Chain case/ chain guard

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fastpedaller
Posts: 3435
Joined: 10 Jul 2014, 1:12pm
Location: Norfolk

Re: Chain case/ chain guard

Post by fastpedaller »

As promised.... a small update on my project to make a chaincase using GRP (glass reinforced plastic, or 'fibreglass') for the On-One Pompino.......
Having made a cardboard mock-up, I made a female mould using a piece of contiboard. With a 'chaincase -shaped' plastic barrier held (just about) in place using wooden block and gaffer tape, a 1/4 inch ball bearing was used to make a small plasticene radius at the join. Photos show the part after gelcoat and layup of 2x 1oz/sq ft chopped strand mat and resin. Once I've removed this part from the mould I'll make some holes and cuts to enable a trial fitment of the top part. I'll use some tubes moulded from GRP to fix the top part to the seat tube, downtube, and seatstay using releasable cable ties. This is to make it easy to remove in the event of a P*******. The difficult part will be attaching the lower section and making it both rigid and easy to remove. I'll then need to do some more moulding to make a 'closure panel'. Once I've fitted the top part, I'm confident the inspiration of how to achieve my goal will follow :idea:
Attachments
chaincase2.JPG
chaincase1.JPG
Jamesh
Posts: 2963
Joined: 2 Jan 2017, 5:56pm

Re: Chain case/ chain guard

Post by Jamesh »

Maybe if you made another one a couple of mm smaller or larger in diameter you could put them inside one another and use self tapping screws to secure.

Cheers James
fastpedaller
Posts: 3435
Joined: 10 Jul 2014, 1:12pm
Location: Norfolk

Re: Chain case/ chain guard

Post by fastpedaller »

My plan is to make a second part using the same mould, but just the basic flat shape (ie no rim). After I've trimmed the rim of the part in the photo, such that it's an accurate width (yet to be decided) I will then laminate parts of the second part to the first. This will give a 'top part of the chaincase' which will be a U section, similar to some commercially available.
9494arnold
Posts: 1208
Joined: 21 Jan 2007, 3:13pm

Re: Chain case/ chain guard

Post by 9494arnold »

I considered a chain case on a fixed but decided it was too much of a faff.
( I had one but it was too long)
What I did do was use a back Mudguard on the front, took the adjustable bracket off and riveted a front Mudguard bracket on, then cut it as low as I dare ( a good couple of inches lower than a standard front guard) and added a mudflap too.
Even kept the reflector.
Extra length in front of the fork crown too.
I considered ( again but a bit of a faff) vinyl filler between the Chainstay and the seatstay at the rear, particularly on the chai side, and between the Mudguard stays in the front perhaps.
Jamesh
Posts: 2963
Joined: 2 Jan 2017, 5:56pm

Re: Chain case/ chain guard

Post by Jamesh »

fastpedaller wrote:My plan is to make a second part using the same mould, but just the basic flat shape (ie no rim). After I've trimmed the rim of the part in the photo, such that it's an accurate width (yet to be decided) I will then laminate parts of the second part to the first. This will give a 'top part of the chaincase' which will be a U section, similar to some commercially available.


Do you not want a fully enclosed chain?

Top only enclosure seem a bit half baked???

Cheers James
fastpedaller
Posts: 3435
Joined: 10 Jul 2014, 1:12pm
Location: Norfolk

Re: Chain case/ chain guard

Post by fastpedaller »

Jamesh wrote:
fastpedaller wrote:My plan is to make a second part using the same mould, but just the basic flat shape (ie no rim). After I've trimmed the rim of the part in the photo, such that it's an accurate width (yet to be decided) I will then laminate parts of the second part to the first. This will give a 'top part of the chaincase' which will be a U section, similar to some commercially available.


Do you not want a fully enclosed chain?

Top only enclosure seem a bit half baked???

Cheers James

Absolutely! - that's why I'm making my own. The description above is for 'section #1' of the project. Section #2 will be a lower part, which is envisaged to be similar to the top, and attaching to the top (that's the tricky bit) - If I'm able, attachment for both to the chainstay will help steady everything up. There will then be a third, flat piece joined to both the earlier parts, again using releasable cable ties. So, yes, it's as near to fully enclosed as I can get. In addition to protecting the chain, my aims are to make it easily removable without tools, and using as few 'pieces' as possible, and using no metal parts likely to damage the paint on the frame - a challenge, but one I'm willing to try.
rjb
Posts: 7200
Joined: 11 Jan 2007, 10:25am
Location: Somerset (originally 60/70's Plymouth)

Re: Chain case/ chain guard

Post by rjb »

Here's an alternative idea. I bought some flexible slit cable conduit from a motor factors. Ran it for a couple of years on the crossover drive on the tandem. It kept most of the dirt out, the oil in. Single speed or hub gear only. No good for those dedanglers. :D
viewtopic.php?t=104164
At the last count:- Peugeot 531 pro, Dawes Discovery Tandem, Dawes Kingpin X3, Raleigh 20 stowaway, 1965 Moulton deluxe, Falcon K2 MTB dropped bar tourer, Rudge Bi frame folder, Longstaff trike conversion on a Giant XTC 840 :D
fastpedaller
Posts: 3435
Joined: 10 Jul 2014, 1:12pm
Location: Norfolk

Re: Chain case/ chain guard

Post by fastpedaller »

Hmm - I'm surprised it's flexible enough to go around the chainrings, and I think it would struggle with a 20T sprocket, but fair play for trying it. As it happens, I'm also into kit cars, and have quite a collection of the split conduit because I use it on my cars. If you are in Norfolk ( otherwise postage would be prohibitive?) you are more than welcome to some if I have 2m of 10mm I/D..
Here's a link I've found for buying it by the metre
https://www.altecautomotive.co.uk/condu ... 1244-p.asp
Fastpedaller
fastpedaller
Posts: 3435
Joined: 10 Jul 2014, 1:12pm
Location: Norfolk

Re: Chain case/ chain guard

Post by fastpedaller »

Here's the latest instalment of the 'chaincase build'
Some GRP tubes were made, including tube sections to attach to the down tube and seatube. The downtube and seatube parts were moulded around suitable size tube, with a piece of old inner tube in place, thus making them a slightly larger diameter. This means that (with the addition of inner tube to protect the paint) they mount onto the tubes using releasable cable ties.
The photos just show the 'top half' of the chaincase and the lower half is still in construction. In fact the lower half has already been cut and rejoined, because I tried making the upper part larger (ti include more of the 'chainring bit' unsuccessfully.- A cardboard pattern is a help, but its additional flexibility compared with GRP can be deceptive. :? It's all been made deliberately oversize to give good clearance and also allowance for changes to sprockets and chainring
It looks a bit ragged around the edges because I haven't done final trimming.First photo has inverted for some reason?
chaincase3.JPG[/attachment]
chaincase4.JPG
chaincase5.JPG
Attachments
chaincase3.JPG
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