Where can I get this gear please?

[John-352932]

Hello, new to the forum so apologies if this has been asked before or if there is a better place to post this.

We have a SR 4-4-0 Schools Class Wellington with a cracked gear on the wheel set. I believe this assembly is part# x9927. I'm talking about the black plastic gear shown in the picture below. It is cracked and spinning on the knurled axle. I have already separated the wheels and axle and I know I'll need to quarter them once put together. This train has pretty much always had problems since the beginning when I bought it for my son years ago and am just now trying to get this part. I feel like I have seen posts saying this part is unavailable now but also feel like I maybe saw some brass replacements?

Appreciate the help in either getting the assembly or gear.

Cheers

John

[Stubaggieboy]

Hi John

I have just had the same problem with one of my King class locos. I failed to find a replacement gear so I purchased a new wheel set from Peterspares. With the postage it cost me around £13.00. Just find the part number from the relevant service sheet.

Regards Stu.

[TVR1707822112]

Hi There!

The parts centres I have been recommended by Hornby customer care are AC Models spares, Lendon's of Cardiff and Peter's spares, have a look at those places. You can probably find the part number on some of the online documentation that is included with the product.

Hope this helps

Best wishes

[atom3624]

If unable to locate an 'original replacement', try Ultrascale.

They have many metal - alloy or brass - direct replacement gears.

These are perfectly formed and a very tight fit.

Word of warning, when removing plastic insert / centred wheels (like Hornby's) be as gentle and keep as straight as possible to ensure they maintain their position when re-quartered.

Al.

[Going Spare]

Unfortunately, Hornby did not offer the gear wheel by itself, just the pack of two replacement wheelsets, which also do not appear to be available from Hornby or any of the major parts suppliers.

If you are able to track down the wheelsets, the pack in malachite green for Wellington is X6109, the wheels in pack X9927 being black. Another possibility is pack X6108 in olive green.

Alternatively, as Al suggests, try the likes of Ultrascale or wait in the hope that someone who knows of a definite Hornby or non-Hornby substitution will respond. Hornby often use common components but given different part/pack numbers for different applications. If not needed, would the gear wheel from your Gordon's wheelset be suitable?

[ColinB]

There was someone on EBay that was selling the gears a couple of months ago when I needed one. I am not sure whether they are still doing them. It is a pure waste to have to buy a new set of wheels just for that gear.

[ColinB]

Here:

https://www.ebay.co.uk/itm/304775763105?hash=item46f60d14a1:g:NNgAAOSwzfNjyVZh&amdata=enc%3AAQAIAAAAwFHwo0xawo%2Fx58CJDH1as%2F5V0Jn7lkEfv2vx9OhlfESzswK4HmTvHjpPZAKFmmslRHaAY4ihVlmOdO6XI5RIY1iMQH5k4XtOnk9FtsGn6Z2oi2Ge2uDO3oULWhWoegXao6pHvWL5L8Xsvj0yK%2BQdwM4x5wXgT50qqTDZdPJAXPmhWT9EDhW9cWCoq7qYhu163dNifLJ6BWeAhOsrHhJU5AoQZlf9uncRVhmpNbSwQIrvSl%2Bvf%2BXyNfMtUHAuLntO5w%3D%3D%7Ctkp%3ABk9SR8TBzMbwYQ

or do a search on EBay for

X8199 L5714 Hornby Spare Brass Worm Gear

[Rog RJ]

Colin, there is no need to paste the whole of the eBay link, just the first part upto the question mark is needed.

Like this https://www.ebay.co.uk/itm/304775763105

Hope you (and others) find this useful to know

[P-Henny]

I knew that Rog and a very useful TIP it is too. Since I can't make my links clickable on my Android tablet, only my PC. The delete everything from the ? onwards is something I do on a regular basis. Never had a problem yet with a link then not being valid after editing.

[ColinB]

Thanks Rog(RJ).

[LesXRN]

I have the same problem on a never run Duchess, split cog. I ordered a new cog from Ultrascale, it's a 21 teeth version in brass, so, count the teeth to make sure you get the correct part.

[John-352932]

Thanks so much for all of the responses and help. My parts diagram only shows the wheel sets assemblies as x9927 which seems to be unavailable and no specific part number for the gear so am finding it hard to find a Hornby replacement.

I do see a gear on ultra scale as referred to as 61xx? Can anyone confirm that would be correct? Correct tooth count and bore size. Only difference that is obvious is the top land on the ultra scale gear.

Would this work? Cheers.

[What About The Bee]

Hello John

Both gears appear to have involute teeth. The issue then, is one of the mesh.

Ignoring the old money terminology of 'diametrical pitch', we have something called 'module'. A module of 1 is one tooth plus one space, along arc at the radius of contact, equal to 3.141593mm. That is pi to 6 places. A module of 1 is equal to pi.

Now small gears will have a corresponding small module. Common sizes are 0.3, 0.4, 0.5 etc. Technically, you can have any module you like, but then you need the cutter, either hob or single tooth type. So given that Hornby isn't investing in custom tooling to protect a spares market they do not maintain, we can assume a common size.

Herein lies the rub. Suppose Hornby have specified module 0.3. That's one tooth plus one space, along the contact line, equal to 0.942478 mm. Now suppose Ultrascale have specified module 0.4 or 1.256673mm. Thats a delta of 0.314159 mm. In old money, that 0.012". Pretty hard to see that in a photograph, given that one is at an oblique angle.

Module 0.4 gear teeth WILL NOT mesh with module 0.3 gear teeth. That is a simple fact of life.

There is a relationship between module and gear diameter (radius) but I do not see this specification of either gear. I do suppose you could measure your damaged gear's overall diameter, but be very aware that this is not the diameter at contact. We can infer the gear module from your measurement. Likewise, you can request the diameter from Ultrascale, again, being very careful to ask for "overall diameter". You could ask Ultrascale for the module directly.

Unless someone has directly tried precisely what you suggest, there can be no answer without further information. If you find some more information, I will be very happy to help you. Alas, I cannot, given the information.

Bee

[What About The Bee]

I should hasten to add:

Pressure angle. The pressure angle if the teeth must also match.

There would be little reason to change the pressure angle from the nominal 20°, so I am working under the assumption that both gears are at 20°. It is quite possible that one company or the other may have used a different angle. Common cutters for involute teeth include 14½° pressure angle.

I do apologize for not including this earlier, yet it is a refinement to the basic module size.

Bee

[John-352932]

Bee

Thank you for the informative post and apologies for not replying sooner. I thought 61xx final drive gear might actually correspond to a part number which someone could confirm would work for my application. It’s a little frustrating that my parts diagram does not even show this gear or a part number for it so it can be replaced with one of matching spec. Thank you for everyones help. Cheers.

[atom3624]

I can definitely vouch for the quality of the UltraScale products - they are excellent.

If in doubt, contact them directly to confirm if you are ordering the correct part.

Al.

[LesXRN]

A bit of an update on this one.

As I mentioned earlier, my unused City of Manchester had a cracked cog which I found after fitting DCC & sound.

I have ordered a cog from Ultrascale and have even found a complete DCC chassis on the bay, just in case.

I also e-mailed Hornby and to their credit, they said they would look into it.

The end result is that in the post today, here at my French home, there was a pack with the complete set of cogs and shaft from them. Many thanks to Hornby.

The interesting thing is that they are for a Merchant Navy, but obviously fit other models.

The part number on the pack is; X8849.

I hope that helps other forum members in future.

Cheers. Les.

[Going Spare]

@LesXRN

If the split gear wheel you are referring to on your loco is the one on the driven wheelset, pack X8849 does not include it (unless, of course, Hornby manually added it before despatch). Assuming your loco is R2856, if you refer to Service Sheet 336C, you will see that while X8849 is the correct pack, it contains only the transfer gears that sit between the motor worm and the gear wheel on the axle: that gear wheel is normally obtainable only by purchasing replacement wheelsets.

[LesXRN]

Hi Going Spare.

Thanks. Here is a photo of the pack just for info'.

Maybe you could have a look and let us know.

Cheers. Les.

[Going Spare]

You appear to have just the standard X8849 pack with two transfer gears, 1 single-stage with a separate spindle and 1 two-stage pre-mounted. These purely carry the drive from the worm on the motor shaft to the gear wheel on the driven axle.

Check the Service Sheet for confirmation. I would normally direct you to the Support menu then Product Support, Service Sheets and Hornby, but sheet 336 and its derivatives is not included in Hornby's listing so go to the Useful Links post pinned at the top of this section of the forum, scroll down to the Service Sheet section and select Lendons of Cardiff.

[LesXRN]

Yes, you're quite right of course. I had a look at the loco whilst waiting for the post to be authorised and saw what you mentioned. It seems a bit daft for Hornby to send the parts that I don't need.

I'm aware of Lendons but might just fit the brass cog that Ultrascale have posted to my daughters in the UK. Failing that, I've got the spare chassis.

Many thanks for your good advice.

Cheers. Les.

[Going Spare]

I hope the Ultrascale gear wheel clears the problem for you.

Without wishing to 'teach grannie......', when separating the wheelset to exchange the gears, try not to rotate the wheel on its axle as the splines on the axle will damage the plastic wheel boss and the wheel may not then be a tight fit when you push it back on to the axle while making sure the quartering is correct at the same time.

[LesXRN]

Thanks G S, that's a good heads up.

[ColinB]

I did find on a Duchess that the wheel gear was the same as one of the transfer gears. So that is probably why Hornby sent you the pack.

[John-352932]

Howdy.

I can confirm that the Ultrascale replacement

Hornby '61xx' final drive gear

Was a good fit for our SR 4-4-0 Schools Class Wellington loco and ran smoothly when turning the motor by hand. Will be putting it on the track tonight to do some final testing.