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Gallery, Projects and General => Project Logs => Topic started by: mickn on July 28, 2009, 05:58:42 PM

Title: Making sacrificial gears from Delrin
Post by: mickn on July 28, 2009, 05:58:42 PM

Being a bit overzealous with the amount of cut I was taking whilst flycutting  I had one of those horrible moments. A nasty clunk and then the machine stopped! What have I done? Off with the covers and delve into the inner workings. I had sheared two plastic sacrificial gears in the milling head. I loathe anything made of plastic. Its hard to repair it’s not like metal which can be riveted brazed and welded. Anyway it had done the job it was designed for, and stopped anything major happening.I phoned the machine supplier and ordered new gears.I thought they are expensive for what they are and decided to have a go at making some myself. I remember from apprentice days learning about gear cutting addendums dedendums pressure angles etc. I cant be getting into that so I thought take the old gear and hand grind a piece of  toolsteel to fit the form of the gear tooth I needed. This I did, then I ordered a piece of Delrin off of ebay and cut myself some blanks to match the damaged gears. I then turned a tight mandrel to take the blanks the straight cut spur gears were fairly easy but the helical gear posed more of a problem. I solved it by tilting my dividing head with packing to give the angle required. This vid shows the making of the helical gear. Ok Its  not proper gear cutting but its good enough for my needs

Regards Mick

Title: Re: Making sacrificial gears from Delrin
Post by: shoey51 on July 28, 2009, 06:39:58 PM

 :thumbup: :clap: great work :D

Title: Re: Making sacrificial gears from Delrin
Post by: bogstandard on July 28, 2009, 10:41:19 PM

Very nicely done Mick.

You showed two things on there to great effect.

The first was that with a little thought, these difficult bits can be made fairly easily.

The second showed just how easy it is to fluff it when working with a dividing head. A quick lapse of concentration and you can soon be in trouble. Luckily, your fluff had an easy remedy.


Bogs

Title: Re: Making sacrificial gears from Delrin
Post by: sbwhart on July 29, 2009, 02:07:41 AM

Well done Mick  :clap: :clap: :clap: :clap:

Nicely shown.

I'll file those methods away for future use  :thumbup:

Have fun

Stew

Title: Re: Making sacrificial gears from Delrin
Post by: Darren on July 29, 2009, 03:23:29 AM

Nicely shown Mick, you make it look so easy.... :clap:

Title: Re: Making sacrificial gears from Delrin
Post by: Mike K on July 29, 2009, 06:00:17 PM

Plus a third thing: Why make one when you can make two just as easily.

Nice job, Mick.

Mike