Another Paddleducks build log

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Stilldrillin:

--- Quote from: spuddevans on August 02, 2009, 04:29:26 PM ---
--- Quote from: bogstandard on August 02, 2009, 04:19:21 PM ---Just one criticism Tim.

If you look at commercially ground threading tools, you will notice that the left hand side is ground away as much as possible. If you did that, you could turn almost to the shoulder without it cutting the chamfer under the screw head.

Bogs

--- End quote ---

That's a good idea, never thought of that, I'll have to grind up a off-centre threading tool. :thumbup: :thumbup:

On these screws the chamfer was created by the round profiling tool, I thought it looked kinda nice and it had the additional plus of allowing the (oversized) threading tool to get close enough.

But I will definately grind up a better threading tool that'll allow threading closer to a shoulder.

Tim

--- End quote ---

In my "he`s right" pic, you can see I use a blade type parting tool, ground for small scale screwcutting. :thumbup:

David D

spuddevans:

--- Quote from: Stilldrillin on August 03, 2009, 01:56:03 AM ---In my "he`s right" pic, you can see I use a blade type parting tool, ground for small scale screwcutting. :thumbup:

David D

--- End quote ---

Ahh (goes back and looks at the pic again) I missed that the 1st time I saw your pic. I definitely will grind up something similar the next time I have to single point a thread.

Thanks :thumbup:

Tim

Darren:
I missed that too David, thanks for re-pointing it out to us.

I'll be grinding one of those up myself as well..... :thumbup:

Stilldrillin:
Yer welcome Chaps....... :thumbup:

Sometimes I`m not sure if, "everyone knows that"...... Or not! ::)

David D

spuddevans:
So I got a little more done today. I started by making the 2nd packing gland. I didnt take any pics of this, but here's one of the 2 packing glands in place.

I then made a start on the piston assembly, starting by roughing the pistons to within 1mm of final size, drilled and then tapped M2.5 and then bored 2.5mm 1mm deep to allow the rod to seat properly.

then parted off approx 6mm and repeated to make the other piston.

I then started on the rods, and following on from the single point threading thread I was determined to single point it. However, the chart of gears for my lathe did not list 0.45mm pitch as an option. After some not inconsiderable head scratching and vain calculations I gave up and came indoors to download Mklotz's "Change" program, entered my leadscrew pitch and the change gears that I have and it gave me a solution.

Back out to the workshop and a few mins later I was ready to cut. 1st off I centre drilled the end of the rod and brought up the tailstock with my new ball-raced center. Then it was just a case of making a few passes to get to near depth.

Then I removed the tailstock and finished the thread form off with a Die.

Then did it again for the other piston. Then I assembled the bits with some loctite and set them aside to set.

And that's all I got done today. I'll start on finishing the pistons tomorrow, and then on to the crossheads.

Tim

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