Author Topic: Its a steam engine... Vaguely based on the PM Research #1  (Read 717 times)

Online propforward

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Re: Its a steam engine... Vaguely based on the PM Research #1
« Reply #15 on: April 02, 2021, 06:23:11 PM »
That is absolutely BRILLIANT. I have never seen that donut drill bit approach before.
Stuart

Offline bent

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Re: Its a steam engine... Vaguely based on the PM Research #1
« Reply #16 on: April 02, 2021, 06:30:42 PM »
There are some chemical methods that might work, info in the link:
https://www.practicalmachinist.com/vb/general/broken-tap-removal-chemical-methods-198135/

Offline Josh-MMS

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Re: Its a steam engine... Vaguely based on the PM Research #1
« Reply #17 on: April 03, 2021, 12:47:47 PM »
Thanks for all the advice chaps, that donut drill is an interesting idea. Realistically I can only go up to M4 so let's see if I can make one of them with a 3mm bore and 3.5mm OD... I shall report back.
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Offline tevans9129@charter.net

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Re: Its a steam engine... Vaguely based on the PM Research #1
« Reply #18 on: April 03, 2021, 02:04:40 PM »
One mans trash...

Unfortunately I had a little bit of a setback yesterday.

Snapped an M3 machine tap in the cylinder block...  :Doh:

I've tried a few ways of getting it out with no luck so I'm not sure what to do now. I think it'll run fine with only 3 bolts but it'll look awful.



Just for looks, can you Loctite a cap head over the broken tap?

Offline Josh-MMS

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Re: Its a steam engine... Vaguely based on the PM Research #1
« Reply #19 on: April 03, 2021, 02:55:35 PM »
A short story in pictures...

Yes I'm going to glue a cap head over it  ::)

We live and learn...
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Offline Kim

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Re: Its a steam engine... Vaguely based on the PM Research #1
« Reply #20 on: April 03, 2021, 05:23:53 PM »
That is unfortunate.  The tool looked nice before you applied it.  What kind of steel did you use to make the donut drill?  Did you heat treat the tool before use?  That would be important.  Also, you could make the cutting circle a little thicker, which could provide additional strength.

You're drilling into aluminum, right?  So that shouldn't be that tough.

Kim

Online propforward

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Re: Its a steam engine... Vaguely based on the PM Research #1
« Reply #21 on: April 03, 2021, 06:11:30 PM »
It was a valiant attempt, and was worth a try.
Stuart

Offline Josh-MMS

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Re: Its a steam engine... Vaguely based on the PM Research #1
« Reply #22 on: April 03, 2021, 06:12:00 PM »
It was made from silver steel, W1 I think. Yeah I hardened it, sharpened it and tempered it back to straw.

I was hoping to use it to get the tap out and produce a hole I could tap M4, any bigger than that and I'll be getting too close to the cylinder bore.

And yes it's aluminium, but I'm pretty sure it hit the tap. There's only a very small amount of tap left in there and it's been bashed about trying other methods so I doubt it's still in the same place relative to the hole position.

I knew it was a long shot with the side walls ~0.25mm but it was fun to try and next time I have a bit more meat to work with I'll definitely make another.
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Offline Kim

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Re: Its a steam engine... Vaguely based on the PM Research #1
« Reply #23 on: April 03, 2021, 06:26:50 PM »
Well, Josh, the Loctite method is a good one too.  I've used it before as have many others :)

Sorry, the donut drill method didn't work out for you.  You made a great tool!  but if it hit the tap, there's probably not a lot that would save it. I can feel your frustration.  Sorry, it didn't work out. :(

Kim


Offline gary.a.ayres

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Re: Its a steam engine... Vaguely based on the PM Research #1
« Reply #24 on: April 04, 2021, 10:54:02 AM »
Well, you gave it a go.

Looks like there wouldn't be much spare room around the hole for a bigger donut drill.

I find myself wondering if you will eventually make a new cylinder...