Making a better felt filter for the oil tank

Helpful information and requests for assitance and advice
Member
User avatar
Posts: 179
Joined: Tue Nov 29, 2005 8:51 pm
Location: Herts UK

Re: Making a better felt filter for the oil tank

Postby Group Leader » Wed Feb 06, 2019 9:53 pm

Ah, all is revealed, thanks Ron!

I take the point about the possible lack of need for a filter but I think it must be better with one providing, of course, that the warnings regarding hole blocking potential are noted and also care taken to ensure the new version is not too restrictive and adequate flow is maintained.

If I can get hold of the necessary materials I might have a go at it and if it doesn't come to anything I've still got the original and it might be an interesting exercise.

Alan
1953 AJS 16MS and a 1/3 scale Sopwith Triplane but that's another story ..... :lol:

Member
User avatar
Posts: 1071
Joined: Wed Oct 12, 2005 9:45 pm
Location: CO DURHAM UK

Re: Making a better felt filter for the oil tank

Postby REW » Thu Feb 07, 2019 9:52 am

Agreed Alan!
Ron

1951 Matchless G3L, thumping round the Durham Dales

Member
User avatar
Posts: 179
Joined: Tue Nov 29, 2005 8:51 pm
Location: Herts UK

Re: Making a better felt filter for the oil tank

Postby Group Leader » Mon Feb 11, 2019 9:52 pm

In anticipation of the arrival of the mesh (the felt turned up today from the company that Ron used - excellent service and cheap to boot!) I've done a drawing showing the dimensions as measured from my original.

Sorry, it was more convienent to use metric measurements (I'll have to be sacked) and the drawing is not to BS, sorry ISO standards nevertheless it should be enough if anyone else wants to give it a go. The eagle eyed amonst you will note that the ID of the felt bore is smaller than the OD of the ends - (2x the thickness of the mesh + 4x the thickness of the felt). I have no explaination as to why this should be other than to suggest that either the thickness of the unconstrained felt has swelled over the last 60 years or maybe that the main felt tube is actually a double thickness of felt or the difference is the effective thickness of the woven mesh (rather than just the wire thickness). As I have no intention of dismembering my original it will have to remain a mystery at least for now. My intention is to make the felt tube a good fit within the ID of the mesh and sizes will be chosen accordingly.

Filter Drawing 600 pix.jpg


No guarentee is implied or liability accepted blah, blah, blah. Use it entirely at your own risk ....

Alan
You do not have the required permissions to view the files attached to this post.
1953 AJS 16MS and a 1/3 scale Sopwith Triplane but that's another story ..... :lol:

Member
User avatar
Posts: 179
Joined: Tue Nov 29, 2005 8:51 pm
Location: Herts UK

Re: Making a better felt filter for the oil tank

Postby Group Leader » Thu Feb 14, 2019 8:57 pm

At some point then I'll have to give it a try!

Filter Materials.JPG
You do not have the required permissions to view the files attached to this post.
1953 AJS 16MS and a 1/3 scale Sopwith Triplane but that's another story ..... :lol:

Member
User avatar
Posts: 1071
Joined: Wed Oct 12, 2005 9:45 pm
Location: CO DURHAM UK

Re: Making a better felt filter for the oil tank

Postby REW » Thu Feb 14, 2019 11:34 pm

I watch with intense interest! It is the disparity between the ID of the felt in the bore and the OD of the wrap around ends that gave me pause for much thought. I haven't taken my kindly donated original apart to see what shape the felt was originally cut to, but therein, I think, lies the answer...

Good luck!
Ron

1951 Matchless G3L, thumping round the Durham Dales

Member
User avatar
Posts: 179
Joined: Tue Nov 29, 2005 8:51 pm
Location: Herts UK

Re: Making a better felt filter for the oil tank

Postby Group Leader » Fri Feb 15, 2019 9:39 pm

Thought I'd do an experiment to try and make a felt liner.

It just so happened that I had a bit of stainless steel tube 24mm diameter kicking around in the workshop which was rather handy as that is the OD of the filter mesh! So that would make an excellent substitute former. So as not to waste too much material first time around I decided to just make a short length of felt tube so a rectangle of felt was cut ~60mm long by 75mm wide. 75mm is just short of the circumference of the 24mm tube.

When rolled into a tube the thickness of the felt created an overlap of ~ 3mm which was just about ideal. The seam was sewn (rather poorly, I'm an engineer not a tailor!) with cotton and the end which would ultimately be turned over was stitched around the edge to stop the two layers seperating from the last true stitch. This produced a felt liner that was a snug fit in the stainless tube.

The liner was positioned in the tube with a generous overhang. Although I didn't measure it there's probably ~ 5mm length consumed by the rolling it back on itself and I had about 12mm fold back along the tube. Becuse the liner didn't emerge from the other end as a "proper" one would there was nothing to hold on to to retain the felt from moving when rolling the end back. So, I cheated and super glued the felt in the correct starting position making sure as I did so that none of the glue wicked up the felt to the bit that would be rolled back.

The felt hanging out of the end was then briefly steamed over the output from a kettle to slightly moisten and warm the felt (I live relatively close to a town once renowned for making felt hats and I've seen a programme that described how the felt was steamed before being forced into shape over heated moulds when making them ......). The felt was then coaxed back on itself, starting at the seam and supporting the seam as the rest was folded back on itself.

When doing it for real, I'd use some proper, thick button thread and I think you need to use a curved needle as access to the inside of the tube will be tricky in the middle.

Anyway, for a first go I think I will claim success, it was all very easy really!

It's too late to go and start chopping up steel mesh, that can wait for another day.

First Filter Experiment (1).JPG


First Filter Experiment (2).JPG


First Filter Experiment (3).JPG
You do not have the required permissions to view the files attached to this post.
1953 AJS 16MS and a 1/3 scale Sopwith Triplane but that's another story ..... :lol:

Member
User avatar
Posts: 1071
Joined: Wed Oct 12, 2005 9:45 pm
Location: CO DURHAM UK

Re: Making a better felt filter for the oil tank

Postby REW » Sat Feb 16, 2019 10:25 pm

Looks like a result. The stainless pipe is thin; my mesh "tube" ends are somewhat thicker so I intend to sow the felt join so that there is a bit of a flare in the final bit that rolls over the mesh end.

Looking at the original felt lined filter the sowing seems to be felt edge to felt edge, a bit like a surgeon would - well beyond my capabilities.
Ron

1951 Matchless G3L, thumping round the Durham Dales

Member
User avatar
Posts: 179
Joined: Tue Nov 29, 2005 8:51 pm
Location: Herts UK

Re: Making a better felt filter for the oil tank

Postby Group Leader » Sun Feb 17, 2019 9:31 am

REW wrote:Looking at the original felt lined filter the sowing seems to be felt edge to felt edge, a bit like a surgeon would - well beyond my capabilities.

I agree Ron that that the original does look to be sewn edge to edge and that was my original intention to try but when I tried the felt in the tube it was clear that I'd not reduced the overall width sufficiently to allow for the thickness. It's 40+years since I did any proper sheet metal work with bend allowances etc and I'm not certain felt behaves the same anyway hnce resorting to the "suck it and see" overlap. Perhaps I'll have another go and see if I can do it properly.

With regard to having a bit of a flare on the ends. I'm not sure that you can - fundamentally we are making a compound curved 3D object out of a 2D sheet so there's actually got to be some stretching and compression in the material. Presummably, non-woven felt is actually very good at this given suitable mechanical encouragement. If you do incorporate some extra material it can only be at either end so the material would need to relocate around the circumference rather than just radially.. Who knows? Maybe another experiment required.

Wouldn't it be great if somone could stumble on the original manufacturing drawings and instructions in the back of a shed draw somewhere ....... ?

Anyway, another interesting challenge.

Alan
1953 AJS 16MS and a 1/3 scale Sopwith Triplane but that's another story ..... :lol:

Member
Posts: 1211
Joined: Mon Mar 24, 2014 5:44 pm
Location: Aberdeenshire

Re: Making a better felt filter for the oil tank

Postby Mick D » Sun Feb 17, 2019 10:10 am

Hi

There are plenty of people advertising felt tube on 'tinternet, why not see if there's something suitable to adapt?

Maybe sandwich a tube between a couple of layers of mesh and turn a couple of nylon end caps.

I'd have a go myself but my bike doesn't use this filter.

Regards Mick

Member
User avatar
Posts: 179
Joined: Tue Nov 29, 2005 8:51 pm
Location: Herts UK

Re: Making a better felt filter for the oil tank

Postby Group Leader » Tue Feb 19, 2019 10:32 pm

Making the felt tube is the easy bit ....

Rolling the filter mesh without some decent rollers is rather more tricky, it's surprising just how stiff the mesh is!

Still, I think it's going to be "doable" eventually.

Soaking the felt in hot water helps ease it back on itself over the mesh. I wonder if it will shrink at all and tighten up when it dries out properly?

Mick's suggestion about ready made, seamless tube deserves some serious Googling at some point.

Anyway, a long way to go still with the mesh but I think the whole thing shows some promise.

Alan

Stumpy Filter.jpg
You do not have the required permissions to view the files attached to this post.
1953 AJS 16MS and a 1/3 scale Sopwith Triplane but that's another story ..... :lol:

PreviousNext

Return to Help

Who is online

Users browsing this forum: classic55 and 8 guests