View Full Version : Looking for advice on the designs of these components for 3 axis CNC milling.

Neil C
12-07-2017, 11:07 AM
This is part of a product Iíve been working on for the last year or so and I am at the point of making up a prototype. Part of the design requires 13 or 17 of these joints. They are aluminium and Iíve tried to design them in such a way they can be cut on a three axis CNC mill.

So now Iím looking for someone with a three axis CNC or who uses a CNC to look over the drawings and point out any problems or ways that the designs may be improved so they are easier to produce.

There are 4 different designs and one set is 17 units. X2 x4 x7 x4, though there are some small variations like different counter bore depths for the bearings.
I presumed that when cutting them you would cut several from the same length of bar at once. Is that possible? And is there anything I need to take in consideration in the design to make this easier?

Iíve designed them so all the parts can be milled from the same square bar but at the moment most are 42 x 42mm and it may make it easier to make them all 44.45 x 44.45mm, so they can be cut strait from bar bought off the shelf, 1 ĺ inch. It would mean some compromises in the design but if it made them much cheaper to produce it might be worth it.

Iíve made them so they all have two sides to cut with a flat base to lay them on and parallel sides to clamp them but again it would be a real help to have some who is used to 3 axis CNC milling look them over.

And then also Iím looking for someone in the UK who would make up this first set.
Any advice welcome, all the best, N.





12-07-2017, 08:20 PM
Hi Neil.

Is it possible you can send me the Cad files? Ideally a model would be far better for these at 1 to 1 scale. I can take all file types but a Stp or Step is best for my software.

You can find my email in the sig below or i can pm it to you if needs be.

Please also include the quantities for each type for the proto types and also realistic expected quantities/ batches in the future.


Neil C
12-07-2017, 10:01 PM
Sounds good. The link below took me through to Ward Engineering and there is an email there starting with scott..., sound like I'm in the right place? I'll include all the details you are asking about in an email with the files first thing in the morning. Step has two flavors I can export in, AP203 or AP214, any preference?

13-07-2017, 03:36 PM
Hi Neil,

yes that is me, you are in the right place. I didn't want to repeat my mail here otherwise the bots would pick it up in time.

I think try AP214, as this version covers layers and colours it seems, we can only try!


14-07-2017, 11:18 PM
Multiple comments, some may be useful..

Do You really need the 1. with bulging head, be milled out for the round profile at top.
It is like old casted/finish machined bits, yes.
But could it no be a flat slab, of same accuracy ?
Much faster and cheaper.

2. Rest..
Do you need accuracy, or is "good finish" acceptable on the rounds, ends, tapers .. ?
Much faster and cheaper.

I suggest making a doc. explaining needs, uses, tolerances.
Would likely drop cost 50%.

Whats Your timeframe.
Material ??

Qty ? now ...
// yr ??

Neil C
16-07-2017, 11:38 AM
Hi hanermo2, I did't get notice of your post for some reason so sorry this such a delayed response.

These are connecting blocks for 31.8mm tubing, tube to tube, tube to plate and tube to axle with bearings. Good finish is acceptable everywhere except inside of the counter bores ether side of the bulging head parts, these are to hold bearings so interference fit. There are no other contact or clearance critical surfaces on the parts. So good enough is good enough.

The bulging head. The amount of each part to make one unit is x7, x4, x2, x2 in order respectively. So the bulging head or number 1 makes up a large proportion of the parts. I have it drawn up simply as a block too, but weight if not accuracy is a critical issue on these parts and straitening the sides will take the part from 161g to 235g. this will be a 28% increase in the overall weight of the parts. So yes I can have it just as a block but it's a big compromise so I'd like to see what the difference in cost to machine would be.

Material, that was daft of me. I've been staring at these so long I forget the obvious. It's 6061, T6 probably but aluminium to be sure.

This is to make up a prototype and then we'll need to spend some time testing. If it’s successful we’ll look at a patent and putting it out there and seeing what kind of reaction we get. Then based off that we’ll do a first run. But even if these were very successful the numbers would be small, it's a very specialised product.