Member postings for Rod Renshaw

Hi all

Can I ask what readers think about the need for cleaning the joint surfaces before silver soldering which has been mentioned in passing several times in this thread?

The writings of the late Tubal Cain emphasised the need for absolute cleanliness, and he quoted the relevant British Standard in his own support.

Conversely, the chap from Cup Alloys who delivers the excellent lectures at ME shows, and who is clearly very experienced, seems to feel that the flux will clean the metal at brazing temperatures so cleaning is not important.

Regards Rod

Martin Cleeve was the pseudonym of a contributor to ME in the 1960s who designed and made workshop equipment, including some large items like a full-size drill press, from bright mild steel sections held together with homemade mild steel capscrews. Many of these projects had T -slotted tables fabricated in this way. I made one of the simpler projects, a T - slotted milling table for the lathe. This worked well as far as ease of making and strength in use was concerned.

I think it will take some serious heating system to get workpieces this size up to brazing temperature, and then there is the cleaning up and the risk of distortion. Welding may be possible, I don't really know, but might it leave hard spots which would make the T slot cutting difficult,

so +1 for the glue and screw route.

Rod

Thanks to all who contributed information or opinion to this thread.

Thanks

Rod

Hi all

I am planning to go to the London show and wonder about the easiest way to get from London Euston to Alexandra Palace. Is it simpler to go by rail via Kings Cross and change at Finchley Park or go by underground to Wood Green? Are there local buses from either station to AP, do they take cash or do I need a travel card? Is there a daily travel pass which would serve for all my local travel on the day, and if so how can I get one? any advice or information welcome.

Thanks

Rod

Hi all

VFDs are the way to go, the variable frequency aspect is enough to make them more useful than earlier types of converter.

The ability to vary the speed of the cut at the twist of a knob is a huge time and irritation saver - it almost eliminates the need to shift belts or gears, and it can be done even during the cut to improve the finish and eliminate chatter.

I used one VFD for both lathe and mill back in the day when VFDs were much more expensive. I used plugs and sockets to "switch" between machines and I did not hurry the changeover. I think this helped to reduce any chance of damage by voltage spikes and I had no problems. Worked OK in a one-man amateur shop where it typically takes much longer to tool up the "new" machine and transfer the workpiece than change the plugs.

Rod

Hi

I tried putting the description of the item in UK Ebay and found 8 apparently similar items, but at prices ranging from £3.99 ( +postage) upwards. Must be modern marketing at work.

Rod

Hi

It seems to be accepted wisdom that one should use a new file first on brass, and then relegate it to use on steel once it has lost its initial sharpness.

Where, if anywhere, does use on alloy or plastics come in this sequence?

Rod

Just a thought, but the late JA Radford, a friend and contemporary of George Thomas, published a design which gives a similar effect to the Arrand quick change toolholder. He called it a "quick-change toolholder for the lathe tailstock". It's in his book "Improvements and Accessories for your Lathe" and the design was originally published in ME in about the late 1960s or early 70s. It's intended for home shop construction and is Myford sized. It uses a different method of attachment, using a dovetail slide, reminscent of a "Dickson" type Q/C holder, at right angles to the the lathe centre line. The toolholders, of which he describes many types, lift/slide vertically out of the mounting block so requiring no winding back of the tailstock, just like the Arrand type, Might be easier to make, - did we decide if Arrand are still extant?

Can I thank everyone who has helped to answer my question about switching for my VFD. Now that several of you knowledgeable chaps have had sight of the Manual and have determined my VFD has no provision for using separate Stop and Start buttons I will use a relay as first suggested.

I will search among my (small) stock of odd relays for one which makes a good audible "clunk" when energised, Then it will seem as if I have a "proper" contactor of the type the lathe would have had when new!

I accept what Michael has said about 240v being safe if carefully handled but as I am more of an "Amateur Electrician" I will use a LV relay and fit an appropriate LV supply, I can always tap into the LV supply for additional lamps etc so it won't be wasted.

Thanks again. Rod

John

Thanks for your prompt and constructive reply. I had thought of using a latching relay circuit but was trying to avoid the extra complication of the necessary LV power supply.

The commercial pendant control units seem to avoid the need for relay or power supply and was hoping someone knew how it could be done for my VFD.

Once again, thanks

Rod

Hi all,

I am guessing that this thread will have attracted the attention of all those who have VFDs. While you are are reading can I ask for help.

I have a "Eurotherm 601" VFD which works well and is connected up using the simple "Control Wiring" circuit on page 4-3 of the "Electrical Installation" section of the Product Manual. This circuit has a simple on/off switch connected across terminals 6 and 7 of the VFD to give stop and start control.

BUT I would like to be able to connect the thing up using a momentary "on" push button swich for Start and a momentary "break" switch for Stop, like the pendant controls available from some of our suppliers. Anyone got one of these VFDs and know how to connect for this?

Useful information in the link but I wonder if it was written mostly for large industrial installations, certainly I have no rigid steel conduit.

Thanks

Rod

I understand the word "exactly" is used in scientific and technical calculations to advise or remind readers that the unit being used is defined as that number in another set of units.

For example, the inch used to be defined by its relationship to the Imperial Standard Yard ( A metal bar kept in a bank vault somewhere.) and it was approximately equal to 2.54 cm But the exact conversion factor was a long decimal which changed a small amount from time to time for esoteric reasons.

Now the inch is defined as 25.4 mm (exactly) and the Standard Yard has been relegated to history. Which is a pity in some ways but at least it simplifies calculations and brings certainty. It's probably academic as far as we are concerned but some scientific calculations and measurments are done to levels of accuracy and numbers of significant figures which are far beyond anything needed in other fields.

Bill

I have not tried to make a nut but I think it would work well.. Unlike silicone, epoxy or Sugru etc, Polymorph does not bond very much to other materials. It just sets in a block in whatever shape it has been formed into. It is not a glue. One would have to form the "nut" inside a housing which had an internal shape or keyway to prevent the Polymorph moving within the housing. A release agent like a thin oil, graphite or even talc might be a good precaution on the screw, just in case. One of the beauties of this stuff is that one can experiment, and reuse the material if it does not work in a particular application. It should be a lot easier than trying to squeeze a nut out of nylon etc.

Regards

Rod

Hi all

Just a suggestion really.

Look up PolyMorph or MultiMorph on the web or on Amazon. Both names are used by the same firm for a thermoplastic supplied in pellet form which softens in hot water. Once soft it can be worked like modelling clay to form moldings which set in 10 minutes to a hardness similar to nylon. It's quick and clean and handy for making replacements for broken plastic parts etc. It is also reusable, if your first attempt is not good then put it back in the hot water and try again. The usual colour is white but some packs contain dye packets to colour the plastic and the set plastic can be painted. It is also useful for making "soft" packing for holding awkward shapes in the vice or chuck for machining, and if it's a one off job then the packing can be re-softened and re-used. The sellers suggest it can be used for making jewellery, but I have not tried that! Usual disclaimer.

Regards

Rod

Hi All

I have fitted one of the LED batten lamps from Screwfix over my lathe and the result has been a revelation. One can see every particle of swarf, every drop of coolant, any scratches and marks on the work and every graduation on the dials. It's like what I imagine it is like to work under an operating theatre lamp, is "forensic" the right word? My particular lamp is 4 foot long and consumes 41 watts, the light is a bright cold, shadowless white, the lamp starts instantly, and is fully bright immediately. I used to have a 500 watt "security" floodlamp over the lathe but this LED lamp is much better, though not as warm in the winter!

It was about £50.00 but it was money well spent. It's supposed to last a long time, so I am hoping it's a fit and forget.

Rod

Jason

Brilliant!

Thanks

Rod

Hi Guys

Anyone remember a short series of articles in one of "Our" magazines, under the above title, in which the author described making workshop items, such as a tool and cutter grinder, out of household items such as short lengths of plank and door hinges etc?

Anyone got the reference for these articles? I have access to back numbers of the magazines.

Thanks

Rod