mbrown
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Post by mbrown on May 28, 2020 22:03:45 GMT
A definite improvement!
Malcolm
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uuu
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Post by uuu on May 30, 2020 16:31:16 GMT
Just some tinkering today. The axleboxes needed a little taken off the flanges, to give a bit of end-float. As drawn there's no clearance at all, so the wheelsets could rise up and down as a whole, but one wheel on its own couldn't lift. My front axle had a tiny bit of play, but the rear had less than none. So with a bit of trimming, I've given them both about 25 thou - probably not enough, but better than none. Meanwhile, for David and Lily's benefit, here's my motion bracket castings. They've been cleaned up on the two side faces in the four-jaw, but otherwise they're as delivered. JessieMotionBrackets by Wilf, on Flickr Wilf
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Post by jon38r80 on May 30, 2020 19:41:28 GMT
It is no good, I cant help reading the title of this thread as Alias another Jessie having read it as that the first time
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Post by steamer5 on May 30, 2020 23:01:04 GMT
Jon, It could of been worse...… A BIG Jessie...….anybody whos a fan of Billy Connelly will understand!
Keep up the good work David & Wilf!
Off to my corner...…..again!
Cheers Kerrin
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dscott
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Post by dscott on May 30, 2020 23:46:59 GMT
Said of course in his wonderful accent!
I remember now 'splashing' out on water jet cut links instead of getting the motion brackets. Joke in there somewhere I just noticed!!! Yes it is often very satisfying to machine flat surfaces on the lathe and have more control and an extra 2 jaws holding onto it nicely.
Must upload my rear sandbox machining photo over on my pages!!!
David and Lily.
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uuu
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Post by uuu on Jun 2, 2020 9:53:19 GMT
Another question: Even though the designed trough on top of the axlebox is quite a sensible oiling arrangement, I thought I'd look at providing a pocket for a felt at the bottom. It's easy enough to mill out the opening, and fit a little cover-plate over it. But, since it would be quite difficult to get the oil from the trough at the top down into the felt pocket, I've got to arrange a way to do it. Here are my questions: - How big to make the felt pocket? The axle journal is 7/8" diameter and 1 1/8" long. I could have a 5mm round felt, right at the bottom - would this be big enough? (Thinking Myford Super 7, the big front bearing only has a very small round felt)
- Would the reservoir below the felt have to be bigger still, or would it be just fine the same size - I could fatten it to hold a bigger pool of oil.
- If I arranged to oil the felt from a drilling/cross-drilling in the axle, would the repeated passage of the hole across the surface of the felt tend to eat it, or would it glide harmlessly over - the oil supply hole could be small, say 1.5mm
Or tell me I'm mad and the as-drawn arrangement is fine. Wilf
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Post by Roger on Jun 2, 2020 10:57:55 GMT
Another question: Even though the designed trough on top of the axlebox is quite a sensible oiling arrangement, I thought I'd look at providing a pocket for a felt at the bottom. It's easy enough to mill out the opening, and fit a little cover-plate over it. But, since it would be quite difficult to get the oil from the trough at the top down into the felt pocket, I've got to arrange a way to do it. Here are my questions: - How big to make the felt pocket? The axle journal is 7/8" diameter and 1 1/8" long. I could have a 5mm round felt, right at the bottom - would this be big enough? (Thinking Myford Super 7, the big front bearing only has a very small round felt)
- Would the reservoir below the felt have to be bigger still, or would it be just fine the same size - I could fatten it to hold a bigger pool of oil.
- If I arranged to oil the felt from a drilling/cross-drilling in the axle, would the repeated passage of the hole across the surface of the felt tend to eat it, or would it glide harmlessly over - the oil supply hole could be small, say 1.5mm
Or tell me I'm mad and the as-drawn arrangement is fine. Wilf Hi Wilf, I've taken the sizes roughly from the LBSC drawing and that is 10 x 12 x 4mm deep. I originally looked at tiny drillways down to the pocket, and then concluded that any oil being fed into the bearing is probably going to saturate and eventually fill the pocket anyway. I guess the pocket can be pretty much as big as you like, the forces are negligeable in the downward direction. On full size, I don't think there's anything to stop the axle from moving right out of the bottom. To my way of thinking, a large reservoir on the top of the axlebox is also very useful. The drillway in the SPEEDY drawing isn't going to hold much oil, and that's the place where the forces are the greatest and you need it the most. Obviously oil in the bottom is going to get carried up from the felt too. Actually, I've added two drillways, one in front and one behind the centreline, just to make sure it's going to find its way in.
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Gary L
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Post by Gary L on Jun 2, 2020 23:37:45 GMT
Another question: Even though the designed trough on top of the axlebox is quite a sensible oiling arrangement, I thought I'd look at providing a pocket for a felt at the bottom. It's easy enough to mill out the opening, and fit a little cover-plate over it. But, since it would be quite difficult to get the oil from the trough at the top down into the felt pocket, I've got to arrange a way to do it. Here are my questions: - How big to make the felt pocket? The axle journal is 7/8" diameter and 1 1/8" long. I could have a 5mm round felt, right at the bottom - would this be big enough? (Thinking Myford Super 7, the big front bearing only has a very small round felt)
- Would the reservoir below the felt have to be bigger still, or would it be just fine the same size - I could fatten it to hold a bigger pool of oil.
- If I arranged to oil the felt from a drilling/cross-drilling in the axle, would the repeated passage of the hole across the surface of the felt tend to eat it, or would it glide harmlessly over - the oil supply hole could be small, say 1.5mm
Or tell me I'm mad and the as-drawn arrangement is fine. Wilf Hi Wilf, I've taken the sizes roughly from the LBSC drawing and that is 10 x 12 x 4mm deep. I originally looked at tiny drillways down to the pocket, and then concluded that any oil being fed into the bearing is probably going to saturate and eventually fill the pocket anyway. I guess the pocket can be pretty much as big as you like, the forces are negligeable in the downward direction. On full size, I don't think there's anything to stop the axle from moving right out of the bottom. To my way of thinking, a large reservoir on the top of the axlebox is also very useful. The drillway in the SPEEDY drawing isn't going to hold much oil, and that's the place where the forces are the greatest and you need it the most. Obviously oil in the bottom is going to get carried up from the felt too. Actually, I've added two drillways, one in front and one behind the centreline, just to make sure it's going to find its way in. I agree with Roger. In full-size the GWR (under Collett, if I remember correctly) redesign which eliminated hot boxes was to feed all the axlebox oil to the journal from a full-width felt pad below, in the keep. There was a long experimentation phase to find the best specification for the felt! The thinking was that the oil film is under highest pressure at the top of the bearing, which made it the very worst place to locate a feed hole. I don't know if the transverse width of the felt pocket was critical, but it had to extend across the whole length of the journal. Something similar was done with big ends too, and later exported to the Eastern/NE Region to fix the centre big ends on their Pacifics. The Bridget/Jessie arrangement is better than average but not perfect. The big trough full of oil on top of each axle box tends to collect all the ash dust and grit that's going (which is quite a lot on a steam loco) so heaven-knows-what can get carried down the oilway into the journal; or indeed block it, potentially. Some simple method of screening the oil feed is really needed, maybe a wick in the oilway or a thin felt filter in the bottom of the reservoir. No I haven't done it yet, but I keep telling myself I should... HTH Gary
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dscott
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Post by dscott on Jun 3, 2020 1:27:39 GMT
Four more things to bash out in the morning while everything is dismantled!
Yes 4 bits of thin angled brass that locate in the 2 spring bars and the central rod. The angle going down inside to the axle. It could go up inside the frames inside the Bar. There still being sufficient space if you lift her up and bung oil over the top of the wheels. Great thoughts. Thank you.
Anything else while she is undressed? I could use copper as I have loads of the thinner sheet.
David and Lily.
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Post by Roger on Jun 3, 2020 7:07:19 GMT
Hi Wilf, I've taken the sizes roughly from the LBSC drawing and that is 10 x 12 x 4mm deep. I originally looked at tiny drillways down to the pocket, and then concluded that any oil being fed into the bearing is probably going to saturate and eventually fill the pocket anyway. I guess the pocket can be pretty much as big as you like, the forces are negligeable in the downward direction. On full size, I don't think there's anything to stop the axle from moving right out of the bottom. To my way of thinking, a large reservoir on the top of the axlebox is also very useful. The drillway in the SPEEDY drawing isn't going to hold much oil, and that's the place where the forces are the greatest and you need it the most. Obviously oil in the bottom is going to get carried up from the felt too. Actually, I've added two drillways, one in front and one behind the centreline, just to make sure it's going to find its way in. I agree with Roger. In full-size the GWR (under Collett, if I remember correctly) redesign which eliminated hot boxes was to feed all the axlebox oil to the journal from a full-width felt pad below, in the keep. There was a long experimentation phase to find the best specification for the felt! The thinking was that the oil film is under highest pressure at the top of the bearing, which made it the very worst place to locate a feed hole. I don't know if the transverse width of the felt pocket was critical, but it had to extend across the whole length of the journal. Something similar was done with big ends too, and later exported to the Eastern/NE Region to fix the centre big ends on their Pacifics. The Bridget/Jessie arrangement is better than average but not perfect. The big trough full of oil on top of each axle box tends to collect all the ash dust and grit that's going (which is quite a lot on a steam loco) so heaven-knows-what can get carried down the oilway into the journal; or indeed block it, potentially. Some simple method of screening the oil feed is really needed, maybe a wick in the oilway or a thin felt filter in the bottom of the reservoir. No I haven't done it yet, but I keep telling myself I should... HTH Gary Hi Gary, "The big trough full of oil on top of each axle box tends to collect all the ash dust and grit that's going (which is quite a lot on a steam loco) so heaven-knows-what can get carried down the oilway into the journal; or indeed block it, potentially." Agreed, an open trough is a bad idea, hence the close fitting covers I've made for mine with a smaller hole for filling them. The traditional place for the feed hole is on the axle centre line, and that does seem to work, even though it's in the place of highest pressure. However, I thought one in front and one behind the centre line would guarantee that the one on the less loaded side would always feed a little. Any oil present will cause the axle to rise slightly onto the thin wedge of oil, and the axle will tend to move downwards and to the back while it's running and loaded. It would be interesting to know how long a bearing would last without a felt pad, where the only supply is that little hole in the top. I imagine that wouldn't last long at all, since it would likely spend most of its life running nearly dry. The felt pad still needs to be replenished, so in my opinion a wick or reservoir system is preferable to a one time filling of the pad from say a drillway in the end of the axle.
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uuu
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Post by uuu on Jun 3, 2020 11:21:05 GMT
Thank you all, for your suggestions. I think I may have some ideas to be sketched out: - A felt pad underneath, with a removable cover-plate for occasional servicing.
- A drilling top to bottom down one side.
- Either an internal drilling to connect the felt pocket with the vertical oil drilling, or a little canal along the bottom to do the same job, with a extension of the cover-plate.
- Either the vertical drilling is fed from the standard reservoir on top - but with a cover-plate - or a lidded oil cup sticking out of the back of the axlebox.
It might be fun getting oil in. The front axle is accessible under the boiler/saddle tank. The rear has the boiler above it and, in my loco, will be further hidden by coal bunkers. You could probably get to the standard trough through the spokes of the wheel (as noted by David and Lily). Wilf
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uuu
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Post by uuu on Jun 3, 2020 11:25:46 GMT
Meanwhile, I've been doing some mundane jobs: Making dowels for cylinder location, and getting 2BA bolts for the cylinder fixings to the right length. The right hand ones are longer than the left, due to an earlier error when drilling the fixing holes - I used a clearance drill instead of tapping size, so had to go deeper to recover.
Wilf
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Post by ettingtonliam on Jun 3, 2020 12:05:49 GMT
Rightly or wrongly, I opted for a felt pad in the bottom of the axlebox, and drilled axle ends with ball type oilers pressed in, and a cross drilling to let the oil out again. That way theres no anxt about 'where is the best place to put the oil drilling in the axlebox', no issues with ash getting in the oil boxes on top of the axleboxes and no problems with accessibility when oiling up. OK, so Locomotion in 1825 didn't have ball oil fittings in the axle ends, indeed its hard to tell how they did it, probably a pocket into which a lump of tallow was put, several times a day.
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Post by simplyloco on Jun 3, 2020 12:05:52 GMT
Meanwhile, I've been doing some mundane jobs: Making dowels for cylinder location, and getting 2BA bolts for the cylinder fixings to the right length. The right hand ones are longer than the left, due to an earlier error when drilling the fixing holes - I used a clearance drill instead of tapping size, so had to go deeper to recover.Wilf You mean that I am not alone? John
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uuu
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Post by uuu on Jun 3, 2020 12:50:07 GMT
Rightly or wrongly, I opted for a felt pad in the bottom of the axlebox, and drilled axle ends with ball type oilers pressed in, and a cross drilling to let the oil out again. That way theres no anxt about 'where is the best place to put the oil drilling in the axlebox', no issues with ash getting in the oil boxes on top of the axleboxes and no problems with accessibility when oiling up. OK, so Locomotion in 1825 didn't have ball oil fittings in the axle ends, indeed its hard to tell how they did it, probably a pocket into which a lump of tallow was put, several times a day. So you've no issues with the cross-drilling "eating" the felt as it passes over? Wilf
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uuu
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Post by uuu on Jun 3, 2020 12:58:05 GMT
Just so people can see what we're on about - here's a bit of the relevant drawing: JessieDrawing by Wilf, on Flickr I think if I put a cover over the top of the axlebox (which has an oil trough in it) then I could have an oil nipple pointing outwards, to be accessed between the spokes. Jacking the loco up will provide some extra clearance when oiling, or I could take a small bite out of the frame. I know we keep banging on about Ken's excellent drawings - here's an example. It's an arrangement drawing, to show how everything fits together - chassis side and top view. You can see the clearance between the axle and the ashpan - the way the blowdown has an arrow from a label, as does the grate. And the pipe to the whistle is numbered (No. 18) and cross-refers to a complete list of pipes (on the final sheet) with their undeveloped lengths (14"), nipples fixings etc (U3 and C3 this end, another U3 and C3 on the other end) and that this pipe appears on drawings 5 and 14. Wilf
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Post by ettingtonliam on Jun 3, 2020 13:42:40 GMT
Rightly or wrongly, I opted for a felt pad in the bottom of the axlebox, and drilled axle ends with ball type oilers pressed in, and a cross drilling to let the oil out again. That way theres no anxt about 'where is the best place to put the oil drilling in the axlebox', no issues with ash getting in the oil boxes on top of the axleboxes and no problems with accessibility when oiling up. OK, so Locomotion in 1825 didn't have ball oil fittings in the axle ends, indeed its hard to tell how they did it, probably a pocket into which a lump of tallow was put, several times a day. So you've no issues with the cross-drilling "eating" the felt as it passes over? Wilf None at all. I just lightly countersink the end of the drilling, and polish the journal.
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Post by Roger on Jun 3, 2020 13:45:54 GMT
If it's like mine, I can get a small nozzle between the spokes to fill the reservoirs
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Post by steamer5 on Jun 3, 2020 14:37:28 GMT
Hi Wilf, On my loco, it came with an open trough, like you have. I had the same concerns re the ash etc, so my solution was to put a piece of felt, found some that wasn't a tight weave (if that's the right term for felt!) cut larger than the trough, this was covered with shim stock with a hole in it so that I can pump oil thru the felt into the trough. Works well, very occasionally I take the cover off & clean the felt. Keep up the great work.
Cheers Kerrin
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Gary L
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Post by Gary L on Jun 4, 2020 0:51:04 GMT
I agree with Roger. In full-size the GWR (under Collett, if I remember correctly) redesign which eliminated hot boxes was to feed all the axlebox oil to the journal from a full-width felt pad below, in the keep. There was a long experimentation phase to find the best specification for the felt! The thinking was that the oil film is under highest pressure at the top of the bearing, which made it the very worst place to locate a feed hole. I don't know if the transverse width of the felt pocket was critical, but it had to extend across the whole length of the journal. Something similar was done with big ends too, and later exported to the Eastern/NE Region to fix the centre big ends on their Pacifics. The Bridget/Jessie arrangement is better than average but not perfect. The big trough full of oil on top of each axle box tends to collect all the ash dust and grit that's going (which is quite a lot on a steam loco) so heaven-knows-what can get carried down the oilway into the journal; or indeed block it, potentially. Some simple method of screening the oil feed is really needed, maybe a wick in the oilway or a thin felt filter in the bottom of the reservoir. No I haven't done it yet, but I keep telling myself I should... HTH Gary Hi Gary, "The big trough full of oil on top of each axle box tends to collect all the ash dust and grit that's going (which is quite a lot on a steam loco) so heaven-knows-what can get carried down the oilway into the journal; or indeed block it, potentially." Agreed, an open trough is a bad idea, hence the close fitting covers I've made for mine with a smaller hole for filling them. The traditional place for the feed hole is on the axle centre line, and that does seem to work, even though it's in the place of highest pressure. However, I thought one in front and one behind the centre line would guarantee that the one on the less loaded side would always feed a little. Any oil present will cause the axle to rise slightly onto the thin wedge of oil, and the axle will tend to move downwards and to the back while it's running and loaded. It would be interesting to know how long a bearing would last without a felt pad, where the only supply is that little hole in the top. I imagine that wouldn't last long at all, since it would likely spend most of its life running nearly dry. The felt pad still needs to be replenished, so in my opinion a wick or reservoir system is preferable to a one time filling of the pad from say a drillway in the end of the axle. Hi Roger (and Wilf) Yes, in full size the felt pad was both a wick and a spreader, and had its feet in an oil reservoir. I must look up the story again, but I seem to recall that the plug for the reservoir had to be specially designed to prevent dyed-in-the-wool old timer enginemen from inserting worsted trimmings into it! I don't think the principle would transfer all that well to scaled models though. It is difficult to make 'trimmings' work in miniature, and I suspect a felt pad might be an unnecessary complication. Relative to full size, our bearings don't run hot, because liquids don't scale, and our bearings can retain a massively thick and sticky oil film in comparison. I think the average model loco bearing gets a squirt of oil at the start of running, which lasts until the next time the driver thinks of giving it another, which could be an hour later, or more. I don't think running dry is a particular issue, especially with modern extra-sticky oil (I use Chainsaw oil myself) It goes without saying that the main problem is getting the oil into the bearing in the first place, which isn't always as easy as it sounds. Logically Wilf's suggestion of feeding the oil to one side rather than the top of the bearing makes a lot of sense, as would oil grooves to help spread it. By contrast an oil groove at the top of a bearing is more likely to scrape the oil off than to distribute it, I would think. If only I had been so very clever when I finished off the axle boxes on Paddington... Gary
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