Files to print Myford ML4 change gears

I was discussing the idea of printing gears for my Myford ML4 with a buddy of mine who works for Arcam in the US of A. We had started out talking about domestic hobby type printers and he offered to print me some gears if I could supply the relevant files. I have created a Makerbot account on Thingyverse and looked for files and come up with some for the Myford ML7 and Super 7 which I believe are the same as the ML4 apart form having a keyway in the bore and a lack of holes for the silver steel wire to make up the compound sets, no big problem. Is there anywhere else to look for files besides Thingyverse and should I be able to create the necessary type of file in Fusion 360, which I am scratching about with, please?

Also any thoughts on the relative merits (or not) of delta printers over their cartesian cousins? I am told the Delta printers print faster but dont know enough about either type yet!

Hi Nige,

I'm only new to 3D printing myself but got some good advice from this thread : http://www.model-engineer.co.uk/forums/postings.asp?th=131243. You will find it in the View all topics section and under 3d printing . What lathe xxxxx 3d printer should i buy ? I only know of atlas lathe gears on thingiverse as mrpete222 did a video on them recently and was a mazed at how strong they were .

Ian .

I use OnShape (onshape.com) for 3D design which is free if you don't mind your designs being public. there is a 'macro' available which let's you design a gear and plop it in your model (mod, number of gears, thickness ...). Just drop the values in and plop, it's there. Then you put a hole and keyway in. Then you export to stl.

I've printed some gears from this, more to get a feel for the process than for a particular purpose, and they are definitely gears. I've not attempted to use them in a lathe, but see no reason why this wouldn't work fine.

Iain

Fusion 360 has a spur gear generator built in under the "ADD INS" tab. I made a test 20 DP gear and it looks fine compared with the S7 changewheels.

HTH

Rod

I used Grabcad for a couple of gears recently, even if the DP is wrong you can scale them up or down so long as the tooth count and pa. are correct.

Download software from eMachineShop and draw your own gears.

https://www.emachineshop.com/

eMachineShop is a CNC manufacturing company that you can order order parts online that you have designed youself. They supply free CAD software which contains a module (pardon the gear pun) which will draw spur gears which you can export in .dxf format.

I intend to 3D print a 127/100 tooth gear for my Southbend lathe so I can cut metric threads. (When I find a roundtuit).

I imported the dxf file into Solidworks to create a 3D model of a 60 tooth gear and then saved it as an stl file.

Then made a test print to compared with one of the change gears on the lathe. Results were very close.

Now have to build an enclusure for the printer so I can print the gears with nylon filament. This blue test gear below did not take very long to print but the 127/100 gear will take an estimated 15 hours if I make it solid instead of honeycomb fill.

Paul.

Edited By Paul Lousick on 20/02/2018 11:24:55

Delta vs. Cartesian

There's absolutely no practical difference in speed as both types of printer can move the print head vastly faster than you can feed filament through a nozzle.

Deltas have a round bed, can easily be made tall and generally take up less room for a given print area. This means they work well for people making tall, round objects, such as statuettes. It's hard to make full use of the print area for square objects so the practical benefit of a bigger print area in a smaller space may doesn't always work out.

Cartesian printers have a rectangular build area, optimised for boxy things. The tend not to be as tall.

Obviously if you don't intend to do prints to the size limit of your printer, it doesn't matter which you have.

Me, I print right up to the edges and I'm considering building a bigger, cartesian, printer as the ability to print sizeable rectangular enclosures would be useful to me.

Can you point me to where to find that macro please?

Russell

Hi guys,

This is a very handy tool imo

http://www.rushgears.com/tech-tools/part-search/build-custom-gears

I use this utility:

hessmer.org/gears/InvoluteSpurGearBuilder.html

It gives you a downloadable file (just an outline of the teeth and a centre circle for a pair of gears).

With very few numbers it not only does internal, external and rack, it also allows you to create an addendum shift.

I have had success printing gears generated by this program.

Neil

Thank you everybody. I have sent a file to my buddy across the pond and just waiting for some feedback

Have a look at this one Gears 3d Printer

**LINK**

Finally got back to this project and took a short cut by downloading some Myford gears from a contributor to Thingiverse. However, I immediately came unstuck when I imported the file to Ultimaker Cura. The 65 tooth gear opened up in Ultimaker as a tiny object about 6mm across and 0.3mm thick instead of the 3 inches in diameter i was expecting. I realise I can scale the model but that is of limited use unless you know the dimensions the object is supposed to have and shouldn't really be necessary should it?. It seems that somewhere the original dimensions of the object have been lost and I'm scratching my head as to why this should be? Any ideas please ?

STLs don't include any information on scale i.e. what measuring units to use. Try changing your programme settings or multiply size by 25.4.

If you deign in imperial then load it into something expecting metric... if you confused radius and diameter a 6" gear could easily become a 3mm one.

Cura, by default, assumes part dimensions are in metric (mm). AFAIK you can't change this in Cura (possibly in later versions than mine?).

So you're stuck with, either setting up the CAD program used to generate the STL to use metric dimensions (not helpful for STLs downloaded from Thingiverse) or you have to scale up by 25.4 in Cura for STLs originally modelled in inches.