Constructing the Josslin Hudson
Moderator: Harold_V
Re: Constructing the Josslin Hudson
Sometimes, you gotta do what you gotta do! Been there done that many times.
Re: Constructing the Josslin Hudson
Proceeding with "the fix". Most of the work involved disassembly and then re- assembly of all of the parts.
Nothing special here, just some careful work.
Once I removed an axlebox, the axlebox was setup in the vise of the mill on parallels as shown in the first photo. Small step plugs were used to keep the parts aligned in the previously drilled holes and a longer aligning plug held in a collet was used to "pick up" the exact location for the 82 degree countersink to follow.
Then carefully/lightly countersink the hole until the head of the flat head screw sits just below the surface of the axlebox ear. The slotted head screws are only temporary as that is all I had in stock. Awaiting the arrival of the cap head screws before final re-assembly.
Nothing special here, just some careful work.
Once I removed an axlebox, the axlebox was setup in the vise of the mill on parallels as shown in the first photo. Small step plugs were used to keep the parts aligned in the previously drilled holes and a longer aligning plug held in a collet was used to "pick up" the exact location for the 82 degree countersink to follow.
Then carefully/lightly countersink the hole until the head of the flat head screw sits just below the surface of the axlebox ear. The slotted head screws are only temporary as that is all I had in stock. Awaiting the arrival of the cap head screws before final re-assembly.
Re: Constructing the Josslin Hudson
More pain!!!
After the first trial fitting of the side rods, they would partially rotate and then jam solid. After removing the RH rod assembly, the LH rod assembly would rotate perfectly on the drivers but as soon as the RH rod assembly was added, the side rods would jam solid again.
It soon became apparent why. See the first photo. The RH rod assembly was locking up on the square axle key stick out and as well, to a lesser degree, on the axle stick out itself.
This had to be remedied by shaving away both the axle key and the end of the axle. But how to do this and not spoil the work which had already been done?
The easiest solution would have been to turn the driver assembly between centres in the lathe but this was not possible as there was nothing to hold on to. After many frustrating non productive partial setups, the setup seen in the second photo, although a bit dodgy, did the job. One could not use a chuck, faceplate or drive plate because either they were too thick to locate the headstock centre in the axle centre or it proved impossible to locate more than one fastener in a driver casting and not have it bind. Also, one had to have the tailstock end of the driver assembly fully accessible due to the interference of the rod pin. Until one has faced a situation like this, it appears to be a rather simple fix but it isn't.
I finally found an old unused small lathe backplate which I was able to employ as an improvised driver and managed to thread two bolts through the BoxPok wheel openings at roughly 180 degrees apart (but the bolts ended up being quite canted)( actually all of the the fasteners should go straight through ideally but the Boxpok wheel openings did not allow this) which reduced the binding problem to a manageable level.
Use a very sharp cutting tool and take very light shaving cuts. Check often the canted bolts just keeping them snug at all times because if they let go, the entire assembly can move endwise and disaster will ensue.
As some of the other drivers exhibit the above problems to a much lesser degree, they need to be dealt with in a similar manner but the end result looks good.
After the first trial fitting of the side rods, they would partially rotate and then jam solid. After removing the RH rod assembly, the LH rod assembly would rotate perfectly on the drivers but as soon as the RH rod assembly was added, the side rods would jam solid again.
It soon became apparent why. See the first photo. The RH rod assembly was locking up on the square axle key stick out and as well, to a lesser degree, on the axle stick out itself.
This had to be remedied by shaving away both the axle key and the end of the axle. But how to do this and not spoil the work which had already been done?
The easiest solution would have been to turn the driver assembly between centres in the lathe but this was not possible as there was nothing to hold on to. After many frustrating non productive partial setups, the setup seen in the second photo, although a bit dodgy, did the job. One could not use a chuck, faceplate or drive plate because either they were too thick to locate the headstock centre in the axle centre or it proved impossible to locate more than one fastener in a driver casting and not have it bind. Also, one had to have the tailstock end of the driver assembly fully accessible due to the interference of the rod pin. Until one has faced a situation like this, it appears to be a rather simple fix but it isn't.
I finally found an old unused small lathe backplate which I was able to employ as an improvised driver and managed to thread two bolts through the BoxPok wheel openings at roughly 180 degrees apart (but the bolts ended up being quite canted)( actually all of the the fasteners should go straight through ideally but the Boxpok wheel openings did not allow this) which reduced the binding problem to a manageable level.
Use a very sharp cutting tool and take very light shaving cuts. Check often the canted bolts just keeping them snug at all times because if they let go, the entire assembly can move endwise and disaster will ensue.
As some of the other drivers exhibit the above problems to a much lesser degree, they need to be dealt with in a similar manner but the end result looks good.
- Attachments
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- 921 The Front Driver Square Axle Key and Axle Stickout.jpg (902.81 KiB) Viewed 3233 times
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- 922 The Setup to Shave Down the Key and Axle Stickout.jpg (910.9 KiB) Viewed 3233 times
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- 923 After the Shaving Operation.jpg (979.06 KiB) Viewed 3233 times
Re: Constructing the Josslin Hudson
Yep, 85% of machine work is in the figuring out of and doing the setup! lol
- Dick_Morris
- Posts: 2851
- Joined: Sat Jan 04, 2003 2:09 pm
- Location: Anchorage, AK
Re: Constructing the Josslin Hudson
An alternative to the steady rest would be a half dead center. Here is a short video showing one in use. https://www.youtube.com/watch?v=B3-WmES ... tisanMakes
Re: Constructing the Josslin Hudson
Hi Dick,
This was one of my first thoughts also and I do have a half centre but it turned out the existing axle centre holes were too small to be able to use a half centre. I was not going to try and recut the centre holes larger and risk throwing everything out of truth as with the existing wheel set put between centres in the lathe, everything ran true without any wobble or eccentricity so I knew everything was truly square and concentric with the existing centres.
This was one of my first thoughts also and I do have a half centre but it turned out the existing axle centre holes were too small to be able to use a half centre. I was not going to try and recut the centre holes larger and risk throwing everything out of truth as with the existing wheel set put between centres in the lathe, everything ran true without any wobble or eccentricity so I knew everything was truly square and concentric with the existing centres.
Re: Constructing the Josslin Hudson
After finally getting the side rods to turn freely without binding, it was time to finish all of the suspension bits and pieces.
Years ago, I made a lot of the suspension parts and leaf springs (as described at the beginning of this thread) but there is still one last spring hanger set to make. This needs to be a fabrication as there were no castings ever made for these hangers.
The first sub part to be made is the hanger upper piece and this needs to be a flat tab silver soldered to the bottom round hollow. Since I stick with the devil I know, these two pieces have been made from hot rolled structural steel as I know that hot rolled steel will form a true structural joint when silver soldered.
Years ago, I made a lot of the suspension parts and leaf springs (as described at the beginning of this thread) but there is still one last spring hanger set to make. This needs to be a fabrication as there were no castings ever made for these hangers.
The first sub part to be made is the hanger upper piece and this needs to be a flat tab silver soldered to the bottom round hollow. Since I stick with the devil I know, these two pieces have been made from hot rolled structural steel as I know that hot rolled steel will form a true structural joint when silver soldered.
- Attachments
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- 924 The Previously Made Suspension Parts.jpg (206.5 KiB) Viewed 2830 times
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- 925 Suspension Hangers Remaining to Fabricate.jpg (125.45 KiB) Viewed 2830 times
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- 926 First Fabrication Steps.jpg (132.24 KiB) Viewed 2830 times
Re: Constructing the Josslin Hudson
Moving ahead.
Since a lot of this fabrication work is routine (keeping everything square, parallel and on size), I will only describe some of the most interesting procedures.
If you ever need to employ the following tricky layout setup, here is how to do it accurately. I think the photos are self explanatory.
When scribing, just put your fingers on the top surface of the base of the square and lightly press down on the square and the tab to keep everything square and in place.
Since a lot of this fabrication work is routine (keeping everything square, parallel and on size), I will only describe some of the most interesting procedures.
If you ever need to employ the following tricky layout setup, here is how to do it accurately. I think the photos are self explanatory.
When scribing, just put your fingers on the top surface of the base of the square and lightly press down on the square and the tab to keep everything square and in place.
- Attachments
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- 927 A Tricky Layout Setup.jpg (96.14 KiB) Viewed 2800 times
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- 928 A Tricky Layout Setup.jpg (94.57 KiB) Viewed 2800 times
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- 929 A Tricky Layout Setup.jpg (109.2 KiB) Viewed 2800 times
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- 932 After Scribing.jpg (135.9 KiB) Viewed 2800 times
Re: Constructing the Josslin Hudson
Moving on.
To centre and mill miniature slots the quick and dirty way by purely manual methods. This time I had to mill a 1/8" wide by 5/32" long centred slot in all of the tab pieces which had been previously scribed. The tab pieces themselves are only 9/32" wide by 3/32" thick as shown on the Josslin print.
For those of you with CNC or digital you can just ignore all of this.
To centre something on a flat bar (the 9/32" wide tab in this case),
You can machine up a 9/32" wide waste piece first, scribe a centreline on it with your height gauge, put it in the vise and with the smallest centre drill held in a collet, pick up the scribed centre line as best you can (I use good lighting and an eye loupe), then drill and ream a 1/8" through hole. Take the piece out of the vise and measure with your vernier calipers each side wall width at the hole. If they are not the same, move the crosslide over 1/2 of the difference and repeat. Using this method I can get any flat part centred well within 0.001" after two iterations. It is really stupid but it works.
More advise.
Firstly, with these short miniature pieces, don't try and mill the slots at the end of the vise jaws, do it in the centre of the jaws as the parts have to be held very securely and evenly. The part was set up on an adjustable parallel upon which a cut out centre relieved spacer was placed and the tab blank was then placed over the relieved spacer where the slot was to be machined.
I always drill a pilot through hole first followed by the end mill. This allows the end mill chip relief as these small cutters can jam and break very easily.
To centre and mill miniature slots the quick and dirty way by purely manual methods. This time I had to mill a 1/8" wide by 5/32" long centred slot in all of the tab pieces which had been previously scribed. The tab pieces themselves are only 9/32" wide by 3/32" thick as shown on the Josslin print.
For those of you with CNC or digital you can just ignore all of this.
To centre something on a flat bar (the 9/32" wide tab in this case),
You can machine up a 9/32" wide waste piece first, scribe a centreline on it with your height gauge, put it in the vise and with the smallest centre drill held in a collet, pick up the scribed centre line as best you can (I use good lighting and an eye loupe), then drill and ream a 1/8" through hole. Take the piece out of the vise and measure with your vernier calipers each side wall width at the hole. If they are not the same, move the crosslide over 1/2 of the difference and repeat. Using this method I can get any flat part centred well within 0.001" after two iterations. It is really stupid but it works.
More advise.
Firstly, with these short miniature pieces, don't try and mill the slots at the end of the vise jaws, do it in the centre of the jaws as the parts have to be held very securely and evenly. The part was set up on an adjustable parallel upon which a cut out centre relieved spacer was placed and the tab blank was then placed over the relieved spacer where the slot was to be machined.
I always drill a pilot through hole first followed by the end mill. This allows the end mill chip relief as these small cutters can jam and break very easily.
- Attachments
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- 933 Predrilling Prior to Slotting.jpg (124.46 KiB) Viewed 2757 times
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- 934 Slotting Operation.jpg (153.57 KiB) Viewed 2757 times
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- 935 After Slotting.jpg (143.35 KiB) Viewed 2757 times
Re: Constructing the Josslin Hudson
Well, here it is. Probably only I could come up with something this complicated.
My Rube Goldberg fixture for aligning, squaring and holding the upper bracket parts together for silver soldering. It was made from old workshop bits and pieces and a bad, half made, locomotive part that never made it.
Not only does this fixture have to achieve the above, one also has to have complete access to and be able to clearly see everything (while silver soldering).
My Rube Goldberg fixture for aligning, squaring and holding the upper bracket parts together for silver soldering. It was made from old workshop bits and pieces and a bad, half made, locomotive part that never made it.
Not only does this fixture have to achieve the above, one also has to have complete access to and be able to clearly see everything (while silver soldering).
- Attachments
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- 936 The Silver Soldering Parts Holding Fixture.jpg (205.4 KiB) Viewed 2706 times
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- 937 Aligning and Squaring the Parts Before Silver Soldering.jpg (184.59 KiB) Viewed 2701 times
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- 938 Closeup of the Parts to be Silver Soldered.jpg (135.66 KiB) Viewed 2701 times
Re: Constructing the Josslin Hudson
Ya gotta do what ya gotta do lol
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- Posts: 1572
- Joined: Thu Apr 26, 2012 10:15 am
- Location: Tennessee, USA
Re: Constructing the Josslin Hudson
Hope it all comes out square for you.