Member postings for frank brown

Thats brilliant Jason, Did you have just do it graphically?

Frank

So I have a cottage in a wild and windy place with an en-suite. I have built a heat recovery system for it which seems to work. My problem is that for 23.5 hours of the day, heat is escaping from it. So it is always cold to start off with and so I thought I need a way of sealing the air ducts when not in use.

I have built a prototype which is a geared down induction motor (as used in washing machine timers etc.) driving a flap that moves through 90* to open or seal the 4" air duct.

The motor which only starts and stop and runs in one direction is 46.6mm from the hinge pin of the flap. At a distance of 17.02mm from the centre of the motor shaft is a bearing onto a connecting rod of 40mm centres. The connecting rod then connects on to a disc ,24.4mm from the centre of the flaps hinge.

I have mounted microswitches on the other side of the flap so the motor only stops when the flap is open or closed. The whole thing works beautifully, with a change over light switch the flap opens an closes.

There is no slop to speak of in the con rod bearings, but I am worried that when I proceed to invest in stainless steel shafts etc, that the whole thing will jam up. So I thought I would do maths on the various bits and pieces to prove to myself it can work. But I can't seem to even get started.

So has anyone seen a con rod mechanism working on unequal swing arms and its mathematical proof?

Frank

My S-I-L was using a hammer and a piece splintered of the head like Speedy Builder's. He had to go to hospital by ambulance and was treated like a VIP, because it was like a bullet wound, all sorts of Docs came to have a look. He is patched up and more or less fixed. The shard of metal is still in his groin and causes him some discomfort, intermittently.

Frank

Yes I think Michaels link is very close, The colour will be harsh for me I prefer 2700, which is close to daylight and I personally think the light output, while an improvement on the present, is too low for me, but that rather depends on the size of the room and its decoration colour.

If you research the web, you will be able to get the lumens of your existing tubes and the light required for a kitchen. I did this years ago when I converted 10 down lighters from halogen to LED. They paid for them selves 18 months ago!

Frank

How about turning the recess in the quadrant by making a template with a 15mm recess in it and fixing it at centre height in place of your fixed steady. Now make a follower the same shape as your lathe tool fixed in the right hand position of your toolpost. This now limit your lathe tool position to that require. Mount the quadrant on your face plate. Should work but will be a be clunky.

Frank

Flat horizontal surfaces can trap bubbles. Pre-warming the mould might help with this.

Frank

I have had a Churchill Cub for 30 years, it had a 4 way tool post with a big gap, it could take tools up to at least 5/8". I used to find that it would take me longer to shim up the selected tool then to do the job, such as parting off a bit of tubing.

I found thats it is the total number of shims in .005" steps up to 3/8" that I found frustrating. So you have to use a 3 or 4 mm shim then a pile of thinner bits. It would be nice to keep the shims with the tool, but I simply have not got that number of shims in all thicknesses.

I bought a T2 set from Chronos as a Christmas present from the wife and an extra pair from the kids. Fantastic! from the first use it was a revelation. One of the toolholders was faulty, insufficient clearance for the piston, but 5 minutes with an angle grinder sorted that. The only grumble I have is that the locking screw for the height, is the same as the tool locking screw. I have absently minded released the height lock rather then the tool lock. When I get around to it I shall change the height locking screws to an Alan headed grub screw, so an Alan key will be needed to do any height adjusting.

So far so good .

Frank

I can not find it on www.lathes.co.uk, I expect you have looked there already. It did say that some " Clarkson" T&C grinders were rebadged as Smart and Brown. This leaves one to wonder if it is some one elses model that has been rebadged.

Frank

I am not sure about the very fine swarf, Have you got any side relief on the tool? It could be that if the tool is not exactly at right angles then one of its sides would rub and produce the fine stuff. I use WD40 to cut ali.

Slipping belt, need more friction. What sort of belt have you got (flat or vee). The traditional way with flat belts is to use a patent compound or rosin. Vee belts should "dig" further into the groove so the friction increases.

Frank

So its an ex circular saw motor and switch. Just thinking aloud. Circular saws have a lot of inertia and as mentioned, only run in one direction. So how about a start relay inside the box. You switch the motor on on one set of windings, then once another set of windings generate enough voltage, the start cap is taken out of circuit and an additional winding is switched in to get the motor up to full speed (and power). The inrush current from a 1 k motor with a direct mains start would be a be too much for a 13A fuse [inrush ~5 X running current].

So is there a relay inside the box?

Frank

At one place where I worked, "Fred" was deemed to be the "expert" on one job. He was not a secretive type, rather, he was always helpful. So in my youthful enthusiasm I got involved with helping him. His explanation of what he was doing was not at all convincing. In a word he was winging it, but eventually came up with an acceptable result. His being the "expert" was just a title to allow him to do the job, which every no one else wanted to get involved with.

So secrecy might be just a cover for people who don't really understand what is going on. As in "I can't tell you that" (because I don't know).

Frank

An alternative answer:- We had many motors that had the PTC embedded in the windings. The nominal resistance was 600 ohms. perhaps as many as 10% of them failed by the thermistor going O/C due to the temperature cycling of the windings crushing the poor little thing. So the motors were initially rewound with new thermistors. Later we just wrapped the motors in "Fire Wire" . This is a special two core cable that goes short circuit at 70 degrees C.

Perhaps your thermistors are open circuit and there is nothing else wrong with the motor?

Frank

Using Google, I entered "change colour of tiles win 10" and got 865,000 hits, could not be bothered to read them all.

Frank

Containing cutting coolant?, never thought much about it. My thoughts are to get a length of "Corex", its like corrugated cardboard, only plastic. Fold it around (corrugations vertical) so it sits in the outer drip grooves of your mill, bolt overlaps together.

For hand fed coolant, I use a cyclists drinking container with about 7" of hardish 3mm diam. tubing PVC to get to odd places. This pipe is sold as " boom tubing" in fishing tackle shops.

Frank

Judging by the number of connections to that "box", the red knob should reverse the motor. Is it stuck or not working in one direction? The normal wiring is that L&N go to the run windings. One end of the start windings goes to the start capacitor. Depending which way the L&N are applied to the free connections of the start components , the motor will change directions.

Can you find which windings are which with a continuity meter?

Frank

If you want to use a VFD then you need to use transformers to get from 230V to 38V. Each rated at 200W.

Your motor has a "resistance" of 38^2/ 133 = 11 ohms which is not a million miles from 8 ohms of a loudspeaker. So what I am suggesting that a pair of 200W audio amplifiers driven by a variable oscillator which has the phases of its output correct could be another way to go.

Or if you are really clever you build your own VFD

Frank

If your static converter also steps up to 440 3 phase, then you switch the motor of by turning the converter off. Else a, the start caps won't be switched in and, b the back EMF from the transformer will blow up your capacitors (guess how I know?)

Frank

I am that sort of quandrary, V W Passat Estate 190 K miles, 06 plate, Wife and mechanic (S-I-L), want me to, for myself, I am still putting building blocks , sand and cement in the back so am reluctant. My Passat is a nice drive, but unreliable but having sorted various things , I hope it improves.

Frank

Best thing to do is to closely inspect the board with a jewellers eye glass. what you are after is a solder joint where there is a ring around the component lead. This is the air gap that is stopping it working, just needs touching up with soldering iron.

Frank

You can try using pads of roofing felt. If you fancy it, you can get abrasive blocks from builders merchants, about 8" X 1 1/2" X 1 1/2" with two deeply ridges sides, they will grind away concrete. Much less mucky then a disc cutter with a grinder stone. This could be the modern replacement? :- http://www.ebay.co.uk/itm/Silverline-Silicon-Carbide-Rubbing-Block-20-Grit-261034-/121548522005?_trksid=p2141725.m3641.l6368

Frank