Member postings for Peter Cook 6

I think I used 600 grit to start, then finished with 1200. I think I smoothed of the surface to get rid of the print lines before filling with paint, then after the paint went hard repeated the smoothing.

Graphics were more than adequate for my purposes, but nothing like exhibition standard.

Edited By Peter Cook 6 on 01/06/2023 12:13:21

I made a switch panel in the same way. After printing I filled the trenches with enamel paint. After the paint dried hard (48 hours) I used fine wet and dry to sand the top surface smooth. That removed the fine lines of the printing, and any paint that had spread.

Enamel paints go harder than acrylics, so give a better edge.

Edited By Peter Cook 6 on 30/05/2023 20:26:59

The one I use is at Free Beam Calculator | ClearCalcs

it needs - besides the obvious (length, position of supports, distribution of load etc)

Young's Modulus of the material - steel is 200,000 Ali 68,000 others are on the web.

Area of Cross Section of the beam - basic geometry or for more complex shapes the calculator below will give you the area.

Second Moment of Area (Moment of Inertia) calculator for most shapes at Free Moment of Inertia & Centroid Calculator | SkyCiv

Hope this helps.

Edited By Peter Cook 6 on 30/05/2023 12:04:38

There are several free beam calculators on the internet that will let you do deflection calculations. You can test out various materials and cross sections without risking your box section - or the bodies you hang from it!

On most (all?) Mercedes keyless systems a double push on the lock button turns the key off, so that it doesn't broadcast. You do need to press a button on the fob to reactivate it the next time you use the car, but it does prevent these attacks - also reduces the chances of the fob battery going flat!

When choosing, don't forget you will also need to buy tooling and "other stuff". That quickly gets expensive.

I would agree with most of what has been said above. I bought an SX1LP from ARC a couple of years ago, and am not at all disappointed, but then most of the work I do is clock scale in brass and aluminium and the SX1LP is ideal for that. Occasionally when milling something a bit bigger in steel it can feel frustrating having to take small cuts. But the next job ( e.g. putting an 0.75mm hole in the edge of an hour pipe) it's high speed and delicacy of feel is a saving grace.

I think the function you want is in Construct/Curve which has four choices Project - Isect- Silhou - ISO

Although have never used them, they seem to do what you want.

I do use Boolean for most add/subtract operations - but then I am still learning.

One other thing to be aware of, there are available ( for free via the forum) a lot of add-in functions that can be used in MOI. I use the one that creates threaded fasteners, and one that creates gear wheels (specify Mod & Tooth count). There are many others.

Edited By Peter Cook 6 on 19/05/2023 17:52:08

As I don't use the other CAD systems, for the reasons explained above, I am not 100% sure what you mean by "doing assemblies". That model is put together part by part - in almost exactly the way I would do it in the workshop.

Each part is created individually (in my case mostly by hiding the rest of the model while I do so), then connecting or associated parts are unhidden using the browser and the bits put together, then the rest of the model is unhidden. That model was actually created by designing the three trains as separate MOI models, then combining them into a single one.

It doesn't do animations, although I often use stepwise rotation of parts to ensure things don't interfere with each other.

As Jason says there is no problem modelling parts and assembling them in MOI, but which tool you choose depends both on what you want to do, AND which ones you find easiest.

I use MOI simply because I "get on" with its underlying design paradigm. Never having ben trained in engineering design or technical drawing I struggle to get my head around the paradigm that underlies the majority of the 3D CAD programs.

This is an MOI model of a clock I plan to make. All the parts can be separated from the whole, and drawings or diagrams created to take across t the workshop. Drawing each part in MOI makes me think about the design choices, while putting them together in MOI makes sure that they fit together.

One approach is not better than the other - they are just different, and at the limits are capable of different things. I will never reach the limits, so I stay in the middle with the tools that I find easiest to use.

Probably some very useful ground steel rods inside!

Math

Using a beam calculator (Free Beam Calculator | ClearCalcs with moments of inertia from Second Moment of Area Calculator (amesweb.info))

A 1200mm length of scaffolding pole (48.3mm) rigidly supported at each end and subject to a 750kg ( 3/4 tonne) load in the centre is going to flex downwards about 10mm. The same diameter solid bar would flex about 5mm.

A 100mm diameter bar would only flex about 0.2mm. However I'm not at all sure how you would get a 84kg bar up there in the first place!

Depends how you define comfortably!

Edited By Peter Cook 6 on 16/05/2023 19:05:20

Section 10 of the 1971 Coinage Act makes doing this with UK coins illegal.

As others have said repeatedly, the fundamental problem is the power adapter.

You say

Motor:
DC 12v 1000rpm motor

• No-load current: 240 mA <------------ 2A adapter can supply this
• Stall current: 5.9 Amp <------------ This requirement is way beyond it.
• Stall torque: 7.5 kg-cm

Get a 6A or preferably 10A power supply and it should go.

The adapter you have is satisfactory for the No-load condition, but way too small for the stall current - which it will hit when starting up.

You will also need to check/adjust the shimming each time you re-sharpen the tool.

Nigel, Roger asked a new question.

As Jason says you need a 34 hole plate, but looking at the online manual for that dividing head, you don't have a plate with that number of holes.

Using the 17 hole ring on the A plate you could make a 34 hole plate, then use that to cut the gear. If it's for a one off and you have access to a 3D printer it is possible to print a plate with 34 holes which would probably be adequate.

Can you not get a bit creative with the tool holding? The spec on the mini lathe seems to imply a 70mm cross slide travel as standard so 105mm dia should be within its capabilities.

To face the 105 mm diameter, turn the tool post round and fit a left hand knife tool facing towards the work. the same setup should machine the outside, although you will be limited in the longitudinal travel by the toolpost fouling the end of the cylinder

Depending on the size of the tool, there is an interesting approach to using diamond wheels to hone small scale tools at Taig Lathe: Lathe Tool Sharpening Jig (toolingaround.ca)

If you are making bushings, the work hardening needs to be in the hole where the pivot goes to be of any use. So I think you will struggle to do that by hammering, even of a blank.

The normal way of work hardening the bearing surfaces of a clock bush is to finish off with a smoothing broach which burnishes the inner bearing surface.

Depending on size, I would have thought a scanner would be the best option. A0 scanning services seem to be fairly commonly available if you have a few. If you have a very large number you might consider investing in a scanner.

Bearing in mind the budget, could something like a garden micro drip watering system be adapted using a header tank. Plastic tubing and adjustable drip nozzles, starter kits of 20-30 nozzles and tubing seem to come in at <£20.