Member postings for Nick Wheeler

I've never seen, let alone used, an oil-can or grease gun that didn't have at least a smear of its contents all over it.

All the good ones do better is force more of the lubricant into wherever you've aimed it.

Nobody has claimed that 3D the only way to draw something.

What we have been repeating is that you expect your program to extract a 2D technical drawing into a solid, but they don't work that way. All that means is an adjustment in your thinking is needed. Making up your own exercises to try and force your thinking on a different approach is further adding to your frustration. Which, again, we've been repeating.

Another reason for creating holes using a function and not sketches is that you rarely want one. So patterning one feature, that created a custom countersunk, threaded hole with a drill point bottom is much easier than doing that when you've performed several operations to make it. And you can easily change the thread size on all of them when you discover that the original breaks out in an unexpected location.

Fusion doesn't differentiate between cut and additive extrudes until you've selected the profile. Then it makes an intelligent guess at what you want; one in a blank space is almost certainly going to be additive but could be a new body or component, so you have the option to select what you want. It won't allow you to choose cut if there's nothing to cut. One near or into another solid could be joined to it, cut into it, or not affect it at all. One inside an existing solid will be suggested as a cut, because that's most likely.

Extrudes can be a specific distance, or to an existing feature of some sort. Referencing relevant features(holes, centre lines, planes, axes, edges, faces etc) is best practice. You have the option to cut through all and if it's a through hole that's the one you want as it will update if you change any of the dimensions.

I can't imagine creating a simple cylinder just to subtract it from another another solid that was created from a sketch; adding a concentric circle to that sketch saves a lot of extra work, and is easier to understand when you look at your efforts six months later.

That leads me to another important point: name all this stuff. It's much easier to check 'main bearing extrude' than extrude22, or 'cambelt cover' than component37

They look good.

A friend had the logo for his kitcar project 3D printed, and after painting them clear coated for a sort of DIY enamel badge look.

I'd use symmetry for the crosshead, but in one original sketch, and the extrudes:

Draw some rectangles and construction lines:

add several colinear constraints for most of the profile:

Draw 3 more single lines, then make the angles ones equal with another constraint:

Move everything about for the proportions - this is where you'd add dimensions - and the circle I forgot

Extrude most of the profiles symmetrically:

Extrude two more profiles symmetrically as a cut:

Mirror the resulting body around its own open face, ensuring that join is selected:

Finally, revolve the last unused rectangle around the construction for the hollow spigot:

That's probably as complicated a sketch as you'd want, but simplifying it would need two more for the other features. The pin would be created in place, using projected geometry from the hole it fits in.

Depending on how you model it, a T-nut is only two or three basic shapes. But it's useful as an exercise because you know what it ought to look like and understand what each shape does. That also explains why these two approaches are both better for different reasons:

Each identical solid is created from a simple sketch using two operations and the thread added by a third. The bottom is good for a discreet part; the top makes more sense when it's a part of an assembly

In order:

DAG Brown's book is hugely out of date for 2D CAD, and largely irrelevant for 3D. Referencing it is reinforcing your misunderstanding of the different requirements for 3D. Put it on a shelf where you can't see it, and won't be tempted to read it again. Mine is in numerical order with other Workshop Practice Books; I haven't opened it in ages.

As you've discovered, it's very easy to draw figures that look connected, parallel or whatever, but aren't. That doesn't matter (much) on paper, but it's deadly in CAD. Constraints are used to ensure the geometry you've drawn is and remains what you want, as their names demonstrate: perpendicular, concentric, symmetrical, parallel, colinear, coincident, mid point etc etc. They're vital, and are normally used before dimensions.

Informal exercises are important, but inventing your own will lead you down frustrating paths. Try simple parts that you already understand. A T-nut, simple split clamp then a U-bolt would be a good start for many of the processes. There are several ways of creating these, as a few minutes in front of the computer for each will prove. Some are much better than others even though the end part will be identical.

Time for some construction lines.

Draw one horizontally near the origin, so that you can see it move when you constrain it to the origin. Doing this means you know that the line is where you wanted it, not just looking like it.

Create the first circle on the origin, and the second one on the line. That enables you to add easy(and easily editable) dimensions. Do the same for one of each of the cover holes, so you can use a radial pattern once they're actual threaded holes in the solid.

Draw the outside profile of the part, dimensioning it from the origin, construction line and centre holes as necessary. DON'T use coordinates for this, for a couple of reasons: it's lots of extra work which the computer can do better, but mostly because it's what is causing your model to break when you try and alter it later. If the thing is symmetrical, you only need to draw half and mirror the other which saves time, effort and potential screwups. This is basic 2D draughting, so is well within your previous experience.

Extrude it, so you now have the solid you actually want. Work on that, creating extra planes and 2D drawings for the required features. And it should only be moved, placed, aligned or joined using the program's tools NOT moves. Because as you've found, moves are another excellent way of breaking the model in all sorts of random ways.

TurboCad is horrible to use, but all of the above applies to any of the programs.

I've never moved anything using coordinates. It's the CAD equivalent of measuring off a print and hoping that everything works out OK.

Your 'hard to manipulate reference points' are what the computer provides to save you the calculations. A differential would have the reference point(Fusion calls them joint origins, and they can be vertices, edges, faces, hole centres, additional points or any other feature) where the centres of the pinion and ring gears meet. Or the pinion flange. Maybe one of the halfshaft flanges if you're weird. You would then use a relevant joint type to place that to your axle centre line. The joint function also allows you to offset it in any of the three main axes, and/or rotate it around them. So you could initially set the pinion angle, and skew the axle across the frame if you were modelling a Renault. And alter either angle when something else changed.

All these programs will display grids on planes, and the main axes. They also allow you to turn them off which is preferable.

Once again, your approach is causing your problems. We keep saying that you need someone to show how any of your parts could be produced using a program you already have.

As we showed in a previous thread, your chassis rails are not nine separate operations each, but two simple, editable sketches and another editable procedure. Then you create a mirror of it for the other side. That makes you the designer, with the computer as a tool.

Coordinates are another deadly trap: let the computer use the features on the parts to position/align/join them. You won't assemble the real thing by moving the boiler back 30.56583mm and up 23.9 from the front crossmember and ground, but shift it until the mounting holes line up.

The elevations you need(I would prefer want, but I suspect we work differently) are then taken from the model because it already has ALL of the information. You can create as many as you need, showing the whole machine, separate parts or how sub-assemblies relate to each other. Again, that's being the designer.

Your 3D model is the CAD equivalent of a back of an envelope sketch, which is then used to start the design and figure out how you're going to do it - the traditional drawings of complex parts weren't created by just grabbing paper and pencil and drawing away. A considerable amount of training, practise, experience and thought was used first.

Twenty years ago, I decided that I should have my own lathe rather than pestering friends to make my random parts. It had to fit on a bench, and Myford was the only name I'd heard of. So I went and looked at several listed in the local Freeads. Buying any one of them would have been a mistake for someone who had never used a lathe before, as they had been animals they would have been booked in for a oneway trip to the vet. Looking back, even if I looked at them now I'd walk away laughing at the audacity of some people to encourage a buyer to look at their festering scrap.

I had jobs to do, so eventually walked into Machine Mart and bought a CL300 mini lathe for a third of the price of the cheapest scrap I'd looked at. An hour after getting home, I'd made my first, very simple, parts. Fifteen years later I upgraded to a larger machine(mainly to improve productivity) and sold the CL300 and most of the accessories for what I'd originally paid for the lathe.

The point of this ramble is that an inexperienced user is going to really struggle learning on a machine that would challenge a competent operator. And that a mini lathe is a very handy thing to have even though they're a lot more expensive than they used to. The sheer portability of the thing is particularly handy, as it can easily be moved on and off the bench as necessary.

Pat, the other thing to do when that happens is to ask somebody competent for advice and actually listen to it. How many threads have we seen recently that have ended with the OP flouncing off after being told that his design/parts/approach is never going to work and starting over will save throwing more good resources after bad?

Nigel's bald statement that CAD(of any sort) doesn't make you a better designer shows he really doesn't understand its value power.

Yes, there is a steep learning curve(just like being able to produce a presentable drawing of a part with pencil and paper) but once you've started up it the benefits become clear: you don't have to do all the extra stuff of drawing the features onto the other planes, because the computer does it automatically. Same applies to how far a hole needs to go; is it 34.76849mm or 45? Who cares - click All and it's all the way through/butted up to the next part, or your hard to draw 7 hole bolt pattern is cut into both parts complete with countersunk holes and threads. And they're the easy things, who wants to do the maths to add an angled hole tangential to a seemingly random curve. Again, the computer doesn't care, it just does it allowing your thoughts to be of the design, not the details.

Anyone who can confidently draw a real object by the traditional 2D representations ought to be able to fall into 3D CAD, as the hard part is often deciding which profile to sketch to get your initial solid - should you use the front because it's symmetrical, the side because it has the most/least features, the top because it joins to another part and you can use that to start with, or revolve your multi-feature spindle around the axis of the bearings it sits in? How about modelling your motor mounts directly off the motor you carefully aligned with the pulleys it drives.

And why the insistence that 2D workshop drawings are the end result? A folder full of pretty drawings is just another step like ringing round suppliers to find a decent price on the materials, not the final objective which is having a working part.

I would make the flanges back from the ends for the reasons mentioned, but would include their diameter(s) in the original, central sketch. A central bore could also be included, but that's enough concentric features to justify sketching the profile and revolving to create the solid.

As for Dave's door bolt, I would have modelled the bolt inside the body, using projections of its axis, diameters and notch positions. That removes the need to figure out where the new features need to be, and makes creating the joint and its limits much simpler. As a design approach, the notches in the body could be left until last and placed by sliding the bolt to and fro in its bore.

Fusion allows you to pick where you join parts, or to place Joint Origins at known places. It then gives you the option to offset and/or rotate the parts when you actually join them:

Parts, the multi coloured features are the Joint Origins:

Rigidly joined together using those origins:

And you didn't ask for this, but cut the centre of the joint using the tube's inner profile:

The original sketches show in some of those pics, and you'll see they aren't closed profiles. Instead I used the Thin Extrude command which saves a lot of time. Also, only half the clamp body was drawn and extruded, then it was mirrored about its central face which also saves time and simplifies the sketch

Using nothing more than string and the power of stubborn thinking

I hope you've checked that it's the same as the one you sent in. The DVLA are notorious about removing classes that you're entitled to drive, like motorcycles or HGV. Then when you contact them, they check on the same computer that produced the error and you have to prove they screwed up.

Make a copy of your licence before you send it to them!

Those knobs are nicer to use and look so much better than knurled ones

Thank you for that.

Oversize ER32 collets are now on my need to get list