = 18 X 1.00 = 18mm OD 18 MM/25.4 = 0.7087 inches Any chance of a decimal slip? I doubt it. I read 20.05mm off a Mitutoyo digital caliper. This was off an identical undamaged gear. The damaged gear has all the teeth laid over a little, so I did not trust any measurements there. BTW -- almost all metric gears are 20 degree pressure angle. see http://www.littlemachineshop.com/pro...ProductID=1523 for 1 m/m gear sets for mini lathes or see http://mdmetric.com/kgear.htm http://www.qtcgears.com/RFQ/SpurGears.htm http://www.google.com/url?sa=t&ct=re...MpeQsQHi-fG9Dg http://www.sdp-si.com/herb/spk/sdp-si/D780/D780cat.htm and a bunch more I'll study on those later - thanks Rex |
Bob Engelhardt wrote:
Nate Weber wrote: http://www.bostongear.com/pdf/upload..._pg133-153.pdf That's a great link, thanks. Print out page 136 then hold the gear up to each of the pictures. I think you meant p 137. Doesn't match mine. I scanned mine at high res and it appears as though the teeth are not even involute. I.e., they are straight sided. Why did they have to do it that way? Bob This 16-tooth unit definitely has a break about halfway up the tooth |
F. George McDuffee wrote: 20.05mm od/(16 + 2) teeth = 1.1139 Another poster suggested there was such a thing as a 1.125 module gear. If so this looks like a good candidate. Next question: why would anyone spec a 1-1/8 mm module gear? GmcD Well, it's a Chinese lathe, so we are dealing with Oriental logic, such as it is. Probably inscrutable to us non-Asians On Tue, 16 Aug 2005 16:51:05 -0500, Rex B wrote: F. George McDuffee wrote: Rule to find metric module [there is an inch module but seldom used now] is to measure the OD of the gear in mm and divide by the number of teeth + 2. 16t +2 = 18 .789 * 25.4 = 20.046 mm round to 20 20/18 = 1.11 module [doubtful] assuming 1.00 module 16T +2 = 18 X 1.00 = 18mm OD 18 MM/25.4 = 0.7087 inches Any chance of a decimal slip? I doubt it. I read 20.05mm off a Mitutoyo digital caliper. This was off an identical undamaged gear. The damaged gear has all the teeth laid over a little, so I did not trust any measurements there. BTW -- almost all metric gears are 20 degree pressure angle. see http://www.littlemachineshop.com/pro...ProductID=1523 for 1 m/m gear sets for mini lathes or see http://mdmetric.com/kgear.htm http://www.qtcgears.com/RFQ/SpurGears.htm http://www.google.com/url?sa=t&ct=re...MpeQsQHi-fG9Dg http://www.sdp-si.com/herb/spk/sdp-si/D780/D780cat.htm and a bunch more I'll study on those later - thanks Rex |
xray wrote:
On Wed, 17 Aug 2005 13:02:02 -0500, F. George McDuffee spake Next question: why would anyone spec a 1-1/8 mm module gear? I think this gear was from the QC box. Its task is to produce exact output ratios by meshing between many gears on fixed shafts. I can't fathom how much fun it must be to design something like that, but I'd think using non-standard gears might be the easiest way to get it done. This 16T gear is on the input (left) side of the box, on the shaft with the main gear-stack. The gears on the left are 16/32-16/32-16, turning independently on bronze bushings, then a cast boss extending from the case, then the multi-gear progressive stack which are keyed to the shaft. It meshes with a 32-tooth gear on one side and the change-lever gear on the other side. The power flow goes: Input stub shaft gear Center shaft, left side (the gear in question is here) left change lever gear Change lever shaft Right change lever gear stepped gears gear on leadscrew or gear on power apron drive shaft. |
F. George McDuffee wrote:
Another poster suggested there was such a thing as a 1.125 module gear. It was me. And no, I didn't suggest it. Because it wouldn't fit and it is damned uncommon. If so this looks like a good candidate. Next question: why would anyone spec a 1-1/8 mm module gear? It has to do with logic. ;-) In the standard, there are arithmetic rows. These are grouped. The most preferred group is the one most common. I.e. Mod. 1, Mod. 1.5. The next group contains Mod. 1,25. The 3rd group (and you need to have a lot of reason to select from this) contains Mod. 1.125. Chances are damned low, that anybody would use a module from the 3rd group. Chances that you get a stock gear from that group in _any_ shop are even lower. Nick -- Motormodelle / Engine Models: http://www.motor-manufaktur.de Ellwe 2FB * VTM 87 * DLM-S3a * cubic more to come ... |
xray wrote:
I can't fathom how much fun it must be to design something like that, but I'd think using non-standard gears might be the easiest way to get it done. Yes. In most cases, you will find one one or two pairs that are standard. The others are non-standard. But, and I asked that Rex, if you do have a norton gear-box, all gears are very likely to be standard. Nick -- Motormodelle / Engine Models: http://www.motor-manufaktur.de Ellwe 2FB * VTM 87 * DLM-S3a * cubic more to come ... |
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