CNC manufacturing of gears and splined shaft

[gcarmichael]

I've designed a splined prop shaft and gearing for a 15HP outboard engine using Fusion360 (model overview attached). I created this design to replace the standard 2:1 gear ratio with a 1:1 gear ratio. I printed the parts in 3D in PLA to ensure fit and function. I want to have these parts manufactured in 15-5PH Stainless Steel and believe that CNC would be the best method. I've submitted my designs to Xometry and Fictiv for a price quote but both companies have said that they don't have the capabilities to manufacture these parts and ensure strength and functionality. I have done the calculations and verified that all parts are properly designed to support the real world use cases if manufactured in 15-5PH.
This is my first time to use CNC as a production method and I am unsure if I have issues with my designs as far as CNC production goes and who or how I contact a company that can produce the parts for me.
Any guidance on producing this assembly would be appreciated.
Thank you,
Gilbert

 

[memphisjed]

A) Break it down into parts only for xoemetry. Each part is its own job. Do not say what they are for, Hope the parts are good enough.
B) Look for store bought gears, applied technologies sells stuff like that. Quick gear, boston gear, Cleveland gear, many others. As soon as you want good custom gearing your checkbook needs to be bigger than a boat. Same with splines.

 

[Bobw]

What Memphis Jed said.. (Was Tennessee Jed already taken?)

Gears and splines aren't a cheap date, and for the most part, they aren't in the
wheelhouse of most shops.. The people that do GEARS.. Do GEARS...

Not worth trying to reinvent the wheel, make your design around gears that
are available off the shelf.. Even if they need to modified... Cheaper than
starting from scratch.

As for the splines, are they involutes, or just straight? Most any shop with a 4th
axis can give you straight external splines without much trouble, but if they are
involutes or internal, get out the check book.

 

[BT Fabrication]

yes gears are not cheap, had a 2" by 1/2" thick gear quoted in the $1000 or so range for one.

 

[EmGo]

I want to have these parts manufactured in 15-5PH Stainless Steel

That's an interesting choice. No one else would do that, any particular reason why ?

and believe that CNC would be the best method.

CNC what ? Is there a generic CNC machine out there now ? Does milling turning plasma cutting, fries a chicken and packs it all in a box, takes it to the post office ? I bet it's expensive !

This is my first time to use CNC as a production method and I am unsure if I have issues with my designs as far as CNC production goes and who or how I contact a company that can produce the parts for me.
Any guidance on producing this assembly would be appreciated.

If all else fails you could talk to a gear shop. For one or two parts they are most likely NOT going to use a $250,000 cnc hobber or shaper, but oh well.

I disagree that gears have to be expensive. Stick to common sizes and you're talking an hour setup and maybe an hour to cut teeth on little parts like this. Maybe the magic CNC Machine can do it quicker but definitely not cheaper. Magic costs money.

 

[DouglasJRizzo]

Dad used to cut stuff like this on a 1960's Barber-Colman.
Should be a gear house someplace to do this at a reasonable cost.

 

[EmGo]

yes gears are not cheap, had a 2" by 1/2" thick gear quoted in the $1000 or so range for one.

BT, that's ridiculous. Unless there's something you're not telling, like it's made out of gold, we're talking $250 max. Next time send me a pm.

 

[mhajicek]

BT, that's ridiculous. Unless there's something you're not telling, like it's made out of gold, we're talking $250 max. Next time send me a pm.

One of anything is expensive. Unless it's a repeat job, I have a minimum of $400 + materials. $250 hardly covers the time to quote, plan, order and receive stock, and do paperwork, before we even get into making anything.

How many hours of labor can you get done at your auto repair place for $250?

 

[EmGo]

Unless it's a repeat job, I have a minimum of $400 + materials.

Everyone has their own philosophy, but this attitude may be partially responsible for the fact that manufacturing in the US is a minor niche category.

$250 hardly covers the time to quote, plan, order and receive stock, and do paperwork, before we even get into making anything.

In that case, BT will be a lot better off giving me a call next time he needs teeth ... plus I actually know something about it. Is that included in your $400 setup charge ?

How many hours of labor can you get done at your auto repair place for $250?

Why think small ? What does Camille Vasquez charge ? Or Lloyd Blankfein ? Hell, Larry Whatsisname from Oracle, what the hell does he know ? $5,000 an hour sounds reasonable to me !

 

[memphisjed]

I know Marcus might gringe but you can do prototyping gears good enough for this on a Bridgeport cnc with a fourth. This is back to op, good enough can be had with xeometry, what your definition of good enough is would be deciding factor.
Questioning their response on not having capabilities, they are like Uber- they do not have them in house. Well, a few things like plate/material processing, but not machining.

 

[maguilera]

From my experience in Brazil, as long as the gear is designed using standard parameters such as module, pressure angle, tooth form, quality class and so on... they are relatively cheap.

Obviously, this only applies if the gear is not very large nor very small.

I had a case in my previous job where they required a rather large pinion (Øext≈1400mm) with a non-standard module and long addendum tooth form, it turned out to be quite expensive and time consuming to manufacture.

Cheers

 

[Ries]

If Goldstein Gears is really that cheap, I predict a lot of orders. Last time I needed ONE custom gear was in about 2001. I had the gear shop in the industrial part of Seattle make it, and it was about $1200. Thats 2001 dollars. They used 50 year old non CNC machines. It was about 6” in diameter, maybe 40 teeth. My guess is they cost more now. Everything else does.

 

[EmGo]

If Goldstein Gears is really that cheap, I predict a lot of orders.

Goldstein Gears really is that cheap, he's been known to cut 67* helicals on Rotax cams for $3.50 apiece or a 16" diameter timing gear for a nordberg diesel from a custom forging for $1500. Unbreaking pump shafts for the coast guard were $100 each, complete clutches for xr harleys were $150. Prices were always a little low but I survived ok for 25 years until the US felt compelled to invade another country that hadn't done a damn thing to them/us/it and I'd had enough.

Yeah, feel free to pm for quotes, I can still get real teeth cut for reasonable prices, either in the US or abroad, and all this stuff of "you can approximate the shape by having a beaver gnaw it" is so unnecessary. Real gear shops do this stuff all the time, for reasonable prices.

Last time I needed ONE custom gear was in about 2001. I had the gear shop in the industrial part of Seattle make it, and it was about $1200. Thats 2001 dollars. They used 50 year old non CNC machines. It was about 6” in diameter, maybe 40 teeth.

Roland Randberg (sp ? and my memory for names has never been great) at Seattle Gear/ the Gear Works was famous for being a giant free-ranging dildo. The only reason anyone who knew anything went there was because they could cut large accurate worms. Everything else was better somewhere else. And to prove it, when he retired he fucked over all the guys who'd worked there for thirty years or so. Rush Gear is another to avoid, btw.

There's some lumps of rotten meat in the gear shop stew, just like in every field. But most places are ok, and some are really nice. There's a couple good ones who post here, even. Altho not as cheap as me

btw, I sure do read some nonsense conjecture about gear cutting in this place. Some of it is as ridiculous as me talking about flying a 747. Maybe if you don't know about a subject, no need to post silly suggestions ?

 

[EmGo]

I had a case in my previous job where they required a rather large pinion (Øext≈1400mm) with a non-standard module and long addendum tooth form, it turned out to be quite expensive and time consuming to manufacture.

Sorry for two posts where one would do, but using the phone sucks. Maguilera, that's even not so bad these days if you have the right tools. If you could make me 25 again I'd buy the right stuff in the first place instead of going through dozens of hobbers and shapers to figure out what's best Again, for oddballs feel free to pm, may as well put 50 years of experience to use in the cause of fighting unreasonable prices

ps 1400 mm isn't so large, the stuff we've been doing the past few years generally runs about 3 meters. Can go to 5. Ground teeth if you like.

On the other end, one friends shop can only go 400 mm for ground teeth -- but have friends in US who are adept at small teeth. None of them charge $400 for a quote or $1200 for a crummy little 6" gear.

 

[BT Fabrication]

BT, that's ridiculous. Unless there's something you're not telling, like it's made out of gold, we're talking $250 max. Next time send me a pm.

yep no joke, lowest quote was in the $800 range for a helical angle cut gear. was a powder metal gear that didn't exist anymore and had cracked from a bad production or something and the machine never ran and nobody knew why. id was a press fit bore of about 1.420 or so and od of about 2" and that small but damn crazy expensive to machine.

 

[Ries]

Since that money was spent in 2021, and the lathe the gear went on runs just fine, my amortized cost is long forgotten.
But if there are, indeed, such cheap gear shops out there, by all means, post names and addresses or websites.

I have had to remake off the shelf gears a couple of times for my old Yanmar Tractor, actually hand filing the internal 13 point spline drive on an 80s japanese designed gear, after I milled the height to size, because there was no stock of anything like it in the USA, and custom new gear quotes, were, again, in the thousand dollar plus range. Everybody I know who has needed custom gears has paid big bucks- evidently these cheap gear shops are extremely hard to find.

 

[EmGo]

But if there are, indeed, such cheap gear shops out there, by all means, post names and addresses or websites.

I have referred people here, who were being fed large quantities of bullshit by supposedly knowledgeable people. I loved the one where one guy insisted the necessary first step was drawing a circle in CAD for $600. I sent him to a friend, the entire job was less than that, for a one-off single enveloping wormgear.

But thanks, think I'll stick to pm's, some people asking here are riffraff, not worth wasting the time on. This thread is possibly in that category. OP might want to just cnc his teeth. Or he may have a brain hidden behind the buzzwords, hard to tell from one post.

I have had to remake off the shelf gears a couple of times for my old Yanmar Tractor, actually hand filing the internal 13 point spline drive on an 80s japanese designed gear, after I milled the height to size, because there was no stock of anything like it in the USA, and custom new gear quotes, were, again, in the thousand dollar plus range. Everybody I know who has needed custom gears has paid big bucks- evidently these cheap gear shops are extremely hard to find.

Like I said, send a pm. One thing true about gears is, there's a bigly range of possibilities, and seems like people in general are not good at discriminating between a hypoid and a spur gear. But, given available information , the prices you are talking are ridiculous.

On the other hand, a friend just called me to rage against the machine. He just paid $2.39 for a potato. Maybe it was gold-plated ? The US is vastly fucked up, and that's not a political statement. Prices are beyond crazy.

 

[pat pounden]

Since that money was spent in 2021, and the lathe the gear went on runs just fine, my amortized cost is long forgotten.
But if there are, indeed, such cheap gear shops out there, by all means, post names and addresses or websites.

I have had to remake off the shelf gears a couple of times for my old Yanmar Tractor, actually hand filing the internal 13 point spline drive on an 80s japanese designed gear, after I milled the height to size, because there was no stock of anything like it in the USA, and custom new gear quotes, were, again, in the thousand dollar plus range. Everybody I know who has needed custom gears has paid big bucks- evidently these cheap gear shops are extremely hard to find.

wasn't an iseki (or same w/ diff badge)tractor was it??-just got through working doing same stuff-the 13 spline was approx 15/16 just slightly bigger than a 7/8 13 spline that existed!!-real nuisance and NONE available

 

[triumph406]

I used to use a gear shop in Costa Mesa (not going to mention the owners name to a avoid a PM from EG) who did some work for me years ago, maybe 10-12 years.

It was to make 2 disks with internal splines, and 6 disks that had external splines that had to be a tight slip fit into the internal splines. The external splines also had to have a lead to help with engagement. We supplied the material and the $'s. I told the owner I don't care what type of spline you use, it has to have this number of teeth and be a slip fit, that's all I care about. The end result was a perfect fit, and I think we paid $1000

Find the right place, talk to the owner, establish a rapport, and likely you can get the job done for a reasonable price. Assuming you know what a reasonable price should be, a lot of people don't

 

[Ries]

wasn't an iseki (or same w/ diff badge)tractor was it??-just got through working doing same stuff-the 13 spline was approx 15/16 just slightly bigger than a 7/8 13 spline that existed!!-real nuisance and NONE available

Nope, mine is an actual legally imported (not gray market) Yanmar diesel. One of the things I found out in trying to source the gear was that Japan has more than one gear standard, and due to the extreme age of my tractor, it was a much less common gear, even in Japan.
I ended up buying a gear that had a single keyway cut in the center hole, then milling 13 round notches on the rotary table, and then hand filing each notch into a female spline shape.
Twice.
My kid destroyed my first repair gear after a few years, bush hogging logs or something.
So I did it again.
Went faster the second time.