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Member postings for Mark C

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

Thread: Coupled Wheel Geometry (Fusion 360)
31/01/2017 20:52:21

Murray, That is what I was getting at. You could always do a full blown dynamic simulation but cost of equipment (not just the software) would be a serious investment and the skill would be past my pay grade I would think.

I take it then that fusion does not come with dynamic simulation?

Mark

31/01/2017 20:43:16

Murray, I can also confirm that when you are about a mile and a half from the gents (a wind sheltered wall would not cut it) and the only vehicle to get you back is a Scania prime mover with an air leak, getting the breaks off takes an eternity.... on the plus side, they do get a move on with not trailer!

Mark

31/01/2017 20:22:20

Dave, That sounds suspiciously close to a dynamic motion analysis - perhaps Murray can enlighten if this is available in fusion?

If it is not, you can probably get all the information you need from section properties dialogues to allow hand calculations (perhaps in excel, given your comments about not wanting do the maths) to be made.

Mark

31/01/2017 20:15:01

At least on a tractor unit it would have spring brakes so it would fail safe but I expect there might be a big kiss pressed on the windscreen at head height!

Mark

31/01/2017 18:39:25

Murray,

You certainly can model "dynamic" looking springs in Solidworks (IE. they appear to compress/expand as the attached assembly parts move) and you can use dynamic mates and other advanced features to simulate the spring action/force. None of this is under the heading "basic modelling"....

As for the wheel link; the same happens with Solidworks and is down to the uncertainty of the possible options at the point they invert (as mentioned by others). In Solidworks we would probably add a parallel mate relation with the frame part or the horizontal plane (or create some reference sketch geometry if you wanted to waste time and be a smart arse.

Mark

real wheels also have friction applied to the contact with the rail and the axles are rigid fixed points, all of which will help to ensure they generally both turn together.

Edited By Mark C on 31/01/2017 18:41:12

Thread: Why is the pilot diameter of a counterbore so large?
30/01/2017 20:55:25

"which is more likely to be cast than formed with precision" Afraid not, It is most likely to be forged on a cap head and is going to be reasonably accurate in a decent quality item.

Mark

30/01/2017 20:49:16

Oh no, geometric tolerance..... run away!

Mark

30/01/2017 20:40:35

I don't see why 10mm is big - it is only 1.5 mm bigger (0.75mm a side) than the head (8.5mm). They look "right" to me but perhaps I am not very demanding?

Mark

30/01/2017 19:44:25

To qualify what has been mentioned about standard sizes; Taking the M5 (to suit a cap head in the form BS EN ISO 4762 or DIN 912, which covers most of the screw/bolts you will get hold of in the uk - far eastern will probably not conform) the standard is three classes of fit, loose, normal and close.

In numbers they are all 10mm diameter counter bores taken to 5.4mm deep but the clearance diameter for the screw can be 5.3 close, 5.5 normal and 5.8 loose. When detailing them on a drawing you can add further information to tie down the small under head and counter bore chamfer (or radius if you so wish).

Mark

Thread: What Did You Do Today (2017)
28/01/2017 22:08:05

And if you still can't get in with the bend, how about cutting the wall to take the bend into the outer leaf (assuming the wall is cavity) and making good afterwards. As Michael pointed out, a rodding access would be good (possibly required by BC) on that bend.

Mark

28/01/2017 20:00:50

Murray, you should have got a wall hung bog, they have all sorts of options for the soil pipe and look really good when installed. Additional to the cosmetic appearance, they are hygienic in as much as you can mop under them easily after less careful visitors...

I am guessing you already know, but you can get swan neck connectors with a very tight (reversed) outlet?

Mark

Thread: Boxford lathe gurus...
28/01/2017 12:17:27

Whoever machined the front face of the head casting for the locking pin must have some original paint by the look of it. If it was all painted at the same time, it would be a suggestion it was done in the factory I would guess? I might point out none of the machines I have owned have had that flat machined and I have had a number of different types and vintage of Boxford.

Mark

Thread: Corner joints in Plywood
28/01/2017 12:08:02

Jason,

Out of interest (and I don't know how technical your knowledge of these glues is), are all PU "gorilla" type glues structural (D4)? I know that all PVA adhesives are not suitable for permanent construction joints. I think it may be the case that PU is always water proof as opposed to PVA which generally does not like to be wet for any length of time (it came as a bit of a revelation to discover that I should use acrylic sealer under tiles rather than PVA).

Mark

Thread: Plans for a small bore spiral pipe bender
27/01/2017 21:38:58

Oh OK, slap my wrist...

Yes, you are correct, the question put the word at the front of my mind as I was thinking of spiral tubes - the sort made from a strip and clinched/welded into a tube as you often see in air conditioning and ducting systems

Mark

Thread: Corner joints in Plywood
27/01/2017 21:35:28

Also, the ply was probably made using a relative of gorilla... perhaps assembled by one as well?

Mark

27/01/2017 21:33:24

For reference, the Gorilla glue is the same sort of stuff as the D4 adhesives I think? They are a thick brown liquid with a consistency about the same as not very runny honey if that makes sense. As Gordon W mentioned, don't open it and leave it sitting about for a couple of months 'cos it will no longer be runny!

It sets really quickly - the Everbuild stuff I get takes about 3-5 min's and once the foaming has finished (gone yellow) it is more or less set. It is fully set within an hour or so and I tried pulling two rough bits of building timber (C16) apart as a test - it simply ripped the face of the wood after a half hour setting time. As it is viscous it allows you some scope to manoeuvre the joint on assembly but don't let it get on anything you don't want stuck... It has the same affinity for fingers as super glue but with a little less setting speed (once it's on it is going to have to wear off)

Mark

Thread: Plans for a small bore spiral pipe bender
27/01/2017 20:18:28

Yes, I think if I had just one or two to coil I might turn a mandrel and make a guide for use on the lathe using very low back gear or by hand. This obviously prevents you from having a long tail at the start end...

Mark

27/01/2017 19:54:27

Is that spiral as in "spiral pipe" or "spiral bend" like a coil spring?

Mark

Thread: High speed induction motors
27/01/2017 19:33:29

A slightly different approach to getting a high speed spindle (spurred on by the idea of putting a speed increaser on and thinking about alternative "compact" power and coming up with air turbines to run in the spindle) it turns out you can buy high speed air spindles. I did not spend much time looking but try searching "air turbine tools - high speed spindle". You should find a fair few ideas with commercial products reaching at least 80k rpm. depending on cutter size, perhaps dental equipment? I have never seen one in use - most of what I do is at the other end of the scale

Mark

Thread: Todays update from Bodgers Lodge
26/01/2017 23:37:12

John, mine is DC only and is multi mode (Mig/Stick/TIG) and the last time I used it in TIG mode I forgot to swap the polarity on the earth - resulted in a large flash and a nice tungsten/copper flash coating over the job with some vitrified material that was once a gas shield!

Mark

Edited By Mark C on 26/01/2017 23:37:24

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