Monday, February 1, 2016

Practice.... May Eventually Make Perfect

I've now owned a lathe for over a month, but until Saturday all I'd done was strip and clean parts of it, I hadn't actually tried using it to turn or drill anything. Part of the problem was not really knowing where to start. You can read books and watch videos for hours and still miss really obvious things that can be the difference between success and frustrating failure. Also having made the investment the last thing I wanted to do was damage the lathe on my first attempt at using it. Fortunately Paul very kindly agreed to visit at the weekend to help get me started. So in between copious mugs of tea/coffee and slices of cake I finally turned the lathe on in anger to cut some brass.

Sensibly we didn't just shove some brass and a tool into the lathe we spent quite a bit of time checking it over and figuring out if it had any little quirks; like there is a bur inside the headstock which stops larger bits of brass sliding cleanly inside the shaft and which I need to look at sorting at some point. When we did make a start though we didn't mess about and went straight to turning a 7mm diameter wheel. This isn't as daft as it might sound as it turns out that the basic steps in making a wheel form a nice introduction to turning. You need to make some drawings first to figure out dimensions, then there is some facing and turning down to different diameters, then the use of a profile tool, then some drilling for an axle, and then parting of the wheel. In other words a nice introduction to lots of the common tasks I'm going to find myself doing on a lathe.

I didn't take any action shots, but these two nicely show the drawings and jottings as well as the finished wheel and a brief experiment in taper turning. I did make a few mistakes as we went along, so the wheel is far from perfect; mostly I didn't lock the tool post tight enough when parting off so it slipped slightly meaning I lost part of the flange. Of course the real test will be to see if I can repeat the process without Paul around to help, but that will have to wait. One of the problems we did discover is that the parting off tool I bought is huge in comparison to Paul's. Mine is just over 3mm wide whereas Paul's is closer to 1.5mm. Given the size of things I'm turning losing 3mm of brass is wasteful and will also put more strain on the motor. Fortunately Paul has kindly taken mine away to grind down so it's more useful as well as grinding more clearance on the left hand turning tool.

As well as turning we also fitted the milling attachment to check it also worked, which it does. Here you can see it in place and also see that I've bolted the whole machine to a chopping board (it was the best thing I could find), although from using it on Saturday I need to fit some rubber feet to stop is sliding around.

As well as showing me how all the tools and accessories I have work Paul also brought some of his tools with him so I've now seen how an indexing attachment works, as well as a collet chuck and some interesting step chucks. I can easily see all of them being really useful but I'm not going to buy any more tools until I've learnt to use the ones I have, or have a specific need for one, otherwise I'd quickly end up broke!

So, thanks again to Paul for driving over (and back in the snow). I really enjoyed meeting him, talking modelling, and learning to use the lathe. Hopefully he enjoyed himself too, or at least the cake!

Saturday, January 23, 2016

3 Jaw Chuck

So far this year I have had almost no time for modelling as work has been rather crazy because the project I'm currently working on is drawing to a close. Hopefully once we get into February I should have a little more time. This also means that I still haven't had a chance to do anything with the lathe I bought just before Christmas. In preparation for having more time though I've just spent about 15 minutes stripping down the 3 jaw chuck on the lathe (which will be used to hold the things I'm working on), cleaning, oiling, and putting it back together. Given I haven't anything else to blog about I thought I'd show a couple of photos of this.

The first step is to remove the chuck from the lathe. To do this I had to remove the plastic cover over the belts to expose the pulleys and the end of the spindle. A 4mm bar is then inserted through the hole in the spindle and another into one of the holes on the edge of the face of the chuck (not the hole in the ring on the chuck). Holding the pulley steady with one bar I applied pressure downwards on the other to rotate the chuck ant-clockwise. Once it starts to turn it's easy to unscrew the rest of the way by hand.

Once the chuck is removed from the lathe then next step is to remove the 3 jaws. This is done by turning the ring anti-clockwise which opens the jaws. The more you turn the further out the jaws move until they can be removed. Each jaw is numbered and number 3 drops out first, followed by number 2, and finally number 1. With the jaws removed everything was carefully cleaned using whitespirit and left to dry before a few drops of 3-in-1 oil was used to lubricate the mechanism.

To reassemble the chuck you need to turn the ring until the edge of the screw is just to the right of the gap for the number 1 jaw. Slide the jaw in and then turn the ring slightly so it grips the jaw. Repeat for jaw number 2 and then 3 before then continuing to turn the ring clockwise until the jaws are as far in as you need. The chuck can then be screwed back onto the lather headstock spindle ready for use.

Wednesday, January 6, 2016

An Investment

When, much to my surprise, the first batch of Hudson-Hunslet kits proved so popular I decided that I'd invest at least some of the profit in some modelling tools. So far I've worked purely with hand tools, I don't even own a Dremel or similar tool. While there were a number of options I considered (such as a Dremel), in the end I decided that what I really wanted was a lathe. Unfortunately I knew nothing about either buying or using a lathe. Fortunately Paul does and has been very patient with me as I bombarded him with lots of questions. The upshot of our many e-mails is that I'm now the proud owner of a Unimat 3.

As these lathes aren't made anymore I had to wait until a suitable one popped up for sale, in this case on eBay. This one was very reasonably priced although it didn't come with any tools, the milling attachment or even a manual. Fortunately free scanned copies of the original manual (plus the manual for the other Unimat models) are freely available here.

I now have a few tools on order (also thanks to recommendations from Paul) so as yet I haven't tried using the lathe although I have replaced the belts (they were showing serious signs of age) and checked it runs okay. Next up will be to order some brass so that I have something to practice on when the tools arrive, that and tidying the garage so I can set it up in a slightly more sensible environment.

Sunday, January 3, 2016

How Big is a Bee?

Given we are now into 2016 I only have eleven months left to build my entry for the NGRM Online challenge. If you remember my previous post then the challenge is to scratch build a loco and I'd settled on modelling Bee from the Great Laxey Mine Railway.

Before I can make a start on the model I needed to decide on the scale I was going to model in. My gut feeling, given the tiny size of the loco, was to jump up another scale from my previous modelling and work in 16mm to the foot scale. To check out how sensible this looks I scaled the side on drawing I have to 4mm, 7m and 16mm scale.

The driver figure is a 7mm to the foot scale model to help give some idea on size etc. As you can see trying to model in 4mm scale would have been insane. Working in 7mm scale might have worked if I was 3D printing or etching parts but I think it is still too small for a scratch built model. The jump to 16mm scale though gives me lots of space for a nice sized motor (either horizontally or vertically) and should let me go to town on the details etc.

Having settled on a scale I've also been thinking a little about the track I'll need to build to show the model running. The prototype is 19" gauge using 20lb rail. If my maths works then I think that means I need to produce track with a gauge of 25.33mm using PECO code 143 rail, although I've yet to figure out the size of the sleepers that will be required.

Saturday, January 2, 2016

Hinge Versus Flex

When I built my first working point at the beginning of December I mentioned that I was intending to build another one to see if relying on the rail flexing was a better approach than hinging the rails. I actually built the second point quite soon after but for some reason didn't post about it. Anyway here we have both points next to each other with the new version no the left.

So how does allowing the rail to flex compare to using hinges? Firstly aligning the rails accurately and getting a nice smooth curve through the point was much easier the second time around. Partly this was down to having a better idea what I was doing when shaping the rails but also as I could use the rail gauges to position and hold the rails in place while they were soldered on which was easier than holding them in place and drilling holes for the hinges. On the down side though I'm honestly not convinced by the motion of the point. Firstly as the rails are flexing I've ended up with a point that when left alone sits with the tie bar half way between the two routes. Secondly keeping the point one way or the other requires quite a considerable amount of force.

So in conclusion I'm going to stick with fitting hinges to the points and hope that with more practice the flow of the rail will improve slightly over the first attempt so I'll have both nice looking points and points that require little effort to operate.

Friday, January 1, 2016

Meanwhile in Rhyd

Thanks to a local reporter (i.e. David the owner of Rhyd) news has reached me that the Clayton arrived safely in Rhyd after the long road journey from Sheffield.

By last Saturday she had been unloaded onto a flat wagon for the journey up the quarry tramway.

The battery was charged and she was given her inaugural run up in the mountains.

After running in she will be entering the paint shops - but she will be back in service long before Model Rail Scotland in February.