Here is a list of all the postings IanH has made in our forums. Click on a thread name to jump to the thread.
|Thread: EN40 nitrided repair|
Lots of good stuff in these replies.
I think the best solution may be to scrap the faulty levers and go back around the casting loop. If we make new waxes with the old tooling, we can correct the waxes by hand before casting in EN40, then machine and nitride as usual.
Thanks for all those thoughts, I think finding the specialist welder and agreeing the plan with him sounds like an essential first step.
We have some cam levers lost wax cast in EN40 then machined and subsequently selectively (at least according to the drawing) nitrided. The tappet pad it turns out is in the wrong position so we could do with building this up with weld and the re-profiling and re-hardening.
Does anyone have any words of wisdom on how to go about this?
|Thread: Lathe - dead centre wont reach the workpiece|
John Stevenson’s post briefly mentions something that I have observed having been through the exercise of replacing my Student with an imported machine.
I think there was a huge amount of development based on testing and real life operating experience built into the design of all those old British (and probably EU and US) machines. The imported machines seemingly have all the right bits in all the right places, but they often do not seem to have spotted or understood the subtleties of the designs they are copying that make machines really work.
I am not sure either that the current supply chain is going to result in these subtleties being identified and incorporated in imported machines over time.
having said that, model engineering I think is largely about doing unlikely things with inappropriate equipment and this just becomes one additional factor to challenge your ingenuity. Where there is a will, the model engineer will find a way.
Edited By IanH on 10/08/2019 08:28:49
Edited By IanH on 10/08/2019 08:29:48
|Thread: What Did You Do Today 2019|
I used my bargain ALDI endoscope to keep an eye on drilling the seal bypass ports in a brake master cylinder I have been making. I knew it would come in handy one day!
|Thread: Myford 254s tooling|
Mine has a QCTP that I am pretty sure came with the machine, new from Myford. The slot in the standard holders measures 0.555” or thereabouts.
I use tipped tools almost exclusively, and for use on my 254, I have machined a number of them down to fit the QCTP.
|Thread: Rounded Torx Screw Removal|
Look up the thread “saving a tool holder” on here to see another way of doing it.
|Thread: Belt sander recommendations|
I have a device currently marketed by Multitool Products which is a bolt-on to a conventional bench grinder. I have had this for donkey’s years and it continues to give excellent service. Have a look at Multitoolproducts.com
|Thread: What Did You Do Today 2019|
Set about modifying a Jag rev counter for the Morgan. I removed the defunct clock from the bottom of the old instrument and made a “medallion” with the JAP logo on the CNC machine to go in its place.
|Thread: D1-3 spindle nose adaptor|
This is then used first of all to machine the eccentric cam, then whilst still in the jog, the cam is trasferred to the milling machine for all the subsequent operations....the cut out to clear the cam lock pin, the 45 degree face and the hole for the stop bolt detent. Note that getting these features in the right orientation to each other is important so I marked up the jig to show this and also made sure that the hexagon was aligned consistently with the other features. I aligned the hexagon anticipating leaving off the detent feature and needed a way to indicate that the cam was disengaged.
Here is a cam ready for de-burring.
Once de-burred the chucking piece can be machined off and everything fitted together for testing. I added a centre pop on the end of each cams hexagon indicating the position when the cam was fully released.
The first picture in the previous post shows the finished item ready to go - maybe I will add the detent, but for now I have to get on with some other things so that will wait for another day.
Thanks to Murray for kicking this all off - it is a great idea.
Having just bought a rotary table with a controller attached, the idea of being able to move chucks direct from the lather to the rotary table appealed. I read this post and exchanged notes with Murray and set to. My design is based on the standard but differs from Murray's in that my rotary table only has three slots which makes things easier, I also put hexagon heads on the cams but stayed closer to the standard stop bolt orientation to keep the height of the adaptor to a minimum. I did not bother making the spring loaded stop bolt arrangement but could add this later I suppose.
The standard is not so easy to use as it gives design detail for the full range of cam lock spindles but you can puzzle it out.
I came across another post questioning the design of the cams themselves so I thought it might be useful if I shared my understanding and the method of making them.
The first question was about the cam profile and the angle "v" on the standard. I am on the same page as Murray here and believe that the cam profile is in fact a circle - with a bit of geometry you can work out that for the D1-3 cam the diameter of the cam portion is 0.677" and it is eccentric to the body of the cam by 0.031". The angle "v" on the drawing essentially shows that the required cam action occurs over this angle, the dimensions "d" and "e" tell you the extent of the cam action. having made them to this scheme I can confirm that it all works fine.
When it comes to making them I started with three blanks featuring a chucking piece on the inboard end of each blank. The outboard end is extended versus the standard to take the hexagon rather then the square hole as specified.
I have a smallish 3 jaw chuck with a large hexagon shaped lump on the back in place of a back plate - I use this in the milling machine to put the hexagons on.
Next I made up a little jig block that in based on a square but has a hole for the chucking piece through it offset by the required 0.031" eccentricity. It also has a register at the same eccentricity to allow it to be held in the 3 jaw to turn the eccentric cam. I also added flats on the block at 45 degrees to facilitate the later machining of the 45 degree feature.
Let me just add a photo of that....
|Thread: Fork and blade conrods|
Thanks for your thoughts.
I am looking specifically at pre war JAP engines (and Harley Davidson practice up to the current day) where a built up crank avoids the need for conrods with split big ends. I am concluding that unless the original design makes specific provision for oiling based on the design and direction of rotation of the con rods, then it probably doesn’t matter.
Those who have a preference maintain that the fork rod (which is rather more asymmetric than that shown in the drawing in the original post) contributes to the oiling of the blade rod big end bearing by scooping oil laden air from the crank case that then finds its way to the bearing. In the case of JAP engines the blade rod runs, or rather rocks, on a bronze bush on the outside of the hardened steel bearing shell of the fork rod. Whilst there may be some truth in this, I am not sure that this can have been considered a principal/critical source of lubrication for the bearing.
Various V twin engines use fork and blade style conrods.
Without worrying about the pros and cons of this style of conrod, does anyone know of a rationale that links the orientation of the rods with the direction of rotation of the engine? There are proponents for both solutions, but is this just custom and practice, or is there an engineering rationale to support one solution or the other?
|Thread: Silver soldering a blind 'mortise and tenon' joint.|
In the original post Robin mentions “tinning” with silver solder. I would be interested to hear Keith’s (CUP Alloys) view on whether this is a viable technique.
In Morgan Three Wheeler land, recovery of used chassis lugs that have been previously silver soldered on to chassis tubes is achieved by machining the tube out of the lug. Removing the lugs with heat is not recommended for fear of “de-zincification” leaving the steel lugs brittle and prone to cracking.
If this is real, then tinning and reheating silver soldered components to sweat them together sounds like it might have the same effect? I would be grateful for any clarification.
|Thread: What MIG Welder should I get?|
So, I had a Clarke MIG machine for many years, and following some minor mods to the wire feed, had reasonable success. Recently I decided to upgrade, but did have some budget. I ended up with a Jasic machine which Is excellent and improved the consistency and reliability of my welding at a stroke.
My advice is buy the brand sold and supported by your nearby “proper” welding shop. You will get advice and support from people who know what they are doing, and know the kit. They will also support you should it go should go wrong, and because of this, should only sell you decent kit. My shop is Brookside welding in Macclesfield.
My MIG machine is close to the bench and it surprises me how often it gets used....
|Thread: What did you do Today 2018|
I am not sure that is “self made” - or if it was the chap made 2!
My mammoth workshop re-organisation turned up what looks to be an almost identical item, although at the headstock end it has a pulley and drive pin arrangement that I assumed was intended for use with a bow?
It was given to me by a watchmaker who was ex bomber command and trained as a watch maker at the end of the war. It does have a hand made look to it, perhaps it was made by course participants as a part of their training?
I put it on the shelf as it is a nice thing, would someone get some use out of it?
|Thread: Odds and sods|
PM me your address and I will pop it in an envelope for you.
Workshop reconfiguration continues making way for my new project and these things turned up.
A strange pair of pliers, curved serrated jaws and a blob on one side. No idea what it is for...upholstery maybe, or is it a farriers hoof clincher! I am sure someone here will know.
Unbrako socket screw data chart, and a James Austin and Son of Dewsbury Double Sharp Weight calculator....a kind of slide rule affair for calculating the weight of steel sections in lbs per linear foot.
Free to good homes if anyone is interested.
|Thread: 3 Jaw Chuck Internal jaws - looking for a home|
Good news! A new home has been found for the jaws.
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