After 6 months now using the Boxford, I`ve decided along with advice of friends and other model engineers that I`m going to stick with this lathe and for the reason I`m investing the next few weeks in refurbishing it to a former glory. I`ve not much money to spend on it but all it should cost me is some paint and the rest is only a case of time and effot, maybe some materials that I`ll already have in stock for re-bushing and such.
Here is the lathe when I first got it and it is pretty much unchanged up to now:
Here is saddle/ carriage removed and full of swarf filled black oil…. aka gunk!
Few more various bits removed as well as change wheels and motor bracket and motor.
Just the headstock left on the bed with the gearbox. It is hard work getting the head off. I`m going to need to make some sort of bent spanner to give me enough lever between the bed! The head has to come off to reveal the screws holding on the gear box.
Old motor is at the top with the newer blue Brook Crompton 3/4hp 3 phase motor that is a perfect replacement! I had a boxford shaper and this 3 phase motor came off it. Luckly I kept it as it is now going to be perfect to install with an inverter to give me variable speed! If you look back at the photos of the headstock you can see the crude on off switch and reverse fitted in a terrible position with bad wiring. This three phase motor will allow me to have vari speed and a neat control box for the unit.
New 3 phase motor detail plate.
So the headstock and gearbox off next once I sort out a suitable spanner!
My last three attempts at wheel cutting have been a steep learning curve. Not centring the cutter, not tightening the wheel, cutter not sharp enough….. A friend over on the Madmodder Forums offered to lend me a hand and so I visited his workshop and managed to make a multi-tooth cutter and cut a wheel. Here are the pics… The method we used I first read on an article by David Creed on making a multi-tooth cutter and also on Deans excellent website: http://www.deansphotographica.com/machining/projects/multipoint/multipoint.html
We have basically followed the instructions and ideas on there but here are the mandatory pictures!
This first one in my opinion was the most impressive. When calculating the tooth arc, we had to make a tool to profile the cutter to represent this arc. I had read that the easiest way of doing this would be to grind the end of a suitably sized drill bit as I have done and shown in an earlier log. Stew came up with an excellent idea of using a magnified projection of the tool to determine the correct size and profile. As you can see from the photo, Stew set up a torch, magnifying glass with the tool inbetween. This allowed us to project the profile onto some CAD drawings of the correct circle diameters. It worked very well and it was supprising how accurate this allowed us to be.
This shows the profiling tool ground to size and shape….. as you can see, it was in use at the time of the photo and hence all the swarf!
Here are all the arbours and jigs made by Stew…..and taken home by me…. THANKS I owe you one!
Another picture of the jig for drilling the 4 holes in the wheel blank….
Cutting the profile of each cutter side…
Cutting away the spare material of the cutter on the other jig…
The cutter straight off the mill…finally made!
And now time to harden! Cherry red and was knocked in a bucket of water:
The cutter mounted on the arbour and starting to cut the wheel. The wheel was mounted on my CNC divider which seemed to work quite nicely.
And the final wheel cut!
Thanks again Stew!
Chris
Still pushing on with this, I have now cut a new cylinder to size and with a better finish from a 16mm OD test-tube with 14mm ID. This is the graphite piston to a perfect polished fit. This is the first time working with graphite and I`m very impressed with the fit!
Wasn`t quite finished in this picture but you can see the mirror finish starting.
This is the graphite bush for the displacer rod.
Since I don`t have a boring head for the mill and didn`t want to offset the plate in the mill, I luckly had this step drill that gave me just the 16mm by 3mm shoulder I needed just to sit the glass piston cylinder inside.
I then turned up two supports…
And here is the insert for the graphite power piston.
<
And what I have so far....
I made an attempt at an LTD Stirling Engine several months ago and failed quite miserably. I know these things are temperamental but after my first attempt I did have quite a few ideas for improvements…nothing new, things that people have already been doing but stuff that I ignored! So over the last few months despite having 101 other projects on the go I started collecting materials. I decided on a glass cylinder with a graphite piston for the power piston and also point bearings as shown in Jan Ridders latest LTD simple stirling plans.
Here is the lump of graphite I`ve managed to get hold of… it is a fair lump!
And it seems to cut OK. I hacked a long block off the top and turned it down holding the vac under the tool to pull all the graphite dust away. This was just a test but I used the same process to make the displacer piston bushings.
The power piston will have a glass cylinder. I needed to know that I can cut test tubes before I got into this and this setup worked a treat. Turning the glass slowly in the lathe I eased the dremel cutter slowly into the tube. I believe you can cut it half way and snap it the rest of the way but I actually held a cloth under it and cut right through.
Here is a collection of most of the materials. The only thing missing is the 2.5mm silver steel which I forgot to include in the picture.
The container was purchased at Asda for £1 and is about 101mm OD. I rang a plastic company and for a 100mm OD clear acrylic piece of 20mm length they wanted £12 plus £10 postage!!!! I think this will do the trick nicely and it cut far more easily than the tapered Tesco spaghetti tube I used last time - the 20mm cut off length can also be seen above! You can also see the glass cylinder.
So I`ve now made some progress with the displacer cylinder, top and bottom have been cut and the top displacer rod hole bushed with graphite. The displacer cylinder will be permanently sealed once completed unlike some designs (and my last attempt) which used screws to clamp the cylinder in place. I think I had a problem with air leakage last time so this time I`ll stick to Jans idea of a permanent seal. I`m actually going to use sealant to permanently bond the bottom section of the aluminum to the plastic displacer cylinder. I`ve cut the top aluminum so that there is a rim of the same ID of the cylinder. This allows me to lock the cylinder onto the rim and I`ll use a small bead of silicon just on the outside join to seal the two as it is held tight without any bonding. If anything does go wrong it`ll be easier to cut this small seal if I need to disassemble the displacer again.
So that is where I`m at right now. My aim is to actually get this finished hopefully during the next couple of weeks. There isn`t an excessive amount of work in it now.
Chris
It was catastrophic failure of all proportions the other day, my mill popped, the switch tripped and the fuse was in 1000 pieces in the fuse holder. I replaced the fuse and the same happened again. Why I thought it would change I don`t know - but I continued to put in a third fuse, stupidly, but to the same effect. After the main symptons of berivement dwindled, those of anger then grief (he is a good friend and solid worker after all), I decided to go see what I could do about it. I did a bit of the usual prodding and inspecting and couldn`t see anything obvious. Then I called in on some advice from Mr Kwackers, a member on these forums. First I was to isolate the board from the power source, the fuse didn`t trip which proved that it was the board that was causing the issue.
This document was very helpful and was also taken from the HossMachine website:
http://www.hossmachine.info/Gerling%20Labs%20X2%20circuit%20board%20ServiceManual.pdf
This is a picture of a complete new motor board, which I did consider buying before Kwackers explained how to start testing it, and at £125 in the UK, not cheap:
Anyway, after determining it was the board, apparently the most likely cause of a dead short was that the bridge rectifier had blown. I desoldered this from the board (which was much harder than it was just then to write!) and tested it. Continuity everywhere between most connectors and therefore the likely cause of the short. I order a replacement on ebay and then being impatient, I decided to see what maplins had to offer in store to take away with me today. Sadly they didn`t have the exact component so again I mithered Kwackers this morning to see if any would do - there was apparently one that would be over rated so I decided to try that. When I got there I found that the casing was different and therefore I`d have to make some fly leads to connect it up the board which was more of a pain but finally looked like this:
I powered up and what do you know, it worked like a dream, almost better than before :whip: .
OK - not the height of electronics enginering but I was pleased, it saved me £125 for the sake of a £2 component! …oh and of course a few beers that will need to find there way to Kwackers. PRobably not very interesting but if someone manages to stumble of this thread with the same problem, I thought it may help them and be worth posting.
Chris
EDIT: will resize those pics shortly but just having a few computer probs, reinstalled windows and no software to do so at present.
After passing my Foundation Licence only a few weeks ago, I wanted to work SSB on 2m and my roof mounted vertically polorised colinear X200 clearly wasn`t up to the job. I decided to try a homebrew 3 element Yagi, the dimensions and details were all provided by Neil, many thanks:
1. Reflector - 1040.6mm long and fixed at the end of the boom.
2. Diven element - 2 lengths of 475.3 - 10mm gap between them. each individual part of the driven element is insulated from the boom and each other.
3. Director - 842.8mm long and fixed to the boom 737mm from the reflector.
I started of with the parts: 12mm steel rod - 2m length, 12mm steel rod - 1m length, 20mm square ally tubing - 1m length, 20mm dia clear acrylic bar.
I then started on the driven element, making my acrylic insert that would slide into the 12mm tubing and provide a 10mm insulated gap between the two. They needed to be a tight fit so that the driven element would remain rigid as one despite the gap.
The insert in one of the sides of the driven element:
Both connected, nice and tight fit and they felt pretty rigid:
Then the driven element was mounted in a box to protect the cables and insulate from the boom:
I then needed to produce some sort of insulating mounts to hold the elements correctly on to the boom. I had some plastic mounting blocks knocking around, so using a 12mm drill I drilled a half circle into a couple of these:
I bolted the elements onto the boom and there it finished - a 3 element Yagi for use on 2m. A brief test portable showed it to work really well but I`ll post more when I have tested again.
I had it running on the slides but thanks to JasonB and his suggestion over on madmodder, I`ve made a simple design to hold the leadscrew nut. It just so happened that I had a few pieces of chunky brass plate lying around from the frames of my clock build so I quickly neatened up a small piece, machined a flat on the top of the nut and silver soldered them together (thanks Drew!) with some screw holes to fasten it to the bottom of the table.
More time spent on the router - I managed to secure the table to the base on the slides (it`ll have to come off soon to fit the lead nut).
This is the lead screw - trapizodal with nuts ordered from MerchantDice on ebay. Excellent delivery - I ordered 10am and it came 11am the day after!
It runs on bearings at either side of the bed with plenty sticking out of one end for the motor:
Here is the lead nut - I now need to secure it to the table with very little room between the table and bed.
After seeing my mate Steve’s router out of the corner of my eye one visit back during the Christmas period I`ve been frequently going on cnczone to eye these machines up. As is usually the case with the internet, and that is part of its brilliance, there are countless ways to make these and every time I`ve been close to getting started something has put me off. When my brother-in-law started to build one back a few weeks ago that just tipped me over the edge with determination and I had to make a start!!
My plan is to build a fixed gantry machine so the table with move on bearing draw slides (kindly donated by Steve - cheers mate!!) These are heavy duty draw slides and are like nothing I`ve seen before, certainly nothing at B&Q! For the other two axis I`m going to use ground 1/2″ drill rod running over home machined phos. bronze bearings. It certainly sounds good, I just hope it works!
The router will be made almost entirely out of 3/4″ MDF.
I took my plans earlier today to the hardware store who cut all the bits I need for now:
Here are the draw slides:
I then I cobbled together the main base and base stands to just lift it iff the ground:
And the length is due to the length of the draw slides:
Lots more to do but it is a start!
I ordered the Knole DC RX a couple of week back from http://www.users.globalnet.co.uk/~walfor/simple.htm
The kit arrived within a day of ordering and then it sat on my work bench for some time while I plucked up the courage to take the soldering iron to it.
So many holes, so many components and so little radio knowledge!
Instructions are incredible, lots of detail and nice preamble just to set the scene for the build. PCB has no silk screen and this was a little daughnting at first but the excellent instructions and component layout diagrams makes up for this.
First step was to setup the mechanical parts on the front panel.
Then tack solder the panels together. This was much harder than I expected and it didn`t look as clean as I was hoping at the end, but pretty solid and secure.
First step was to setup the voltage regulating part of the circuit and turn it all on and check voltages:
Then onto the output stage:
And finger/screwdriver buzz test:
Finger buzz test worked fine and voltages the same so it was OK to continue to the VFO and toroid winding!
and that is where I am up to so far. I haven`t got a frequency counter so I`m now a little stuck trying to tune in the VFO. Apparently for the 40m that I am trying to set this up for require a VFO freq count of between 5.0 - 4.8 MHz. I have just managed to get hold of a yupiteru mvt-7100 scanner and I can apparently use this instead of a counter….I just need to figure out how!
Recent Comments