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Post by coniston on Nov 12, 2020 21:05:20 GMT
My EMCO Maximat Super 11 lathe has a gear box for threading and feeds. Like all lathe gearboxes there has to be a limitation to the number of different threads available and although it is an imperial machine there is a good range including some metric as it has a 127 tooth gear in the standard gear train. However one useful thread pitch it doesn't have is 26TPI. To overcome this there is a factory accessory in the form of a range of change gears which allows thread cutting of pretty much every pitch you can think of both metric and imperial. Unfortunately EMCO spares and accessories are like the proverbial rocking horse poo and finding a set of change wheels is nigh on impossible and even if available I suspect a kings ransom would be asked for. I have deduced the gears are metric Module 1 form and gear blanks are available at reasonable prices, particularly from China, however I got thinking that maybe a plastic type would be suitable having seen other latkes supplied with these so my thoughts turned to 3D printing some. First problem is to come up with a 3D model of the gear, after some head scratching and internet searching I stumbled across a parametric design from SCAD which got more brain cells actively jumping around and I started looking further into Fusioin360 only to discover there is a gear design add on which is accessible even on the free version. just pop in the numbers in the table and in an instant a complete 3D model of the required gear design appears. Gear design input dialogue box  And the 3D model  Once modified to add a 4mm key way and converted to .stl it was into the slicer then the printer and within a couple of hours a near perfect gear appeared. I did make the first one with only 10% infill and 0.3mm layer height just to see what it was going to look like, this is the one in these photos. It is not the same size as the original metal one but you can clearly see there is promise in using this method of manufacture.   So I am now printing a 90 Tooth one to use in the existing gear train just to see if it actually takes the loads.  Currently it is printing in PLA but I have some carbon filled PLA which I will try. There are other carbon filled materials such as PETG or ABS which could be a better choice but I'm not going there until I have proven the concept a bit more. And I have Prusa Mk3S on order due to arrive next week so hopefully I'll get some better print quality from that machine. Chris D |
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Post by ettingtonliam on Nov 13, 2020 8:19:53 GMT
I was given a 3D printed 20T 14DP gear to trial on my 100 year old Drummond lathe. I have no idea what material was used (other than the fact that its blue!), but its been in use as the mandrel gear on the fine feed train for the past few months and seems to be fine. I have made a number of 'proper' cast iron changewheels for myself and others in the past, but for speed and cost I can't come near the 3D printed ones.
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Post by Roger on Nov 13, 2020 19:04:44 GMT
This is a great use of 3D printing, the loads are pretty small so I imagine they will last very well. I've made them from Aluminium and Delrin in the past, and those materials are perfectly acceptable too. I presume they were originally made from CI because at the time it was the cheapest and simplest option rather than they need to be that material.
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Post by coniston on Nov 13, 2020 19:21:42 GMT
This is a great use of 3D printing, the loads are pretty small so I imagine they will last very well. I've made them from Aluminium and Delrin in the past, and those materials are perfectly acceptable too. I presume they were originally made from CI because at the time it was the cheapest and simplest option rather than they need to be that material. I'm sure you're right, I think the original ones on the EMCO maybe cast steel judging by the finish on the machined side, trust the Austrians to go 'over the top' . I've seen original machines with plastic, cast iron, steel and cast Al so I guess it all depended on what was cheapest / easiest for the lathe manufacturer. |
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Post by coniston on Nov 13, 2020 19:28:48 GMT
My second version is a direct replacement for the 90 tooth final gear so that I could actually try it on the existing gear train. This one is printed at 0.12 layer height, 5 top, bottom and outer shells and 50% infill, so pretty robust for a print without being completely solid. I had to take the bore out to 19mm, a simple 2 minute job in the lathe and file out the keyway a bit again only a couple of minutes. It fitted really well even without any dressing of the tooth profile and it worked a treat, video here: www.youtube.com/watch?v=YcNn8FL_vxA  I'll wait until the Prusa arrives and sort out some carbon filled material before I print the complete set of 10 gears then I only need to make a bearing stud to complete the set up  Chris D |
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Post by Roger on Nov 13, 2020 20:23:36 GMT
The changewheel looks great, and it will be quieter than metal ones too. My guess is that you could easily get away with less infill, it's the perimeters that really give it the strength.
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Post by ettingtonliam on Nov 14, 2020 11:38:55 GMT
Up to the end of the 19th century, gears were quite often used 'as cast' without any machining of the teeth, other than a light fettling, then run together with generous clearances. I suppose, if you think of the pattern as the 'programme' cast iron was the Victorian equivalent of 3D printing- make a master, then use that to make dozens/hundreds of copies, quickly and cheaply.
I'm highly unlikely to get into 3D printing myself, but even I can see the advantages of it.
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Post by simplyloco on Nov 14, 2020 12:03:55 GMT
Up to the end of the 19th century, gears were quite often used 'as cast' without any machining of the teeth, other than a light fettling, then run together with generous clearances. I suppose, if you think of the pattern as the 'programme' cast iron was the Victorian equivalent of 3D printing- make a master, then use that to make dozens/hundreds of copies, quickly and cheaply. I'm highly unlikely to get into 3D printing myself, but even I can see the advantages of it. I'm glad I bought my Prusa, but it's more for novelty value for me than serious stuff like gears and aircraft fuselages. It's just a very clever hot melt glue gun really! John |
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kipford
Statesman
Building a Don Young 5" Gauge Aspinall Class 27
Posts: 566 
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Post by kipford on Nov 14, 2020 13:37:37 GMT
Chris
Great result.
Dave
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Post by simplyloco on Nov 14, 2020 14:02:20 GMT
My EMCO Maximat Super 11 lathe has a gear box for threading and feeds. Like all lathe gearboxes there has to be a limitation to the number of different threads available and although it is an imperial machine there is a good range including some metric as it has a 127 tooth gear in the standard gear train. However one useful thread pitch it doesn't have is 26TPI. To overcome this there is a factory accessory in the form of a range of change gears which allows thread cutting of pretty much every pitch you can think of both metric and imperial. Unfortunately EMCO spares and accessories are like the proverbial rocking horse poo and finding a set of change wheels is nigh on impossible and even if available I suspect a kings ransom would be asked for. I have deduced the gears are metric Module 1 form and gear blanks are available at reasonable prices, particularly from China, however I got thinking that maybe a plastic type would be suitable having seen other latkes supplied with these so my thoughts turned to 3D printing some. First problem is to come up with a 3D model of the gear, after some head scratching and internet searching I stumbled across a parametric design from SCAD which got more brain cells actively jumping around and I started looking further into Fusioin360 only to discover there is a gear design add on which is accessible even on the free version. just pop in the numbers in the table and in an instant a complete 3D model of the required gear design appears. SNIP Chris D Oh look, someone you know who lives quite near has got the alternate gear set...  The 90T one is on my machine and it's a compound gear!  |
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Post by coniston on Nov 14, 2020 20:47:22 GMT
My EMCO Maximat Super 11 lathe has a gear box for threading and feeds. Like all lathe gearboxes there has to be a limitation to the number of different threads available and although it is an imperial machine there is a good range including some metric as it has a 127 tooth gear in the standard gear train. However one useful thread pitch it doesn't have is 26TPI. To overcome this there is a factory accessory in the form of a range of change gears which allows thread cutting of pretty much every pitch you can think of both metric and imperial. Unfortunately EMCO spares and accessories are like the proverbial rocking horse poo and finding a set of change wheels is nigh on impossible and even if available I suspect a kings ransom would be asked for. I have deduced the gears are metric Module 1 form and gear blanks are available at reasonable prices, particularly from China, however I got thinking that maybe a plastic type would be suitable having seen other latkes supplied with these so my thoughts turned to 3D printing some. First problem is to come up with a 3D model of the gear, after some head scratching and internet searching I stumbled across a parametric design from SCAD which got more brain cells actively jumping around and I started looking further into Fusioin360 only to discover there is a gear design add on which is accessible even on the free version. just pop in the numbers in the table and in an instant a complete 3D model of the required gear design appears. SNIP Chris D Oh look, someone you know who lives quite near has got the alternate gear set... The 90T one is on my machine and it's a compound gear! Yes but they are a different set between V10P and Super 11 mine don't have pins but have keyways and are different no teeth. |
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Post by simplyloco on Nov 14, 2020 21:00:54 GMT
Oh look, someone you know who lives quite near has got the alternate gear set... The 90T one is on my machine and it's a compound gear! Yes but they are a different set between V10P and Super 11 mine don't have pins but have keyways and are different no teeth. Now there's POSH! No teeth!  |
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Post by coniston on Jan 17, 2021 21:32:34 GMT
Finally to conclude this exercise, I have now made the other components to mount the additional change gears namely a stud, bearing with key, square nut for stud, knurled nut for bearing and a 4mm spacer. I had been putting this off as the bearing which carries two gears keyed together requires an m18 x 2mm thread and a matching knurled nut. But the light came on in my dim mind this week and I created a 3D printed one of each. I included the 4mm key into the bearing as well just to se if it would work. I printed the bearing in PETG which I think will be a better bearing material than PLA. I do have some Nylon filament but haven't yet tried using that and from what I've read it is a difficult material to get successful prints from, something to try another day maybe? This is the gear train I need to create for a 26 TPI thread  Here are all the gears I have made, this constitutes the complete set as shown in the manual. along with the other parts for the banjo stud. The bearing is the black printed part.  And a close up of the stud parts, the grey bearing was a first trial printed in PLA without supports vertically as shown, surprising how well it managed the overhangs without supports and how well the thread came out. I had to increase the clearance of the two threaded parts to get them to screw together nicely without binding, but it only took a couple of trials to get it right.  Here's the original EMCO bearing against the 3D printed ones for comparison. PETG doesn't print as cleanly as PLA but is a much more resilient material.  This shows the arrangement for 26 TPI thread, the new stud is the lower left one. It runs lovely and smooth with no perceptible noise.  And here is the trial piece I did, 3/4" x 26 BSB thread on a piece of 3/4" brass bar. Another quirk of the Emco is the thread dial indicator has three gear ratios, 14, 15 and 16 used depending on which threads are being cut, I didn't realise this to begin with and wondered why my first attempt went haywire until I changed from the 15 tooth to 16 tooth gear set up. This is easily changed by sliding the thread dial indicator up or down on it's mount, just something else to catch out the unwary.  After this I dismantled the gear train to return it to normal operation and there was absolutely no sign of any distress of the new components so I will take this as a success. Chris D |
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Post by Bluff Chuffer on Jan 18, 2021 4:49:10 GMT
Any chance of putting the files on Thingiverse?
I have two Emco 11's and the complete change gear set, but one never knows.
There is a set for a Drummond available on Thingiverse, plus feed screw nuts for a Southbend or Boxford's.
Good work!
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Post by coniston on Jan 18, 2021 10:10:03 GMT
Any chance of putting the files on Thingiverse? I have two Emco 11's and the complete change gear set, but one never knows. There is a set for a Drummond available on Thingiverse, plus feed screw nuts for a Southbend or Boxford's. Good work! Haven't thought of that, maybe I'll have a look into it. You're a lucky guy having 2 Emco 11's. they are like rare as hens teeth over here. I have to say in general I love the lathe but the speed range frustrates me a bit so will look into changing to VFD in the future. The other thing I don't have are the steadies, so far not needed to use either but may have to make them at some time. Chris D |
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jc54
Active Member
Posts: 12
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Post by jc54 on Mar 1, 2021 19:44:25 GMT
For any Myford owners out there. I found a 127tooth gear on thingiverse. Printed in PLA for a friend he was that pleased with it I printed one for my ML7. Not used by me in anger yet but friend is very pleased with this difficult to find gear. John
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