Although I have a Moore and Wright depth micrometre, I recently needed o check the depth of a hole that I was drilling which was much smaller than the rods on the depth mic.
I had seen a video on YouTube where a gent in the US made a simple depth gauge from a length of aluminium bar stock , a thumb screw and a length of rod.
As luck would have it I recently bought some 2mm silver steel rod for use as retaining pins for gearboxes I also had a piece of 10mm x 100mm x 14mm rough cut piece of mild steel which was left over from my lathe upgrades. The rough cut edge was actually along it’s length rather than one end (although the ends were not perfect either.
Due to the need to mill down the stock to square up the rough cut edge I thought it worth trying my hand at milling some angles along what would become the top of the gauge.
Sadly when I came to drill out the hole for the measuring rod the 1.9mm drill wandered of line and the hole although square front to back was a little off to one side. Although it was not out enough to stop it being functional it bugged me so in the end I mounted the body in a 4 jaw chuck in the lathe and used a 4mm diameter end mill to open out the hole and square it up. The end mill wasn’t quite long enough. so I had to run a drill through the last millimetre, but by then the hole was square and the problem was solved.
Finally I turned a nickel silver bush to fit the hole and them drilled that out 1.9mm and reamed it to 2mm for the measuring rod.. A turned brass thumbscrew completed the job.
The flutes on the head of the thumbscrew were machined using my Proxxon dividing head on the mill table. I made a second smaller thumb screw for the end of the measuring rod so that it didn’t poke my in the eye in use. Lastly I blackened the body of the gauge using Birchwood Casey Gun Blue
Still beavering away making slow but steady progress. Next up were the front bogie top bearers (or that’s how they are referred to in the instructions) and the fitting of the bogie itself. The former were easy, tin with 100 degree solder and use the RSU to heat from inside the frames.
The bogie fitting was a little more challenging. My fitting of the representation of inside motion had scuppered using the method that the kit provided. At Guildex I had a chat with Nick about how he had done his and he confirmed what I had thought would have to be the solution. Which is do it like the prototype (simplified of course) and fit a plate to the bottom of the frames. This proved challenging because of my seeming inability to drill a hole in the middle of a rectangular plate… It took three attempts before I got the hole in the ruddy middle. Actually, I am being a bit hard on myself. The first one was in the middle it’s just the plate was too small…
With the part finally ready to be fitted I turned my attention to the mounting screw and the ‘nut’. The kit comes with a nice turned elongated top had type bush which is threaded 6ba in place of a conventional nut.
I had already made the side control springing block to accept this threaded bush so I wanted to use it. However now that the fixing point was much lower in the frames.
What I couldn’t work out was whether the bus was threaded all the way to the bottom of the hole or not because I didn’t have a long enough 6BA screw to check. So rather than trying to shorten the existing bush I thought it easier to turn up a new shorter version. I also turned the first 0.45mm to just fit tin the hole in the mounting plate which is slightly larger than the screw.
Despite my messing about for quite some time with a stack of washers trying to work out how long the shortened bush needed to be, it ended up slightly short.
Thankfully I had the foresight to leave it attached to the rest of the stock so once I worked out how much longer it needed to be, it was and easy job to turn another 2.5mm down to the same diameter. A short length of spring allows the bogie to float up and down by about 1mm.
Having got this far there doesn’t seem to be much in the way of swing before it hits the inside of the cylinders but this may change when on track and the side control does its job. Time will tell whether I need to cut back the cylinder wrappers.
When making my mini tap holders some time ago, there was a discussion about making, versus buying tools over on Western thunder, where I mentioned that I could buy one from Arc for under £10. I duly bought said tap follower from Arc Euro Trade and what a journey that turned out to be. When it came the grub screw in the image fitted into the back of the tap follower to retain the spring.
Which in itself was fine aside from the fact that the body of the tap follower was too big to fit in either of my Jacobs chucks and although I could have swapped the chuck out for a collet chuck that would have been a lot of messing about each time I wanted to use the tap follower. My solution was to turn up a threaded pin to replace the grub screw. Which on the face of it is simple, except I couldn’t determine what thread* was in the tap follower as supplied, so I ended up re-tapping it to M10.
That done I gave it a whirl and found that the hole in the body is far too big with too much slop for the guide rods to actually hold the tap straight. Which of course is the whole point of the exercise…
Hopefully you can just make out the gap between the two in the close up below. What should be a close sliding fit is far from it.
As I had already modified it I couldn’t really return it to Arc Euro so I put it in a drawer in disgust and moved on.
Fast forward to a couple of days ago and I had need to tap another hole in the lathe and I just happened to have the length of 8mm stainless rod (which I use for tightening my collet chuck) in my hand when I saw the tap follower in the drawer. I took it out and quickly dismantled it and tested the 8mm rod inside the body of the tap follower. It was a perfect fit. I cut another length from the piece I have in stock, to suite a new double ended guide rod and then turned each end down to a close sliding fit. One end has a point, the other has a 60 degree countersink to accommodate taps with points on the end.
Now I have a tool that does what it was supposed to when I bought it. I cannot blame Arc for the initial problem of the shank not fitting my drill chucks because it does state the shank size on their website but I missed taking note of it.
The poorly fitting guide rods is another matter.
You live and learn and I suspect that in this instance I would have been better making my own tool or buying a better quality example in the first place. At least I have been able to remedy it and I may at some point make up a second shorter version to utilise the spare guide rods.
*Having checked the Arc Euro Trade site as I was typing this to confirm that they do indeed note the shank size, I also noted that all the other measurements although primarily stated in millimetres, are in fact conversions of imperial sizes.
As I don’t possess any imperial taps or dies I was doomed from the start in working out what size the thread might be.
A few more micro fixings later saw. a major milestone both mentally and build wise.
These are the pins which hold the eccentric rod to the bottom of the expansion link. Initially I made the two fully threaded versions but then realised that it would be better if they were only partially threaded (14BA).
I had already fitted the return cranks and after this it was a short step to getting the full motion running.
I mentioned in the post above that I also had an Eclipse scribing block. This was a gift from a friend when he was moving and I was very grateful for it. I am a little ashamed to say that aside from using it a few times with my indicator I have done very little with it.
Having discovered the WD40/Ultrasonic Cleaning method I decided to see if it was a fluke or whether it really needed the soak in vinegar first.
Because it was a test I took a few more before and after photos
I put all the smaller parts in the pot of WD40 and ran it through the US cleaner for half an hour. When they came out the dirt was loose, but they were not as clean as the items that had been pre-soaked in vinegar.
On the bright side, I gave them a rub over with ScotchBrite and the dirt came away easily with almost no effort. A second run through the US cleaner had them like new.
I did the main column with WD 40 and ScotchBrite which did take a bit of effort.
Hello I’m Rob and I am a tool junkie… or so it might seem.
During breakfast and morning coffee I have taken to watching YouTube videos on machining, restorations etc. while Chris catches up on the news and current affairs.
While watching one such video a gent in the states who has a superb machine shop that he inherited from his Grandfather was making an adjustable indicator holder.
The resulting tool was excellent, but as it was nearing completion I couldn’t help but notice that the design was pretty much the same as some adjustable scribing blocks that I had seen on eBay while searching for Moore and Wright tools. Sure enough a search on Moore and Wright scribing block brought up several, ranging from one with some parts missing for £10 up to pristine boxed examples that were almost £100.
I found one that was complete (if rusty in places) but unboxed, that the seller was asking £15.99 plus P&P for. I put it on watch while I browsed further. As per a number of my recent experiences, by the time that I had found a couple more at sensible (to me) prices, I had received a lower price offer from the seller of £12.99.
Offer and counter offer is one of the functions of eBay that I really like and I have used it to negotiate a better price on a number of occasions. Being a tight Yorkshireman, I decided that I didn’t want to pay more than £10 plus P&P for it but knew that if I counter offered £10 that the seller would in turn counter with £11.
So I offered £8. My thinking being that the seller would then counter with £10 and sure enough they did. Result and a happy bunny.
On a side note, I think that if you enter into negotiations like this, it is only good manners to buy the object in question although I don’t always take up the reduced price initially offered as sometimes I just put items on watch out of curiosity with no intention of buying them at any price.
This is what it looked like when it arrived
I stripped it all down and put all the small parts which were rusty into a pickle jar full of white vinegar (we bought a gallon of it a while back). I left them for 24 hours and then brough them out and cleaned much of them with ScotchBrite but there were lots of small parts and springs that were either difficult to hold or lot’s of small crevices etc, to get into.
Then I recalled another video that I had watched, where a gent (again in the US) with an decent sized Ultrasonic cleaner had put various objects into small pots of different detergents including one of gasoline. These containers were then placed in the US cleaner which was part filled with water and turned on with really good results.
Another recent purchase was a 5 litre bottle of WD40 so I decanted some into a small container dropped in all the small parts and gave them a 30 minute cycle with the container surrounded by water (approx. 3/4 of the way up the container and above the level of the WD40) but no additional heat. I say no additional heat because my US cleaner has a temperature dial which goes up to 20 degrees, but even with the temperature set to zero, it still gets quite warm.
I was absolutely blown away with how clean the parts came out and the added bonus of using WD40, not only does it clean, but it doesn’t send the parts rusty like detergent or other cleaners might.
As you can see below there is still some pitting and general wear marks, but from any kind of distance it almost looks new.
Now as I mentioned at the beginning the plan is to use this as a dial indictor holder rather than a scribing block as I already have a nice Eclipse Scribing block that a friend gave me. More on that in another post.
This is the finished and reassembled tool fitted with a dial indicator.