Making a circlip

[MRA]

Not sure where to put this on the forum - hope here is OK.

I have a very odd job where (for reasons of access and disassembly) I think I need to make a circlip. It will locate a 52mm OD bearing axially, and a 10-tooth 50mm OD pinion has to pass through it on assembly and disassembly. I think I need to make a custom circlip which has 'teeth' filed on the inside, through which the teeth of the pinion will pass - rather like a k-type 'increased abutment' internal clip, but with tabs spaced for this specific pinion's teeth (most k-type clips seem to have 6 tabs).

So the question is - has anyone made them, and what did you make them out of? Making springs is outside my experience so far. This is not a model job but it is at home and does involve machining and, ultimately, an engine And, as usual, there is not much of a budget.

cheers
Mark

 

[BaronJ]

Hello Mark,

With all due respect, I've never seen a circlip with teeth ! Now I have seen a good number of toothed pinions secured with circlips. 50 mm is a quite large diameter for a hobby project, but I've seen much bigger ones !

 

[DJP]

Once you remove material for the teeth that section of the clip will no longer have spring force. The clip may be too weak to be secure. Just a thought.

I'm sure that the people on this forum will take up the challenge. They like to see pictures if you can take some.

 

[Nick Hulme]

Bend a wavy circle from spring wire.

 

[MRA]

I like the wavy circle idea, though I'm not sure it would be strong enough - the bearing clamps down on it with a screwed-ring from the other side.

Here's a pic of some k-type internal circlips. These are 'a thing' - but the 'teeth' are in the wrong place for my 10 tooth pinion.

https://tinyurl.com/y9katqfe

And here are some pics of my problem. In the first two, the shoulder which was meant to locate the bearing, was turned away leaving only 1mm proud (50 ID, bearing seat 52mm ID) to get the big pinion in - which was a modification. This worked OK for years, but in the end the bearing span and there's even less left of the shoulder.

The second two show my latest attempt - cut teeth in the shoulder of a new case, through which the big pinion 'screws in'. This works great, except the case is a more modern version of its predecessor and fouls the pinion where the floor comes closest to it. Floor is only about 4mm thick, and my alloy MIG/TIG skills are appalling - I'm scared to go through. Hence the idea to reclaim the original part with a clever circlip. Pinion's got to go through it - bearing not. Hmm.

Thanks for your help, folks.

 

[TonyM]

Why not use a round wire clip. Set the upturns to the pitch of the gear

You could also use square section

 

[Nick Hulme]

That looks like there is no groove for a circlip?

 

[TonyM]

The groove is 1mm deep. You could go a bit deeper and use a thicker section. As long as the bore is a few thou smaller than the bearing there is no way the bearing will come out. So you could go 2mm deep and use 2.5 square, Or any variation on the theme

 

[Nick Hulme]

How long is the gear?
I've seen split spring steel rings which can be manipulated over/past large items on a shaft, think "Slightly less than one turn of a Slinky", you can get such a thing in nearly anywhere and your only critical dimensions are then ring OD and thickness.

 

[MRA]

Thanks Tony and Nick - Tony, thanks especially for the drawing. I'm afraid personally I'm in the era of conflakes-box-aided-design

The pinion has to come out 'clean' past whatever is locating the bearing, or I'll never get it apart. I think I can make a fixture to hold it in the biggest lathe at work (we lack a face plate, unfortunately) - if I use a 4-jaw I can get it running true however bad my fixture is. So I can cut the groove for a clip.

I thought that a wire clip only 1mm proud might be not enough (hence the exotic circlip ideas), given what happened eventually to the 1mm alloy shoulder I left originally. But - I guess, and thinking aloud - if it locks in and does not spin, then it seems the location should be OK. Even if it locates the chamfer on the very edge of the bearing OD, so much the better - this would force it back into its groove, and I should be able to shim the pinion back to where it needs to be for correct backlash with its crown wheel (this is a 90 deg gear box).

Does this sound right?

(Tony - I was unable to get to the museum today but I emailed the head volunteer who knows where everything is, with your Gardner 3F query. I'll let you know when he gets back to me. You might want to PM me an email address in case I need to forward it to someone at the museum.)


.

 

[BaronJ]

Hi Mark,

It is not uncommon for bearings to be held in place by an adhesive ! In addition you could also fit a thin retaining ring. The Japanese use super glue on bearings all the time ! Yes you have to use heat to remove them, but it works well.

 

[TonyM]

Thanks Tony and Nick - Tony, thanks especially for the drawing. I'm afraid personally I'm in the era of conflakes-box-aided-design

The pinion has to come out 'clean' past whatever is locating the bearing, or I'll never get it apart. I think I can make a fixture to hold it in the biggest lathe at work (we lack a face plate, unfortunately) - if I use a 4-jaw I can get it running true however bad my fixture is. So I can cut the groove for a clip.

I thought that a wire clip only 1mm proud might be not enough (hence the exotic circlip ideas), given what happened eventually to the 1mm alloy shoulder I left originally. But - I guess, and thinking aloud - if it locks in and does not spin, then it seems the location should be OK. Even if it locates the chamfer on the very edge of the bearing OD, so much the better - this would force it back into its groove, and I should be able to shim the pinion back to where it needs to be for correct backlash with its crown wheel (this is a 90 deg gear box).

Does this sound right?

(Tony - I was unable to get to the museum today but I emailed the head volunteer who knows where everything is, with your Gardner 3F query. I'll let you know when he gets back to me. You might want to PM me an email address in case I need to forward it to someone at the museum.)


.

A round section clip will not be forced out by the bearing. As you suggest the radius on the bearing OD will tend to hold it in. If you are less bothered about getting it apart then you don't even need the tabs. 1/2mm proud of the bore is ample to retain the bearing. Try getting a +.020 piston in a standard bore.
Will pm you my email
Thanks
TonyM

 

[john_reese]

Look at the Spirolox retaining ring. Pick one with an ID that will pass the gear. Cut the ring groove to the dimensions given by the manufacturer. https://www.smalley.com/retaining-rings/spirolox

I remember the snap rings used in auto transmissions. They were thicker than a standard retaining ring but had a narrower cross section. Unfortunately they were probably specialty rings made by the tranny builder.

 

[Cogsy]

I was going to suggest a snap ring as well. They're the lowest profile retaining ring I'm aware of (example). If it's just a matter of stopping the bearing from spinning I'd go for a Loctite bearing retainer for ease though.

 

[mu38&Bg#]

Smalley was the first place I checked when I saw the post. Other than Hoopster, there is no ring that fits this application. As already suggested, I think the round wire ring is the easiest to make.

You can't be the only one having this problem. How are others solving it?

 

[LSAGuy]

Cogsy mentioned Loctite as a possible solution, essentially gluing your bearing in place. I've used their press fit assist, thread lockers of all types and porosity fixers to good effect on a variety of projects over the years. You might want to try to find one that suits your project. I've included their pamphlet of their products. However you do it, good luck, sure sounds like a bit of a PITA. :-}

Rick

 

[Mark Duquette]

creating an non serviceable assembly is not a good idea. is there another way to install the bearing and shaft as an assembly from the other side (pressed to a shoulder)?
A sketch of the assembly would help making suggestions.

 

[BaronJ]

Hello Mark,

Whilst I appreciate your concern, using an adhesive to secure a bearing does not make an unserviceable assembly. It is in fact a very common method of securing components ! It only seems to be non serviceable if you don't know how to service it. In this case heat will destroy the adhesive bond and allow bearing removal.

 

[DJP]

This is the Loctite product that I use (green in colour) RC 609.


LOCTITE 609

High strength methacrylate ester acrylic retaining compound designed for the bonding of cylindrical fitting parts.

LOCTITE® 609 is a green, high strength methacrylate ester acrylic retaining compound designed for the bonding of cylindrical fitting parts. The product cures in the absence of air between close fitting metal surfaces. Typical applications include rotor to shafts in fractional and subfractional horsepower motors. Locks bushings and sleeves in housings on shafts. Augments press fits.


Your benefits

 

[BaronJ]

Hi DJP,

Yes ! that is the same stuff I use. Do you notice that the dark green colour fades when it sets.