Author Topic: Spiral Bevel Gears (Read 26805 times)

Joules · « **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

awemawson · « **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

Joules · « **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.

awemawson · « **Reply #3 on:** March 20, 2018, 01:01:20 PM »

There is always HPC Gears if you are feeling rich

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

Joules · « **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.

tom osselton · « **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.

Joules · « **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.

PK · « **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

chipenter · « **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 .

Joules · « **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

AdeV · « **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?

Joules · « **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.

AdeV · « **Reply #12 on:** March 21, 2018, 04:40:08 PM »

Bugger, I knew it was too good to be true...

Joules · « **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.

PK · « **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

efrench · « **Reply #15 on:** March 22, 2018, 01:25:20 PM »

How did the printed gears work?

Joules · « **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.

kayzed1 · « **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.

chipenter · « **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 .

Joules · « **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.

RussellT · « **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

Joules · « **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.

RussellT · « **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

Joules · « **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...

kayzed1 · « **Reply #24 on:** March 23, 2018, 01:34:12 PM »

Sorry the gears i thought i had have gone walkabout..
Good luck.
Lyn.

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Author Topic: Spiral Bevel Gears (Read 26805 times)