Tag: fusion 360

CAD CAM software

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Tap shank adapter for 4mm AF hex drivers

Useful 3D printed adapters for hand tapping 3D threads

I usually 3D print all threaded holes as a modelled thread rather than tapping drill size hole which would need full post print tapping. As the intended thread size of modelled threads reduces so the print quality of the thread can be a problem. This usually leads to a quick post print run through the thread with a manual tap.

Thread quality and strength can be improved by increasing the number of perimeter prints via the slicer software. This makes the printer add extra print lines around all external surfaces before it does the infill. This is even more important if you are going to use brass inserts for your threaded mountings as it gives the insert more plastic to melt into.

The problem with post print clean up tapping is getting the tap to start perpendicular to the already printed tapped hole. If the hole is small (say M2) the size and mass of the tap holder adds to the wobble difficulty of getting it ‘plumb’.

In the past I would mount the tap in a small toolmakers chuck as this gave an extended length to the tap for the eye to judge the ‘plumbness’. I didn’t have enough chucks with the right size collet to cover all tap shanks.

Some time ago Clough42 recommended a small electric screwdriver that had 4mm AF inserts. I found this one on Amazon. There are also many other electrical and manual screwdrivers that use the 4mm AF insert standard.

It struck me that if I could make a set of adapters to mount in the screwdriver chuck to hold the tap shank this would ease the post print tapping problem. The length of this particular screwdriver body gave a better ‘to the eye’ perpendicular check. The added ability to electrically drive the tap meant that the perpendicular setting was more easily maintained. The speed and torque of the driver would also act as a break clutch.

I debated a lathe activity but then thought why not a 3D print? I created a model in Fusion with Parametric functions for the tap AF dimension and square driving section length.

Not all taps are created equal so these two parameters can be easily adjusted using the parametric function to match your tap sizes. Print time was around 9 minutes on my Qidi X Smart. I printed the adapters in PLA+ vertically off the bed as shown and in 0.2mm layer height. I set the slicer for 6 perimeters on the print, a 6mm wide outer brim for build stability and auto support off the build plate.

The adapter boss section will accomodate up to M5 size tap shank dimensions (3.9mm AF, 8mm length). Any size greater than M5 will usually print very clean and not need post print fettling.

Here is the Fusion file for those interested.

tapping adaptersDownload

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Eccentric Engineering Turnado freehand turning tool

Better to have it and not need it etc

I have had an Ingram (1905) mechanical clock in for service. A simple clean and set to time which went to plan (for a change). The only niggle was one of the four tapered wooden pegs that hold the dial and movement into the wall case was missing. I could have 3D printed a tasteless replacement but my conscience would not let me stoop that low. It needed to be a wooden part with similar geometry.

Quite some time ago I had ordered a pair of Diamond Tool Holders from Eccentric Engineering in Australia and at the time Gary was doing a special deal on his Turnado hand turning tool. As I was going to be paying a significant carriage cost I decided to consolidate and offset this with the Turnado kit.

On receipt of the package I played with the Turnado but had no needing projects at that time. It is well thought out and allows freehand turning either as freeform movements or movement against a template profile or with a pantograph. Here is a link to Gary’s sales video.

In the process of considering making a 3D printed version of the peg I had dimensioned and drawn a 3D model in Fusion.

Taking the 3D model and opening it in Fusion Drawing mode gave me a 1:1, 2D PDF drawing of the peg. I cut out the 2D image and stuck this to a piece of aluminium with 3M Spray Mount and then nibbled and filed the aluminium to the peg drawing profile.

The profile template was mounted on the Turnado working table and the shape profiled into a piece of 18mm dowel using the Turnado tool on its pantagraph following my profile.

Here is a posed picture of the setup showing the Turnado tool and table with my profile plate, for effect a first attempt at the peg is sitting in the chuck between centres with the original peg (LHS) and the finished peg (RHS). Not quite a total match but more than functional.

Absolute magic. A really useful asset. I just need to remember I have it ….

As Jimmy Diresta would say “Better to have it and not need it than need it and not have it”

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Fusion Electronics Library Notes and Crib Sheet

An attempt to clear the confusion in my head

After spending many hours going round in circles trying to create new custom library parts in Fusion Electronics (FE) I gave in and posted a plea for help on the FE forum. I received some helpful replies but not sufficiently uplifting to put me at ease with the process.

As ever my nerdy side stepped up and armed with this new knowledge I set about learning the process step by step in a way that I could understand it and more importantly repeat it successfully.

The result of this is a 30 page document that can be downloaded from the link below. This contains the library process, a help crib sheet for using FE and the copies of the original support replies I received from the FE forum.

It may not be perfect and it is a work in progress so feel free to give me feedback on errors and content changes. Remember it is based on Fusion Electronics as of May 2025 with build version 2602.0.71. As I learn more I will update the contents and re-post.

I hope it helps someone, somewhere, sleep better. The length of the waffle will almost certainly guarantee the latter.

Fusion Electronics Library Guide and Crib Sheet v4Download

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3D Printed Threads Modelled in Fusion 360

Tweaking the geometry

I recently posted an idea for a 3D printed depth setting jig for use on my Myford Big Bore lathe. A couple of readers had run the STL files and struggled with the fit of the mounting boss thread (M35 x 1.5) that mates with the thread on the end of the lathe spindle. This is a known problem with 3D printed threads where the accuracy of the 3D printer and the size of the thread being printed can interact and have an impact.

Fusion 360 does not have a tolerance tweak in the thread creation tool. This is not a problem in that you can use the Face Offset tool to adjust the thread geometry. This does not take long to do. The process also allows you to add fillets to the thread peaks so they are less aggressively ‘sharp’ and therefore more likely to survive longer.

Select the Inspect/Section Analysis to view the cross section of the thread to be adjusted. Choose any axis for this. Manipulate the view so you can see the cross section face and the around to the side of the 3D model. Do the tweaks shown below by selecting the appropriate faces of the thread and making an Offset Face adjustment and then adding a chamfer. The difference is very minor but it makes the thread less ‘sharp’ and aggressive to its mating half which is likely to be a metal component. If you are working with a modelled threaded hole rather than a rod then the changes are the same. The values shown are nominal and will change with the modelled thread size. If you overdue the offset the thread will become very sloppy.

The only tricky part is Manipulating the view in Fusion to allow the appropriate face selection otherwise the Offset command is straightforward.

To a degree some of this could be achieved in your 3D slicer but adjustments would become global rather than specific to just the thread geometry.

If you want a more detailed explanation then I suggest you watch Kevin’s post on Product Design Online.

I have modified the geometry of the Depth Setting boss threads to give more tolerance and reposted the STL to match on the link below.

Myford S7 Big Bore Depth SetterDownload

If you have a Myford Small Bore lathe and would like to send me the bore size and end thread I can create a new version of the depth setter to match.

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Simple Water Level Sensor for Live Steam Locos

Avoid a panic half way round the track

While coming to the end of a running session of my 5″ loco at the club raised level track I suddenly realised the axle pump was not making its normal rattling noise. Water level was likely very low and there appeared very little in the glass sight gauge. My state of panic endured until I reached the filler hose.

On returning home to the workshop I resolved to try to make this alarm situation more readily visible. The common solution is to add a second sight glass feeding from the water tank and visible in the ‘cab’. My engine did not have a great deal of room for this addition.

Sacrilegiously I began to consider an electronic solution which probably wouldn’t make me popular with the mechanical diehards but the challenge appealed.

The electronic solution turned out to be a multi faceted activity. An initial bird’s nest lash up was followed by a PCB designed in Fusion 360 Electrical. The PCB was milled on my vacuum table fitted to the Tormach 440 with the Gerber and Epsilon files converted to GCode using FlatCAM. Having completed the PCB board this led to a customised enclosure designed in Fusion 360 and 3D printed in the Qidi X Smart 3.

The circuit is a NPN transistor that is turned on by water conduction between two sensor probes which in turn drives a second NPN to illuminate a flashing LED. The module is powered by a CR2025 button cell.

The enclosure consists of three parts, the base, a snap on lid and a round boss that matches the diameter of the water filling hole on the engine side tank. The two water sensing probes are made from 16 swg wire protruding from the boss.

The round boss is held in place with a M2.5 countersink screw and could be dimensioned to suit different sized filler holes. Having it as a separately printed item is also useful in that it allows the enclosure base to be 3D printed without support.

Here is are some views of the completed assembly.

It seems to work quite well and is surprising sensitive down to the last few millimetres of the probe rods. Time will tell.

If you want more details then please send me a message.

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