Joe's 1000x600x200 steel and aluminium router started

[devmonkey]

I'm well pleased with the trocho pocket plug-in, it's a major step forward in being able to make hardwood clock wheels sucessfully.

How are you designing the ring of teeth for the pulley? I have the Gearotic software which can create accurate timing pulleys in all sorts of formats. If you need help with that I can send you a PDF for importing into CamBam (that's another plug-in).

Well if you want to get into a new hobby that involves playing with fire, melting aluminium is easy. The YT video below gives you the idea. Use previously cast aluminium alloys (old water pumps from your friendly neighbourhood motor mender etc.) rather than cans or other scrap. Sawing off the bottom of an old fire extinguisher makes a good crucible. Getting a sucessful cast with it is another story however.

Not sure on the use of 2-part plastics for something this robust or how well they machine but one option to consider is to make a master in MDF with your CNC machine and then a silicone mold to cast the final pulley ring, or a blank for final machining. I've done a bit of this for arty stuff but not for engineering. You aren't going to buy from Australia but the Barnes site linked below has info on materials and how to use them. Similar stuff will be available in Pommieland.

https://www.barnes.com.au/

https://www.youtube.com/watch?v=lSoWxG30rb0

Good luck

Kit

I use a free command line dxf generator that can generate all of the main timing pulley profiles, super simple.

I just cut an 8m test pulley in 10mm SRBP P1, if came out very nice and extremely strong teeth. I think I will use this material and laminate a few layers together then bolt through, it is pretty cheap stuff and locally available to me.

[Clive S]

I use a free command line dxf generator that can generate all of the main timing pulley profiles, super simple.

I just cut an 8m test pulley in 10mm SRBP P1, if came out very nice and extremely strong teeth. I think I will use this material and laminate a few layers together then bolt through, it is pretty cheap stuff and locally available to me.

That's cheating. Do you have a link for it.

[devmonkey]

That's cheating. Do you have a link for it.

Here you go, https://github.com/paulius-zubaviciu...file-generator

You need java to run it.

[devmonkey]

I made the large timing pulley I was proposing today, it is a 157 tooth HTD 8M (20mm belt) for a project, pulley is ~400mm diameter. It was made from 10mm SBRP with 3 laminations at the rim. Turned out fantastic. I used screwfix cyano to laminate, this makes a very strong joint which you cannot get apart. It will never the less be reinforced with a ring of M5 bolts.

[Voicecoil]

I made the large timing pulley I was proposing today, it is a 157 tooth HTD 8M (20mm belt) for a project, pulley is ~400mm diameter. It was made from 10mm SBRP with 3 laminations at the rim. Turned out fantastic. I used screwfix cyano to laminate, this makes a very strong joint which you cannot get apart. It will never the less be reinforced with a ring of M5 bolts.

What a monster? what's it for may I ask?

[devmonkey]

What a monster? what's it for may I ask?

It is for winching humans into the air attached to paragliders, this pulley forms one side of the winch drum and is driven at around 10kW by a 25kW BLDC motor under FOC control.

[Kitwn]

Nice! It's very satisfying when the machine you have put so much time and effort into designing and building starts to produce that kind of output.

[Evengravy]

Seconded, that's a lovely piece of work.

[devmonkey]

Tool deflection chaps, tool deflection!

So I received a bunch of single flute endmills from China, these things cut aluminium and SRBP nicely. However I'm having some problems, and would like your diagnosis,

So I've just cut a bunch of parts that need a hole that is a reasonable sliding fit on a 25mm shaft. I used one of my new 4mm single flute endmills, 2mm DOC, 1600mm/min into 10mm SRBP. It cuts like butter. However when I measure the hole afterwards it is larger at the top than the bottom by about 0.15mm, effectively the hole is tapered. If I cut the same hole with my usual 6mm 2 flute it is straight.

I assumed this was the single flute deflecting on subsequent deeper passes but it could also be that the endmills are themselves tapered?? What do you think?

I guess the solution is to rough with the single flute and finish with the 2 flute, just a bit of a hassle.

Also could it be that i'm spinning them too fast a 24krpm and they are bowing out due to centrifugal forces?

[Voicecoil]

What happens if you take the feed rate down? And how long is the flute on the single? greater than the depth of the material?