Parkinson's law "Work expands to fill the time available."
Decided the three Josslin lead trucks made to date need brakes so now there are 12 brake lugs in various stages of construction.
Constructing the Josslin Hudson
Moderator: Harold_V
Re: A Peek At The Josslin Hudson Lead Truck
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Re: A Peek At The Josslin Hudson Lead Truck
Carving part of a brake lug's final contour.
The setup's are becoming more and more interesting as the amount of metal one can hold on to decreases.
For this operation am using a new 4 flute coated carbide ball end mill as that is what I have. Am running the cutter as fast as the mill will turn in the third pulley setting (which is still too slow compared to what is done commercially) but it is doing a beautiful job - just take very light cuts and lean on the vise handle to ensure nothing moves.
Again, a job to do when one is in the right mood as radii have to be blended into a line.
The setup's are becoming more and more interesting as the amount of metal one can hold on to decreases.
For this operation am using a new 4 flute coated carbide ball end mill as that is what I have. Am running the cutter as fast as the mill will turn in the third pulley setting (which is still too slow compared to what is done commercially) but it is doing a beautiful job - just take very light cuts and lean on the vise handle to ensure nothing moves.
Again, a job to do when one is in the right mood as radii have to be blended into a line.
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Re: A Peek At The Josslin Hudson Lead Truck
A little further on. All 12 brake lugs are now approaching final contouring.
Doesn't look very different than previously (photo 483) but have added another week of machining. It is slow work and I take it on in 2-3 hour sessions. After that impatience or lack of concentration kicks in.
Doesn't look very different than previously (photo 483) but have added another week of machining. It is slow work and I take it on in 2-3 hour sessions. After that impatience or lack of concentration kicks in.
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Re: A Peek At The Josslin Hudson Lead Truck
Another week of machining and a bakers dozen lead truck brake lugs nearing completion. Just more slow and careful milling. And there were a couple of scrapped pieces too.
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Re: A Peek At The Josslin Hudson Lead Truck
A LH lead truck brake lug more or less finished.
The remaining work was to rough saw the other side of the lug's contour and then finish the profile by hand filing in a bench vise.
Things did not go as planned. Originally intended to profile mill the remaining side as with the first side. Thought I had come up with an ingenious and very rigid holding setup but the end mill thought otherwise. Snapped the end mill off at the root (a new one taking very light cuts) and left horrible gouges in the work.
So after spending hours of hand work repairing the damage only have 11 more to do (by hand).
The remaining work was to rough saw the other side of the lug's contour and then finish the profile by hand filing in a bench vise.
Things did not go as planned. Originally intended to profile mill the remaining side as with the first side. Thought I had come up with an ingenious and very rigid holding setup but the end mill thought otherwise. Snapped the end mill off at the root (a new one taking very light cuts) and left horrible gouges in the work.
So after spending hours of hand work repairing the damage only have 11 more to do (by hand).
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Re: A Peek At The Josslin Hudson Lead Truck
Finished a set of 4 brake lugs by careful belt sanding and hand filing; then temporarily set them up on the partially completed side frames. The spacer pieces still have to be shortened for the lugs inner cutouts to clear the leaf spring equalizer pieces and the equalizer spring hanger pins.
It was good that I had several completed lead trucks so as to be able to check clearances. It turns out there is very little room to add brakes and still have the lead truck move as intended.
As noted previously, a model lead truck has to be able to rotate, translate and rock more than the prototype lead truck so more clearance is required on the model. I guess that is why you don't see lead truck brakes on a lot of working live steam models. Even on the Yankee Shop NYC Hudson which has been run here for 30 years (where lead truck brakes are part of the design), the truck brakes have been removed.
I moved the brake hanger slots 1/32" further away on each brake lug (total 1/16" for both sides) from the truck side frames after seeing what happens after 30 years of use. It is another story but it is very instructive to note what happens to a model after many owners and 30 years of use and abuse and to closely examine a model that has worn in by wearing out.
The full size NYC Hudson has a complicated lead truck brake linkage system which further complicates and restricts things. I still can't figure out how the secondary lead truck brake cylinder could be added. I know where it goes but there is absolutely no room for it on the model.
Anyway, back to more practical things. First to finish the side frames. Then I have to decide whether to "bolt on" the truck brake lug assembly from the inside of the frames with miniature recessed flat head cap screws or to just silver solder the entire mess to the side frame and risk distortion on the already completed frame axlebox openings. In retrospect, it may have been better to have left the frame axlebox openings rough machined only for finishing later. But then it is much more difficult to hold, machine and keep square an entire frame casting or side frame which has integral brake lugs.
So, no matter what one does, there will be endless issues to resolve.
It was good that I had several completed lead trucks so as to be able to check clearances. It turns out there is very little room to add brakes and still have the lead truck move as intended.
As noted previously, a model lead truck has to be able to rotate, translate and rock more than the prototype lead truck so more clearance is required on the model. I guess that is why you don't see lead truck brakes on a lot of working live steam models. Even on the Yankee Shop NYC Hudson which has been run here for 30 years (where lead truck brakes are part of the design), the truck brakes have been removed.
I moved the brake hanger slots 1/32" further away on each brake lug (total 1/16" for both sides) from the truck side frames after seeing what happens after 30 years of use. It is another story but it is very instructive to note what happens to a model after many owners and 30 years of use and abuse and to closely examine a model that has worn in by wearing out.
The full size NYC Hudson has a complicated lead truck brake linkage system which further complicates and restricts things. I still can't figure out how the secondary lead truck brake cylinder could be added. I know where it goes but there is absolutely no room for it on the model.
Anyway, back to more practical things. First to finish the side frames. Then I have to decide whether to "bolt on" the truck brake lug assembly from the inside of the frames with miniature recessed flat head cap screws or to just silver solder the entire mess to the side frame and risk distortion on the already completed frame axlebox openings. In retrospect, it may have been better to have left the frame axlebox openings rough machined only for finishing later. But then it is much more difficult to hold, machine and keep square an entire frame casting or side frame which has integral brake lugs.
So, no matter what one does, there will be endless issues to resolve.
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Re: A Peek At The Josslin Hudson Lead Truck
More drum sanding of the lead truck side frames. The drill press is being run at the highest pulley speed which is 3000 rpm in my case. The aligning plugs in the frame openings are used as finger holds which guide the contouring (all hand work) to the paper layout line. Light sanding pressure and lots of patience are essential as one does not want to have a lot of side pressure on the drill press spindle bearings. Drum sanding like belt sanding makes quite a mess.
As a break from the monotony of construction, the third photo was taken last weekend when TSME had their extended intermission at the Richmond Hill Live Steamers. The locomotive is a Brian Gittins Pennsy E-6 in 7.25" gauge (think Modeltec and Saturated Steam). Not many of these locomotives were ever built. It will run all day with no problems whatsoever but does it consume coal compared to 3/4" scale locomotives.
As a break from the monotony of construction, the third photo was taken last weekend when TSME had their extended intermission at the Richmond Hill Live Steamers. The locomotive is a Brian Gittins Pennsy E-6 in 7.25" gauge (think Modeltec and Saturated Steam). Not many of these locomotives were ever built. It will run all day with no problems whatsoever but does it consume coal compared to 3/4" scale locomotives.
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Re: A Peek At The Josslin Hudson Lead Truck
Next operation is to fit the pedestal tie bars to the side frames to close the side frame axlebox openings.
The procedure to do this is exactly the same as previously described for the fitting of the pedestal ties to the main frame axlebox openings except here there are two openings per pedestal tie to make things more interesting.
The real problem is to control/minimize any warpage and slight bending in these long slender pieces from the pressure of any end milling operations. One should use a vise whose jaws are longer than the rough tie bar in length and also support the rough tie bar on a spacer or parallel which also is longer than the tie bar when machining the pedestal jaw slots in the tie bars. I didn't so the slots in the tie bars ended up slightly different depths after machining.
It is a bit more difficult than it looks to have all four slots in the pedestal tie bar align as a nice push fit which is what they are. Care, experience and one's mood will all affect the outcome.
The procedure to do this is exactly the same as previously described for the fitting of the pedestal ties to the main frame axlebox openings except here there are two openings per pedestal tie to make things more interesting.
The real problem is to control/minimize any warpage and slight bending in these long slender pieces from the pressure of any end milling operations. One should use a vise whose jaws are longer than the rough tie bar in length and also support the rough tie bar on a spacer or parallel which also is longer than the tie bar when machining the pedestal jaw slots in the tie bars. I didn't so the slots in the tie bars ended up slightly different depths after machining.
It is a bit more difficult than it looks to have all four slots in the pedestal tie bar align as a nice push fit which is what they are. Care, experience and one's mood will all affect the outcome.
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JBodenmann
- Posts: 3865
- Joined: Sun Oct 26, 2003 1:37 pm
- Location: Tehachapi, California
Re: A Peek At The Josslin Hudson Lead Truck
Hi Cardo
The lead truck is really looking good. It's a shame it will be mostly hidden down under the cylinders. I also use drum sanders, both large and small 1/4" up to 4". Fine metal finishing is important and will make a good model into an excellent one. Keep up the postings I enjoy seeing your work.
Jack
The lead truck is really looking good. It's a shame it will be mostly hidden down under the cylinders. I also use drum sanders, both large and small 1/4" up to 4". Fine metal finishing is important and will make a good model into an excellent one. Keep up the postings I enjoy seeing your work.
Jack
Re: A Peek At The Josslin Hudson Lead Truck
A little further on.
To attach the tie bars after slotting one needs 8 studs and nuts and to drill and tap the side frame pedestal jaws a total of 8 times.
Making studs (which I used here instead of bolts) is an exercise in itself. I don't plan on going into this unless someone wants the details. For such simple pieces, there are a few tricks involved to have them come out right.
Another round of seemingly endless dog work but one has to be careful with the laying out/drilling/tapping as the eye can pick up the slightest error.
Jack, you must have some divine assistance to do what you do in the time you do it.
To attach the tie bars after slotting one needs 8 studs and nuts and to drill and tap the side frame pedestal jaws a total of 8 times.
Making studs (which I used here instead of bolts) is an exercise in itself. I don't plan on going into this unless someone wants the details. For such simple pieces, there are a few tricks involved to have them come out right.
Another round of seemingly endless dog work but one has to be careful with the laying out/drilling/tapping as the eye can pick up the slightest error.
Jack, you must have some divine assistance to do what you do in the time you do it.
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Re: A Peek At The Josslin Hudson Lead Truck
Final contouring of the side frame tie bars. More milling, belt and drum sanding.
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Re: A Peek At The Josslin Hudson Lead Truck
The last two operations on the side frame assemblies are to machine the side frames to their final thickness and then to stamp or etch assembly marks on each side frame and its corresponding tie bar.
Milling the side frames would have been much quicker and cleaner but holding them on a magnetic chuck was much easier but very much slower and the grinding grit covers everything.
Just some experience with stamping.
When stamping thin delicate parts like the tie bars, they can distort very easily so I feel etching is a better solution in these cases or have them very well supported or clamped but as I don't yet have an etching pen.... Also, before stamping or etching, make certain everything is aligned the way you want it to be for final assembly as it is easy to have items reversed or stamped or etched on the outside face when you really meant to have them stamped on the inside face or vice versa.
For axleboxes, frame axlebox openings, tie bars and related hardware I usually mark them as 1R(ight), 1L(eft), 2R, 2L, 3R, 3L, etc. but make certain that you are happy that 1R and 1L is what you want as "front".
Milling the side frames would have been much quicker and cleaner but holding them on a magnetic chuck was much easier but very much slower and the grinding grit covers everything.
Just some experience with stamping.
When stamping thin delicate parts like the tie bars, they can distort very easily so I feel etching is a better solution in these cases or have them very well supported or clamped but as I don't yet have an etching pen.... Also, before stamping or etching, make certain everything is aligned the way you want it to be for final assembly as it is easy to have items reversed or stamped or etched on the outside face when you really meant to have them stamped on the inside face or vice versa.
For axleboxes, frame axlebox openings, tie bars and related hardware I usually mark them as 1R(ight), 1L(eft), 2R, 2L, 3R, 3L, etc. but make certain that you are happy that 1R and 1L is what you want as "front".
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