Member postings for Michael Cox 1

I have made something very similar. Yesterday I submitted a short article to Neil to consider for his short article edition.

Mike

I use the headstock Morse taper sometimes.

I make MT2 tooling for my mill. I usually make the taper in the lathe, holding the work in the chuck. I then remove the chuck and fit the taper , with an MT2 to MT3 adaptor in the headstock and then machine the business end of the tooling. This ensures concentricity of the tooling with the taper.

When gear cutting I mount the gear blank in the lathe headstock using an MT2 to MT3 adaptor and an MT2 to ER32 adaptor. I can then machine the blank to size with good concentricity to the taper. Once the blank is machined I can remove the taper from the headstock and transfer it to the MT2 tapered hole in the centre of my rotary table on the mill for cutting the teeth. After cutting the teeth it can be transferred back to the lathe for de-burring.

I also have an adjustable stock that fits into the headstock taper for making multiple parts all the same size.

Mike

Thanks for all the responses. They have provided some interesting things to follow up on.

Mike

Vic, would you care to elaborate why you think the tool is so bad.

Mike

I have just finished making an extended micrometer, see:

http://mikesworkshop.weebly.com/extended-micrometer.html

This is based on a design by mklotz.

It is fine "as is" for relative measurements but in order to make absolute measurement I need some standard precision blocks that are 25, 50 and 75 mm long to provide calibration standards.

I have some imperial 123 blocks that are certified to 0.0005" but what I really require is the metric equivalent of a 123 block i.e a 25 x 50 x 75 mm block. This would make a good calibration standard for the micrometer.

Do precision 25 x 50 x 75 mm block exist? If they do who supplies them?

Any ideas?

Mike

I have one of these nibblers:

http://www.rdgtools.co.uk/cgi-bin/sh000001.pl?WD=nibbler&PN=TWIN-HEAD-SHEETMETAL-NIBBLER-740%2ehtml#SID=241

This works well up to 1.5 mm thick steel. I have never tried on 2 mm. It is designed to attach to a portable power drill. It is quite difficult to control because the head can rotate with respect to the drill. I made a simple mod to fix the head to the drill, see:

http://mikesworkshop.weebly.com/nibbler.html

I also built a table mounting for the nibbler head, see:

http://mikesworkshop.weebly.com/a-nibbler-table.html

The nibble table gives very good control for precision operation on small pieces of steel sheet. Another benefit is the nibbles all stay in the same place and are not distributed throughout the workshop.

Mike

Hi Chris,

The ideal material would be carbon black but it is difficult to find in small quantities. I have some black powder that is used for powder coating steel articles. This is basically a mixture of carbon black with a thermoplastic. It is very fine particles (they float in air). If you want to try this to pigment the epoxy I can send you a small quantity by post. Send me a pm if you are interested.

Mike

Did you find that out the hard way?

I had no problem when using the 80 mm chuck on the lathe but when I updated to the 100 mm chuck and backplate I had this problem. The back plate is thick and drilled for both three and four jaw chucks so there is an imbalance due to the non symettric arrangment of holes. This led to vibration in the same speed range that you cite. At a later stage I upgraded my machine to a spindle with a 100 mm flange (as used on the Real Bull lathes) This eliminated the vibration.

Mike

A list of common etchant used for the metallographic examination of steel is given here:

http://www.asminternational.org/documents/10192/1756301/amp16006p042.pdf/f805348f-5422-4460-985f-36307cf4bbf7

I think what you really want is an etch that will reveals the grain boundaries and inclusions in the steel such as the nitric acid/ alcohol etch (nital).

Mike

I have always had good, fast service from Arc.

I ordered two drive belts for my minilathe from Arc recently along with a number of other items. When the order arrived the next day only one drive belt was present. I phoned Arc immediately and the second belt was sent and arrived the following day. No quibble, no fuss, just brilliant service.

11/10 from me as well.

Mike

Hi Andy,

If there is an open circuit across the original primary connection then I think you are correct in assuming the transformer is NBG.

Don't eat to much cow pie it might make you desperate!

Mike

Hi Andy,

No need to worry about the the different transformer it will work well in the same circuit but reduce the bulb to 40 watts.

I agree that the lamp should be shielded for safety. An old soup can with a hole in the bottom serves on my unit. I did not show it in the photo of the unit because I wanted to show the bulb.

Mike

Rod,

Where is the design for the hardness tester published.

Mike

Blackgates, http://www.blackgates.co.uk/tools___sundry_items.html, stock a case hardening compound that contains the same active ingredient as Kasenit. I bought some at Harrogate 3 years ago and it works well. I think the price was around £5 for a 500g tin.

I have also used pack carburising by putting the parts in a mixture of charcoal and sodium bicarbonate in a sealed box. This is then heated to bright red heat for an hour or so and the carburised items then domped into cold water.

Mike

I have often thought about trying to make a simple tool for thread forming. In essence it would be a little like a conventional scissor type knurling tool but with the rollers threaded at the required pitch. It would be used like a knurling tool but with the leadscrew engaged and change gears to suit the required pitch. Has anyone seen or made such a tool?

Mike

Hydrofluoric acid is very nasty stuff as has been pointed out here. It can be rendered safe fairly easily by first diluting it and then adding hydrated lime. This is available very cheaply from any builders merchant. The lime, calcium hydroxide, neutralises the acid and converts it to insoluble calcium fluoride. Because it is insoluble calcium fluoride is relatively safe in the environment. In fact, calcium fluoride is the form in which most fluorine is found in nature, The mineral form is fluorspar or blue john. It is an abundant mineral throughout the Pennine areas of northern England.

Although it is easy to make safe using this procedure I would not advocate it being done by inexperienced amateurs.

Sulphuric acid is very non volatile and fumes will not escape from a plastic or glass bottle. Nitric and hydrochloric acids are volatile and the will escape through plastic but not glass bottles. If the plastic bottles are normal clear/translucent polyethylene bottle then at room temperature they should be unattacked by the acids. However, sometimes they are supplied in white polyethylene containers and these tend to be slowly attacked by acids. Chalk is often used as a pigment in white bottles and as the acid fumes diffuse into the plastic they react with the chalk liberating carbon dioxide and this causes the bottle to become covered with small blisters. This will happen fastest with concentrated hydrochloric acid and much more slowly with sulphuric acid solutions.

Mike

Hi Brian,

For what it is worth this was my experience when I first bought my mini- lathe:

http://mikesworkshop.weebly.com/initial-experiences.html

I would recommend that you start with a set of HSS tools like the Arc set. You should think about buying a bench grinder because they will need regrinding sooner or later. A cheap 150 mm bench grinder is fine but you will probably need to make a new grinding rest in order to grind consistent angles. My version is shown here:

http://mikesworkshop.weebly.com/grinding-rest.html

Mike

Clickable links added

Edited By John Stevenson on 18/08/2015 15:33:28

Soaps are salts of carboxylic acids such as stearic acid (stearine). If it is the sodium salt it is the familiar hard soap used for hand washing and if it is the potassium salt then it is soft soap which is used as an insecticide and mould release agent. Chemically they behave very similarly and both work well at preventing scale formation.

The liquid hand wash that is sold in bottles with a pump top are not usually soap but sodium lauryl sulphate which is basically the same as many washing up liquids and shampoos. It also contains other compounds such as thickening agents to give it body. When heated to red heat the sodium lauryl sulphate will be reduced to sodium sulphide which may introduce sulphur into the surface of the steel. This could cause cracking and render the steel liable to corrosion afterwards.

I have, in the past, successfully used both soft soap and hard soap for scale prevention but nowadays I use common household soap because it is much more readily available. With a knife it is easy to shave the block into slivers that can then be crushed easily to a powder. Heat the metal a little and dip it in the powder . The soap will melt and stick to the surface. Then heat the metal to high temperature for heat treating. Much of the soap drips off as the metal is heated but sufficient remains to prevent scaling. An even better alternative is to mix the powdered soap with powdered chalk (roughly 50:50). This mix does not drip off of the hot metal and remains as a crust on the surface.

Mike