Member postings for Russell Eberhardt

I have this model of inverter on my mill and can confirm that you need to set the input voltage range to 5V. A 1k pot is just fine. If you are going to go up to 120 Hz make sure that your headstock bearings are OK for the top speed.

Russell

As John said, it is not easy.

Brass consists of an alloy of copper and zinc sometimes with a bit of lead to make machining easier.

Bronze (which includes gun metal) is primarily an alloy of copper and tin but usually with some zinc and other metals added.

One test John hasn't mentioned is to put a drop of hydrochloric acid on it and look at the colour change. Brass will go pink. Bronze will still change colour depending on the amount of zinc present but will be paler.

Short of a full chemical analysis if you have a critical application it is safest to buy known new material.

Russell.

It depends what you are going to do with the motor in reverse. I only use reverse when screw cutting metric threads on an imperial lathe to go back to the start without disengaging. I wouldn't try cutting in reverse.

Russell.

... and some stainless steel will develop rust spots. See some kitchen knives that have been in the dishwasher.

Russell;

If distortion is a problem you could always try clamping it up with solder paste in the joints and heating it gently in a domestic oven. The tin/lead solder melts at 183 °C so is well within the range of the oven. Solder paste is expensive but you'll end up using much less. If you set the oven to about 220 °C the flux won't burn and will wash off easily.

Best to try it when the boss is out shopping though!

Russell.

As Andrew has pointed out they are half round drills. They are number drills size 18 and 29 hence the marking. HS would mean HSS steel and US should be obvious.

Russell

You should be able to get hold of sulphuric acid at a builer's merchant, sold as drain cleaner. Some drain cleaners are however caustic soda so read the label. Dilute it to about 5% (up to 10% in cold weather) but remember to always add the acid to the water NEVER the other way round.

Russell.

Edited By russell eberhardt on 13/03/2012 20:52:54

For W.W. form threads I always set the top slide to 25 deg. as recommended by Geo. Thomas. This makes the trailing edge of the tool take a fine skim and results in a smoother thread. It also makes the calculation of the feed depth easier!

Capnahab, if you want a reference book with a good treatment of screwcutting I can recommend Geo. Thomas "The Model Engineers Workshop Manual".

Russell.

That's because it's just washing soda sold at a rather inflated price. It won't remove oxides. I just use caustic soda to increase the ph of my pool.

Russell.

Haven't come across this but I wouldn't use hydrochloric acid as it dissolves copper. I use dilute (5%) sulphuric acid which wll dissolve the flux and the oxides but not the metal. Citric acid is often recommended as it's safer but takes a bit longer.

Be sure to take the appropriate safety precautions.

Russell.

This can also happen if you overcharge NiCad batteries. Don't ask how I know!

Russell.

It doesn't matter whether I store them charged or not. When I come to use them the damn things are always flat!

Russell.

Tried that but it seems to promote rust.

Russell.

You might try contacting these guys: http://cimaf.es/FCD_index.htm

Russell.

Lining the screws up was always done on high quality small boats. It was also done on guns, the purpose being safety - you could see at a glance if a screw was working loose.

Russell.

Edited By russell eberhardt on 04/03/2012 10:09:39

Yes and no. Torque depends on the angle between the present position and the commanded new position according to a sine function. Thus for example if you are 1/8 microstepping and wish to move one microstep the torque will be reduced to 20% of holding torque. However if you wish to move say 4 microsteps at once the torque available will be 70% of holding torque and if you wish to move 8 microsteps the full holding torque will be available. Remember the motor will only produce torque as a result of a position error.

Russell.

Checking a bit further it would appear that the graph given on the Engineers toolbox site is wrong. The graph given on this site would seem to verify Neil's figures: http://encyclopedia.airliquide.com/Encyclopedia.asp?GasID=53

Russell.

If you want an adequate safety margin you will have to consider the maximum temperature the cylinder is likely to reach. The gas pressure varias considerably with temperature. See: http://www.engineeringtoolbox.com/propane-vapor-pressure-d_1020.html

Prsonally I would test to double the maximum pressure.

If it is only for your own use I don't think there is any legal requirement to comply with EU Directives or Standards.

Russell.

Not sure if it is T section crown stays per se or the particular design used on the Simplex but I was told a few years back that they are not accepted. My point though is that if you want to have it tested and certified in Germany you have to comply with the German regs (whatever they are). If you want it tested and certified in the UK you have to comply with UK regs (and the inspector's interpretation).

Russell.

They were never here!

What is becoming more important is to make sure that web pages work well on the various portable devices, iPhone, Android, Symbian etc.  I must say this site works pretty well Keith.

Russell.

Edited By russell eberhardt on 25/02/2012 14:58:30