Member postings for Stuart Bridger

My first proper job, post apprenticeship was in the "Electronics Maintenance" shop at Brooklands (BAe Weybridge) One of our tasks was repairing Avo's, there were many 100's in use across the site. Any that failed calibration or got damaged came to us. The worst job was setting up the overload cut-out. This was a fiendish mechanical system, that relied on the acceleration of the moving coil needle to trip the spring loaded cut-out button. They had to be carefully adjusted to ensure that they didn't nuisance trip, or not trip at all, damaging the meter. I still have a Pan Climatic Model 8X, which was the spec supplied to the the forces, but haven't used it in over 20 years. My Fluke 77 DMM gets used for everything I need, but I don't do stuff that needs to be able to see a trend, for which you cannot beat an analogue meter. The Avo 7's and early MK8's were very well made, solid as a rock, unless badly abused. The newer 8 Mk V (if my memory is correct) was horrible, internally it used a new technology of a flexible PCB that warapped round the inside, instead of the point to point wring of the earlier models. Unreliable and very dififcult to work on.

My response was a bit off the cuff. Given more time, I could be a much better model engineer. I am working too hard, have a busy social life and have a number of other hobbies. It took me 6 1/2 years to complete my first model, a Stuart 10V. That included setting up my workshop. Mind you before that I took 20 years to complete a Billing model ship kit. Golden rule is no machining when tired, which tends to preclude weekday evenings. Need more time....

Time...

Given that you are looking for a generator and you have a 3 phase lathe. Why a single phase generator?
A 3 phase genny will be more expensive than single phase, but you won't have the additional cost/complexity of changing the motor or adding a VFD. I echo the previous poster's comments about speaking to a hire company for advise.

Hi Paul,

Check out https://inverterdrive.com/HowTo/inv/

and https://inverterdrive.com/HowTo/240V-Supply-to-a-400V-AC-Motor/

For some very good explanations as to how inverters work

As an aside, I run the original 400V motor on my Chipmaster using a 240V inverter based on the technique describe in the second article.

Stuart

Edited By John Stevenson on 13/07/2016 23:06:00

A couple of points come to mind

1) Are you sure that the voltage is constant? Most inverters vary both voltage and frequency.

2) what is the frequency response of your clamp on meter, it may only be accurate at 50-60Hz

Slight OT, but "new and unused" doesn't fit that photo

Thanks Nick, I watched your video of the completed model a couple of hours ago. Nice work! James Coombe is looking a very attractive proposition.

Thanks Martin, I had been looking at The James Coombes

Roy, to be honest, it was lack of plain steel nuts and making use of what I had to hand.

I have finally completed my first model, a humble Stuart 10V. While not up to competition standard, I think I have done a pretty decent job. It runs nicely on air and the finish came up well. The wife has even allowed it to take pride of pIace on the mantelpiece. I have learned and re-learned a lot during this first foray into model engineering. It wasn't without challenges and there were a few components scrapped along the way.

The big question is what to tackle next? I think I would like to stick to stationary steam, but would like something that will challenge me further. Any suggestions on suitable kits or even plans from scratch for a next project? I have a reasonable capacity with a Chipmaster and a Warco VMC, so could tackle something with a larger flywheel.

Incidentlayy the base was cut from a low cost beech chopping board from a supermarket finished witha gunstock oil.

Back in the '80s we had a scrap bin ouside the apprentice training school at Brooklands (BAe Weybridge).
Very strict rule was that only solid metal could go in, no swarf. From memory the only swarf that was recycled was the high output of known alloys from the skin milling shop, whach was collected via a vacuum system.

Probably not much help, but I also put extensive research into a DRO for my Chipmaster. My decision was not to bother. The installation was going to be a hassle and I never really came to a good solution for the amount of space the cross slide scale would take up. Even more significantly I found with more time on the lathe that I really didn't need a DRO. I do have a DRO on my mill though and would not do without it.

One of my very earliest memories, being taken to a "Scramble" (not Motocross in those days) with my parents. Having a picnic with cold sausage sandwiches, that tasted of Castrol R, there was so much in the air. Even just a whiff brings back very strong memories.

I did a stint in Electrical Drawing Office during my apprenticeship at Brooklands, circa 1983-84. I was mostly doing modifications to existing drawings. All on drawing film with ink using Rotring pens. Erasing existing lines, etc with an abrasive rubber and then doing the update. Most time consuming was doing the change notes with stencil. epecially if an error was made. Looking back on it it there was some incredible skill involved, but it was horribly inefficient. CAD was just coming in at that time.

Thanks for the feedback Jason. I was turning, about 50 thou DOC and tried 2 and 4 thou per rev feed

The vast majority of turning on my 1963 Chipmaster has been using home ground HSS, with the exception of a couple of boring bars with inserts. I spied an advert from Arc Euro with insert based turning tools at a very attractive price. So I invested in a 16mm shank turning tool with a CCMT09T304 insert and thought I would give it a go.

So said tool arrived and I mounted it up against an offcut 1.25in of (I think) MS bar from my friendly engineering shop. Cranked up the Chippie to scarily fast speeds (2000ish RPM) and off we went... "interesting" times.

1) Neat cutting oil is not ideal for this task clouds of smoke obscuring my view of the job and filling the workshop. Conventional suds would be much better. Also coolant splashing around everywhere.

2) Hell I need an insert witha chipbreaker. Streams of very hot curly blue swarf. A real tendency to come off the insert and route behind the toolpost screws and shoot out horizontally very close to to where I was standing. At the end of the job it wasa really good excuse for a major sweep-up of the workshop and I am still finding little blue black spirals in obscure places.

3) Boy did it make my Chippie grunt, don't think the Inverter has every run so hard and it did slow the spindle speed significantly.

4) Whoa the workpiece didn't half get hot...

5) On a positive note, really nice finish on the work and it certainly can shift material.

So an interesting experiment, I can certainly see why HSS is recommended over carbide for smaller lathes. I won't be completely swapping over to carbide, but will certainly be finding an insert with a chipbreaker before doing any serious work.

The "classic choice" would be a Dickson type. I have a Dickson clone on my Chipmaster (T1 size). The origin of mine is unknown as it came with the lathe and it has no markings, but its solid and works well. The Student I believe would take the larger T2. A decent clone from a maker such as Bison will leave you a very deep hole in your wallet, especially as you will need a decent quantity of holders to make quick change work for you. I would recommend avoiding the cheaper clones. I bought some cheap toolholders to add to the couple that came with my lathe and they are not very good, very poor threads for the clamping screws and not the greatest fit.

If the OP is from the US, the equivalent of the Warco VMC is available from Grizzly as the G0801.
I am also a happy VMC owner.

From memory, it was the EMC filter that was likely to trip a RCD rather than the inverter itself. I do have a separate EMC filter on my inverter.