Member postings for Mark Rand

The cutting mats dissolve in cellulose thinners as well.

Edited By Mark Rand on 10/12/2017 13:15:13

I have an Ingersol Rand float operated drain valve. It isn't connected to the compressor yet, but that's because the permanent compressor plumbing is one of next year's projects.

£15 on flea bay .

Cut using as much of the length of the endmill as you can, rather than taking shallow cuts. Lots of shallow cuts wear out the edges on the end/corners of the endmill long before you've removed much metal.

Also, assume that you can remove 1 cubic inch of steel per minute for each horsepower that the motor's got (other unit systems are available ). Adjust your width of cut to take as much of the motor's power as you can, subject to belt slip etc.

As I noted above, you do get ferrous citrate produced with steel and citric acid. It's almost insoluble, so you get a thick layer of precipitate. You wouldn't get that with the other posited reaction.

PS:- I see nothing novel in that patent application. I hope it was denied...

Edited By Mark Rand on 03/12/2017 21:01:40

You very definitely do get ferrous citrate produced! it's quite surprising when you've got the mixture simmering on the hob and all of a sudden a layer of white powder precipitates on the bottom of the casserole dish (cleaning up a days worth of vertical lap TIG welding practice pieces, so I could weld the other sides up on the following week's session )

There was no remaining FeO on the pieces!

Edited By Mark Rand on 02/12/2017 01:39:34

Trouble is that the magnetite tends to get blown off the iron by the hydrogen that's forming underneeth it (or by the cloth that the owner uses to dry the parts with). Major thing is that it won't remove any metal, which the acids certainly do. In the case of reamers, magnetite isn't all that good a cutting tool material and in the case of nice micron comarators it ain't that pretty either .

Phosphoric acid, boiling citric acid and Vinegar/salt solution will all remove metal (I've got a stainless steel teaspoon that stands witness to that).

Evaporust, EDTA or molasses solution work as chelating agents and generally do not remove the base metal (avoid any air/liquid boundary or you'll get corrosion at that point)

Electrolysis will not remove the base metal assuming you've got the right polarity.

I've used all these methods and tend towards electrolysis or molasses these days except for pickling of rough hot rolled steel, where I use the acids.

Bear in mind that none of the methods will restore corroded metal, so you'll be left with what ever pitting/loss of shiny surface that the corrosion caused. A bit of washing up liquid or similar in any of the solutions can help with general cleaning...

If you use EBay, insulating firebricks and ceramic blanket are readily available. If you don't then pottery suppliers such as Bath Potters have the materials.

No connections other than as a customer in both methods!

I find the calibrated handwheel in my Hardinge HLV (600 thou/rev) to be very handy.

Interesting snippet:s-

Hardinge's 22DP gears and racks (and the teeth on my Beaver mill quill feed) give almost exactly 7 teeth per inch.

Myford's 20DP gears and racks give almost exactly 4mm/tooth

Might be simpler with a metric lathe and Module gears, but those two rations can be very useful.

Surgical spirit definitely does leave a residue. It's industrial spirit mixed with 2.5% castor oil. Industrial spirit is the one you'd want, That's ethanol with 5% methanol.

Regards

Mark 52 years a diabetic, injecting insulin

I thought we had enough problems when PC makers started using 9 or even 5 Volts, instead of the 20 Volts that was expected by older devices... Seem to recall that there were some Maxim integrated circuits that could deal with the voltage shift.

RS232 was always single ended, but ISTR that RS485 was differential voltage levels.

If you're up to soldering a resistor and a three terminal device to the pins of a Rasberry Pi, then copying a few lines of code, you can do this sort of thing:-

Edited By Mark Rand on 25/11/2017 15:09:33

It should be noted that you can only get more than rated power at higher speeds if you can also supply more than rated voltage to the motor. The maximum current which gives the torque, is pretty well fixed. But in order to drive that current through the motor at more than rated frequency (giving increased power) the VFD needs to provide higher than rated voltage.

Don't worry about the electricity cost of running the lathe at full power. You are extremely unlikely to be doing that for more than a tiny fraction of the time unless it's a bar fed CNC machine doing production work! Using a common approximation, 5hp is equivalent to removing 5 cubic inches of steel per minute. That's quite a lot of swarf to dodge. On the other hand, a more powerful lathe will almost always be more useful just because you can take a decent cut with it, or run carbide tooling at a sensibly high speed.

Does the slot create a reservoir for bubble mixture to allow larger bubbles to be blown? Expiring minds want to know!

I got the bridge crane in the shed working to the point that I could start moving all the stuff back to where it was before i moved it to erect the columns and crane rail:-

Edited By Mark Rand on 24/11/2017 19:11:51

Planted a couple of bags full of daffodils in the garden today. Instead of forking over the ground first, I just pushed holes into our clay soil with a trowel, I wasn't wearing gloves either.

Be sure to use all appropriate Personal Protective Equipment and labour saving tools when doing stuff...

Allan Smethurst deserved better .

Lived in Lynn (Gaywood and South Wootton) as a child.

Rather than having the stand level, it's better to arrange it so it slopes a little bit towards the drain that's at the tailstock end of the tray. that way you don't end up with puddles of oil in the tray (total loss lubrication, way oil and cutting oil). If you want the lathe bed level, adjust the riser blocks to counter the stand's tilt.

I picked up an 8" Abwood or J&S style milling vice from work that had been one of four that occasionally got used on a little Lumsden grinder. I thought it might be handy on the 48"x10" Beaver milling machine.

Note to the wise:- an 8" milling vice will NOT fit on a Bridgeport/Beaver sized milling machine! Since then, I picked up a couple of 6" Kurt copies and they are perfectly matched to the mill, but the big one keeps sitting there and taking up floor space.

Took me 4 years to rebuild a Hardinge HLV (no -H) lathe. Also took 4 years to rebuild a Beaver milling machine. I'm hoping the surface grinder will go a lot quicker because there's only a thou or so to scrape off the ways instead of the 10-20 thou on the other machines. But before that, I've got to re-lap the surface table so it's accurate enough to measure the surface grinder parts.

Making things? Never done any of that...