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About printing gears- thank you for your test about printing gear for me it was very instructive, especially the part where the teeth of the wheel were collapsing or bending, I think that my design could improve the strength of the teeth, the problem I see is that the teeth do not have deep roots, only very shallow ones, look at the layers of teeth how they are laid, if you are going to design a new wheel, create deeper roots of the teeth in the center of the wheel and if the layers were applied in a crisscross pattern, the tooth would be stronger, I am writing from another computer and I do not know if there is a drawing program here, but if so, I will try to draw how I mean it. I also think that full wheel filling will help with higher strength. , my regards Roman---------- P?vodní e-mail ----------
Od: Ryan Harmon via <ryanjharmon1=[email protected]>
Komu: [email protected]
Datum: 21. 3. 2025 21:06:41
P?edmět: Re: [emcoV10lathe] V10P Headstock Fiber Gear Replacement

Hey Roman,

The gear is 0.400 inches thick, I expect that is the nominal dimension. The inner bore is a bit hard to measure because it's been deformed from being pressed onto the splines. The outer dimension of the metal hub seems to be 2.260 inches at the tips of the splines. I just printed a version of the gear with an inner bore of 2.230 inches and it pressed on no problem. Sorry, you'll have to do the metric conversions yourself :)

I plan on uploading cad models and stl files when I have my dimensions set so anyone can reference or print their own if they are so inclined.

Ryan

On Fri, Mar 21, 2025 at 2:34?PM roman fox via <romanfox68=[email protected]> wrote:

Hi Ryan ,could you tell me please ticknes dimension of this gear in milimeters please and what bore diameter has you gear ,thank you Roman
---------- P?vodní e-mail ----------
Od: Ryan Harmon via <ryanjharmon1=[email protected]>
Komu: [email protected]
Datum: 21. 3. 2025 15:01:20
P?edmět: Re: [emcoV10lathe] V10P Headstock Fiber Gear Replacement

I had read something about the hub being splined, but I wasn’t sure what that was going to look like. I just went out to the garage and popped it off, here it is in case anyone has ever wondered?

It’s got a bit of a lip under the spline that was filled with glue, here’s before I peeled it off?

Anyways, these little splines should bite into the plastic as I press it on and I would think hold pretty well. Seems like the glue is more for keeping it from backing off and probably doesn’t need to be too strong?

On Mar 21, 2025, at 8:33?AM, Vedran via <vedran.groups=[email protected]> wrote:

?

hmm.. I might be wrong there about nylon... for some reason I had it in the HDPE and other low surface energy plastics category in my mind, but google says I'm wrong, sorry :(

Regards

Vedran

On Fri, Mar 21, 2025 at 1:44?PM Ryan Harmon via <ryanjharmon1=[email protected]> wrote:

Thanks! I would love to do a video on this, but I have no editing experience, so one step at a time.

I actually didn't know that about nylon and glue, thanks for the heads up.?

I'm not even sure how much it is needed, but I came across this guy selling printed gears for FB-2 mills on ebay:

He recommends using a bead of CA glue before pressing on the gear and notes it is not as much as a press fit.

<image.png>

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I can't imagine CA is providing a ton of strength here, but this guy is recommending it and claims to have had success with a bunch of people.

Maybe a bit of epoxy would work better for the nylon?

On Fri, Mar 21, 2025 at 3:53?AM Vedran via <vedran.groups=[email protected]> wrote:

This is phenomenal, publishing this on youtube or printables or some such place would be quite useful to the community at large.

Regards glueing, remember that Nylon won't stick to most glues

Regards

Vedran

On Fri, Mar 21, 2025 at 2:31?AM Ryan Harmon via <ryanjharmon1=[email protected]> wrote:

Time for an update, I think I've made some good progress and maybe selected my final material.

For my testing, I cobbled together a little rig out of scrap in the garage and a mod 1.5 spur gear I ordered from Amazon. The spur gear has a bar of aluminum pinned to it as a lever and can rotate freely, while the Emco gear or 3D printed gear is pinned in place. I have a bucket on the end of the aluminum bar that I add weights to until a tooth finally snaps.

Here's the setup testing the original gears

<IMG_6237.jpg>

Here's what it looks like for the 3D printed versions

<IMG_6243.jpg>

It's maybe not the most scientific, I wouldn't trust the absolute numbers I'm getting, but I think for a (relatively) consistent comparison, it does the job just fine. I'm using barbell weights to load it up, I have ones as small as 1.25 lbs (.5 kg) up to 10 lbs (4.5 kg). I basically stepped up the weights in increments of 1.25 lbs, which involves a lot of switching out small plates for heavier ones. Since this probably introduces some fatigue, once I've got an initial breaking number, I'll rerun the test starting just below the break point and only add more weight. This has consistently given slightly higher results.

For starters the tufnol was, as the name suggests, quite tough. It really surprised me how much force it took to break, I ended up loading 52.5 lbs (23.8 kg) of weight before it snapped. The break was quite violent as the teeth snapped off very suddenly, no give before that. When I reran the test without any fatigue it got up to 56.25 lbs (25.5 kg).

<image.png>

I started my 3D printed tests with some PLA, as I have plenty and I could work out the kinks before moving on to the other materials. The first test revealed a very critical piece of 3D printing gears, which I learned from one of the youtube videos I watched on the gear tests. The default slicer settings put two perimeter walls on your print, and does infill for the rest. I've highlighted some of the walls in red below so you can see what I mean. My PLA, with 100% infill but just two perimeter walls, failed at 10 lbs (4.5 kg). At this point I was worried the whole thing was going to be pointless, if these gears were just a small fraction of the strength of tufnol it might just break during normal use and put me right back to where I started.

<image.png>

Luckily, reprinting with five walls, gave much better results, with PLA standing up to almost 25 lbs (11.3 kg)

<image.png>

Ultimately, my best result came from a type of nylon, which held up to 52.5 lbs (23.8 kg) putting it just shy of the max I was able to load on the original gears.

<image.png>

My polycarbonate, for whatever reason, just did not perform as well as I hoped. I consistently only got around 35 lbs, well shy of the originals. It also ended up being much more of a pain to print, so I think I've made my decision to go with nylon.

Here is the actual brand:

Screenshots for future ref

<image.png>

<image.png>

<image.png>

A lot of marketing material here, but at least the claims make it sound perfect for the application at hand, and it seemed to stand up to the test.

Anyway, next step is to actually press the old gear off the hub and press/glue this one on. I want to rerun the test with the printed gear on the actual hub, just to make sure it's going to stay put and see if I get the same strength numbers since this setup is a bit different than what I was testing before.

I should have some time to do that this weekend, and if all goes well I might just have a running lathe again ?

On Mon, Mar 17, 2025 at 12:50?PM JM Rall via <=[email protected]> wrote:

Look like emcoshop in Austria advertised the gears made in small batches from time to time. Once you add shipping cost would probably be North of? $400 .

If you went ahead and made a couple You would probably be able to sell some on EBay / Facebook Marketplace

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