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Member postings for Mark Rand

Here is a list of all the postings Mark Rand has made in our forums. Click on a thread name to jump to the thread.

Thread: The effect of lubrication on reaming tolerance
19/03/2017 21:27:01

Glow cut as in cutting/tapping oil. Not CI fuel. smiley

Thread: What Did You Do Today (2017)
15/03/2017 19:49:07

There was a day when the trainers were expected to know how to do running repairs on the machine tools and to educate the apprentices in the process. crying

Thread: Freecutting v Tempered EN16 & EN8 - How do they differ?
15/03/2017 19:41:04

T is the heat treat condition rather than a chemical variation. Usually about 30HRC, which actually makes the metal slightly nicer to machine:- less 'grabby', compared with the straight EN8 or EN16. It's also a reasonable state for components that don't suffer extreme stress. Nuts come to mind.

The M versions have extra sulphur to make them easier to machine, but they won't be hardened as they come. Doesn't matter for cams if you're going to harden them after machining.

Thread: Next MEX 2018
11/03/2017 20:14:27

Bristol should be within range, depending on how far into the moors you are!

Edited By Mark Rand on 11/03/2017 20:15:32

Edited By Mark Rand on 11/03/2017 20:15:46

Thread: Milling - What am I doing wrong
04/03/2017 00:37:12
Posted by petro1head on 03/03/2017 18:29:51:

I was take a .5mm cut. (when everthing is working fine could I take a deaper cut?

 

A good rule of thumb to work with is the full diameter of the cutter in width and half the diametar in depth or half the diameter of the cutter in width and the full diameter in depth. That'll give a reasonable load for an HSS cutter. or pro-rata!

In general, try to use as much depth as possible, since that's using more of the cutting edges on the flutes. the more use you get out of the sides of the cutter, the more metal you can remove with it before the corners go blunt and you have to get a new one.

Carbide can be worked harder.

Edited By Mark Rand on 04/03/2017 00:42:28

Thread: 13x13x4" square pressure tank
20/02/2017 21:31:08

If you can build it to withstand 15 (long) tons without deflection of the 13x13" faces then you may be in the right ballpark.

Edited By Mark Rand on 20/02/2017 21:31:30

Thread: tool misuse/abuse
18/02/2017 23:12:35

And here our scientists are developing the new "sintered metal flavour" OXO cubes. wink

Thread: MEW 252
18/02/2017 20:17:12

Doesn't it spoil the joke to have the wrong number on the March edition, instead of the following month's?

Edited By Mark Rand on 18/02/2017 20:17:43

Thread: Myford ML7 spindle internal taper/counterbore?
16/02/2017 23:33:54

I guess this counts as an 'ex-college machine, with little use' crying 2

Thread: Workshops
16/02/2017 12:38:21
Posted by Neil Wyatt on 16/02/2017 12:09:43:

Enough! Body piercing is NOT a workshop technique!

devil

Neil

There have been times when my local A&E department would beg to differ.crying

Thread: Gear cutting with a shaper?
14/02/2017 21:08:24
Posted by Michael Gilligan on 14/02/2017 10:30:30:

... Which shows positive location of the bands, rather than reliance upon [for want of a better term] a 'capstan wrap'.

I think this design-detail might be worth incorporating in the Shaper attachment.

MichaelG.

Sorry, that was thought to be so obvious that it didn't need mentioning cheeky.

13/02/2017 20:18:32

Yes:- the diameter of the pulley or drum must be the gear's pitch circle diameter minus the thickness of the wire. This puts the neutral axis of the wire at exactly the pitch circle diameter. Any other diameter will cause the gap between the teeth to be too wide, as the gear will rotate too fast or too slowly and the resulting form will also not be a true involute.

The wire should also run exactly straight and parallel to the motion of the table, otherwise it'll either get loose or too tight as the table traverses.

On mine, since I used 2 thou shim stock instead of wire, the drum was 2 thou smaller then the PCD of the pinions.

Edited By Mark Rand on 13/02/2017 20:19:14

Thread: What Did You Do Today (2017)
12/02/2017 19:00:24
Posted by Neil Wyatt on 12/02/2017 12:13:40:

Thanks Muzzer,

Its solid beech I wanted, to make a hinged frame to carry wheels for my mobile display. The timber merchant I selected only does things by the lorry load.

Inspired by a soft-toy labrador push-along...

I can haul over to a timber merchant in Tamworth or Stafford tomorrow and get some.

Neil

Are you within range of Great Barr Sawmills? They're simple, reasonably priced and helpful. I've started using them after the two decent timber merchants in Rugby turned themselves into low grade builders merchants.

Thread: Gear cutting with a shaper?
11/02/2017 20:34:15

I cut two 14 tooth gears for my Hardinge HLV rebuild using the 'Base Circle' technique in Michael's link. One was 14.5° PA full form and the other was 20°PA stub form. Just needed two different ACME type tools for the correct PA. I used 2 thou shim stock instead of the wire in the link. Other than that, the setup was very similar.

 

A not very good video is here:- **LINK**

I had used involute cutters for the other nine gears in the apron gearbox, but these two could not be done that way because there wasn't enough clearance for the cutter on one and the cutters didn't have the correct PA on the other. Hence the shaper job.

 

Once I'd built the jig to index and rotate the blank as the table moved sideways the work was simple, if somewhat monotonous.

Edited By Mark Rand on 11/02/2017 20:37:55

Edited By Mark Rand on 11/02/2017 20:39:27

Thread: Inverter vfd's do's and dont's
05/02/2017 11:09:41

It should be noted that the Lenze guidelines apply to the lenze VFDs, not necessarily everyone else's products. My large Danfoss VFD specifically states that there is no restriction on switching between VFD and load. Which is good, since I use it to power three separate machines with six motors between them.

Thread: Stuart Beam ENgine
31/01/2017 13:26:20

Cast iron has been used for steam engine cylinders and pistons for four centuries without too many problems. A bit of oil does wonders. smiley

Thread: Todays update from Bodgers Lodge
29/01/2017 20:06:41

Apologies for more thread drift, but it might be relevant to Sir John, Graeme and others. I've also got one of the same welders, albeit with a different (Local Tool Sales) badge.

Be careful if you happen to do a bit of DCEP welding with some 6010 rod or similar. On mine, the return/positive connection is/was grounded to the case. If your welding bench happens to be earthed, as it should be, an escape of magic smoke can occur when one turns the welder on and the welder tries reconcile a positive earthed case with a negative earthed bench.

Repair under guarantee took a few weeks with mine, but was not particularly stressful. Didn't damage the output inverter but the control board got fried in collateral damage.

Thread: Tig vs Silver Soldered boilers ?
29/01/2017 12:23:21

A sort of compromise question...

What about TIG brazing of boilers instead of gas torch silver soldering?

Thread: ME 4552 page 149
17/01/2017 23:42:43
Posted by Tim Stevens on 17/01/2017 23:14:41:I am obliged to Duncan for agreeing that the method was strange, but I make no sense of the comment by Neil that he uses 'Tubal Cain's method' without any clue as to where one might learn more about what this method was (or which Tubal Cain he meant).

Cheers, Tim

There was only one:- Tom Walshaw. Any later incarnation is an imitation.

Thread: Need to get a Welder!
15/01/2017 21:47:05
Posted by Jonathan Persson on 15/01/2017 21:26:57:

MIG welders allow you to do fairly good welds without as much training and practice as TIG or Stick welder

 

But without the required skill and experience, they can produce welds that look nice but have no strength at all due to lousy penetration. This may not be a problem until the day you weld something that you expect to take some load. I speak from bitter experience on this problem.

 

Edited By Mark Rand on 15/01/2017 21:48:12

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