Author Topic: Spiral Bevel Gears  (Read 9986 times)

Offline Joules

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Spiral Bevel Gears
« on: March 20, 2018, 11:49:09 AM »
Anyone come across some cheap/scrap equipment that might be fitted with these type gears.  I need a 12mm bore through them, it doesn’t matter if the bore is smaller as long as they have enough meat to be machined to that size.  To buy gears on their own is horrendous, but these days mass produced items sometimes have hidden gems inside them.  The final use is to drive an ER-11 collet spindle, so not huge torque, however metal gears prefered.  I will be testing my idea with printed gears first, but only for running the spindle...  NOT cutting.

      Cheers
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Offline awemawson

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Re: Spiral Bevel Gears
« Reply #1 on: March 20, 2018, 12:14:52 PM »
Loads on eBay as spares for Angle Grinders - just pop in the search 'spiral bevel gears'

Here is just one example
Andrew Mawson
East Sussex

Offline Joules

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Re: Spiral Bevel Gears
« Reply #2 on: March 20, 2018, 12:21:29 PM »
Thanks Andrew, I should have said 1:1 or 1:1.5  I have a varied collection of angle grinder gears that got used in model heli gearboxes.  I will give ebay a go.

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Offline awemawson

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Re: Spiral Bevel Gears
« Reply #3 on: March 20, 2018, 01:01:20 PM »
There is always HPC Gears if you are feeling rich  :ddb:


http://www.hpcgears.com/n/products/3.bevel_gears/bevel_gears.php

Andrew Mawson
East Sussex

Offline Joules

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Re: Spiral Bevel Gears
« Reply #4 on: March 20, 2018, 01:25:45 PM »
I think Rich would need more than a feel for a set of their gears  :(  and they are only down the road some, from here.
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Offline tom osselton

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Re: Spiral Bevel Gears
« Reply #5 on: March 20, 2018, 05:03:06 PM »
Just wondering what these would be used in or where they would be repaired I think I'd try someones shop bin.

Offline Joules

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Re: Spiral Bevel Gears
« Reply #6 on: March 20, 2018, 05:18:22 PM »
Tom, I have been looking up industrial sewing machines, internal components for motorbikes and small engines.  They are used in milling machines, where you have a horizontal or vertical conversion head.   Basically what I am trying to do here, I could use straight cut bevel gears but they would be noisy and prone to vibration.

Keep looking and see what junk turns up, I can print gears, just wish 3D printing in metal was as easy.

Might even have to re think my plan as it’s do able in a few ways.
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Offline PK

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Re: Spiral Bevel Gears
« Reply #7 on: March 20, 2018, 06:28:06 PM »
I'll second angle grinders. you even get a case with an output bearing....
PK

Offline chipenter

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Re: Spiral Bevel Gears
« Reply #8 on: March 21, 2018, 03:57:19 AM »
I may have some from a mobility scooters diff , will have a measure tomorow as I am out today .
Jeff

Offline Joules

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Re: Spiral Bevel Gears
« Reply #9 on: March 21, 2018, 06:47:55 AM »
Thanks Jeff, I took a look at mobility transaxle parts.  Most of the diffs I saw use straight cut bevel gears, but the searches did pull up India for sprial bevel gear sources.  The main drive gear in mobility transaxles are helical gears and look very meaty, will keep that in mind for the future.

        Cheers
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Offline AdeV

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Re: Spiral Bevel Gears
« Reply #10 on: March 21, 2018, 04:00:41 PM »
I'm no expert in gears but... could you buy 2x sets of matching angle grinder gears, and just use the small (or large, if you've got room) pair? That'd give you 1:1 wouldn't it?
Cheers!
Ade.
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Offline Joules

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Re: Spiral Bevel Gears
« Reply #11 on: March 21, 2018, 04:09:34 PM »
LOL if only, the gears aren’t at 45 degrees, so they don’t meet at a right angle.
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Offline AdeV

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Re: Spiral Bevel Gears
« Reply #12 on: March 21, 2018, 04:40:08 PM »
Bugger, I knew it was too good to be true...

Cheers!
Ade.
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Offline Joules

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Re: Spiral Bevel Gears
« Reply #13 on: March 21, 2018, 05:04:52 PM »
The other slight fly in the ointment is that the matching gears need to be a mirror image of each other, so two large flat gears will have opposing spiral directions when brought together.   If you look closely the pinion spiral is going opposite way to the larger wheel.  Tons of subtlety in this gear making malarkey.

Being able to 3D print gears is a great teaching aid, but when it comes to making them... Wow, watch some of the YouTube videos on spiral bevel gear making...  Fascinating.
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Offline PK

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Re: Spiral Bevel Gears
« Reply #14 on: March 22, 2018, 07:44:36 AM »
 I once owned an indexing head. A mate 'borrowed' it and it ended up on his mill hobbing gears.


Sadly I don't have any pics of it, but we later got Y slaved to X and, with the indexer at an angle, were able to cut helicals. 

You think that the maths bends your head, then you look at the calculations needed to cut just about anything on a manual hobbing machine and realise that this CNC lark isn't so bad..
PK

Offline efrench

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Re: Spiral Bevel Gears
« Reply #15 on: March 22, 2018, 01:25:20 PM »
How did the printed gears work?

Offline Joules

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Re: Spiral Bevel Gears
« Reply #16 on: March 22, 2018, 01:45:21 PM »
They are only used to position and test parts fit.  I can try combinations of parts and ideas, such as the spindle housing.   I don’t yet have any final gears for the finished head, so that is dictating my design.
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Offline kayzed1

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Re: Spiral Bevel Gears
« Reply #17 on: March 22, 2018, 02:05:10 PM »
I will look in my scrap box tomorrow for you as i think i have a gear or three in it..
Lyn.

Offline chipenter

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Re: Spiral Bevel Gears
« Reply #18 on: March 22, 2018, 03:15:58 PM »
An alturnative is to use two sets of angle grinder gears lock the pinions to a shaft  , but you will loose power driving the first pinion .
Jeff

Offline Joules

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Re: Spiral Bevel Gears
« Reply #19 on: March 22, 2018, 03:57:14 PM »
This is all on the little SU1 mill.  I am fed up swapping the motor and spindle around.  In horizontal setup the speed is too high, so am making new pulleys to halve the spindle speed.  The plan then was to run a second belt to a line shaft in the overarm and drive a much smaller ER11 vertical spindle at higher speed.  This is where the spiral bevel gears come in, I have machined a new boss that fits where the old vertical did and it is bored to take a 10mm shaft.  The arrangement will be something like a miniature Schaublin 13 mill.  I can develop and 3D print the vertical head casing before fabricating it in alloy.  I also have a vague notion that the line shaft through the over arm can be used to power other accessories like a slotting head.

Oh, nearly forgot, thanks to everyone for the offers of help.

The motor has recently had a couple of hiccups and snapped an end mill.  I am looking at replacing the motor and speed controller with an industrial sewing machine servo motor.  They are compact, reliable and cheap.  Very good option for a Mini lathe refit.
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Offline RussellT

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Re: Spiral Bevel Gears
« Reply #20 on: March 23, 2018, 05:11:08 AM »
This has been bugging me since you first posted it, but I have finally remembered another source of spiral bevel gears.  They can also be found in the gearbox at the bottom of outboard motors.  I'm fairly sure I have the gears from a 6hp motor somewhere.  I'll try and dig them out later today to check on the ratio.

Russell
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Offline Joules

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Re: Spiral Bevel Gears
« Reply #21 on: March 23, 2018, 09:32:56 AM »
That is good to know Russell, suspect the gears might be a tad large for my little mill.  Would still be interested to have dimensions though, bet someone else would also have a use sooner or later.
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Offline RussellT

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Re: Spiral Bevel Gears
« Reply #22 on: March 23, 2018, 12:15:48 PM »
Here are a couple of pictures.  The ratio is 26:15 or 1.73:1

Russell
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Offline Joules

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Re: Spiral Bevel Gears
« Reply #23 on: March 23, 2018, 01:25:21 PM »
Mmmmm, the ratio is workable and size smaller than I imagined.  This does look promising...

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Offline kayzed1

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Re: Spiral Bevel Gears
« Reply #24 on: March 23, 2018, 01:34:12 PM »
Sorry the gears i thought i had have gone walkabout..
Good luck.
Lyn.

Offline Joules

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Re: Spiral Bevel Gears
« Reply #25 on: March 23, 2018, 01:42:04 PM »
Thanks Lyn, I am hoping the gears from Russell might do the job.  Good to know a source of gears from outboard motors.
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Offline AdeV

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Re: Spiral Bevel Gears
« Reply #26 on: March 23, 2018, 06:56:52 PM »
If you end up needing another set, I think I also have a couple of old outboard gearboxes kicking around. Whether I can FIND them or not, remains to be seen...!
Cheers!
Ade.
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Offline Joules

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Re: Spiral Bevel Gears
« Reply #27 on: March 23, 2018, 07:19:05 PM »
That would be very welcome Ade now I think these are a viable option.
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Offline Joules

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Re: Spiral Bevel Gears
« Reply #28 on: April 14, 2018, 12:37:53 PM »
I managed to pay RussellT a visit this afternoon.  Bit of a natter and collect the gears he had found for me.   Got a bit more than just the two gears, the rest of the shaft and the reversing gear.  I didn’t know that was how they reversed the prop on an outboard by sliding a selector to pick one of the two bevel gears.   Anyhow, this looks a great place to start for the milling head.

If anyone is interested Russell kept the prop and we recon it would be a good basis for a home made twin tube, should anyone be so inclined.

 :dremel:

       Cheers Russell
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Offline Joules

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Re: Spiral Bevel Gears
« Reply #29 on: April 20, 2018, 03:06:42 PM »
And, for my next dodgy trick, machining the gear to fit on the ER11 spindle.   The gears are really nice and VERY hard.  When you think of their working enviroment, thick grease and 6hp into a prop they need to be tough.

The setup for machining the gear isn’t great, but for one gear I didn’t really want to make a carrier to support the gear.  I clocked it true gripped in the jaw teeth, it needed a little heavier cut than I was happy with to break the surface but machined OK after that.   Well until the last cut when I was under dimension, then over dimension by 0.04mm, gibs not tight enough I think.

I will grind a recess on the spindle to take some stainless shim that will pack the gear to a tight fit, the gear will also be keyed onto the spindle.   You can see the RIZZLA paper shim gives me a tight fit, by using a recess it will trap the thicker shim on the spindle.

« Last Edit: April 20, 2018, 05:29:35 PM by Joules »
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