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21
From Plans / Re: Ohrndorf Valveless 4 strokes
« Last post by Admiral_dk on Today at 12:11:25 AM »
I realized that my comments sounded negative, and I'm sorry if they came around that way, as I really hope that you will enjoy the experience  - even if it (maybe) gives you some challenges along the way  :cheers:

Best wishes

Per
22
Hints, Tips & Tricks / I Have Decided to Hacksaw My Nuts Off
« Last post by Captain Jerry on Today at 12:00:36 AM »
The only way to get tall nuts is to make your own.  I have made a few in the past but my current project is going to need about 36 tall #2 -56 nuts.  I have used 303 stainless hex and parted them off after tapping but I seen to loose more than I make and there is still a bur to remove and chamfer to add.  On top of that, since you can only tap about 5/8" deep with a #2-56 tap, you only get 3 useable nuts, allowing for parting tool loss for each setup.  A slow and laborious process at best.


Today, I decided to get serious and get some production going.  The first step was to keeo from loosing them so used a short stud a a #2-56 large pattern nut.  After cranking the nut down against the shoulder, I ground off the threaded shank to leave 3 full threads.  This will be used as a mandrel for polishing and chamfering the nut after cutting off.


The hex stock is drilled and tapped in the lathe as you would expect.  The three exposed threads are then screwed into the stock, tight up against the large pattern nut.  The mandrel is only an inch long.  I then use a special gauge ( small needle nose pliers) to set the exposed length of stock to the desired height of the nut plus the thickness of two steel washers.  The washers are slipped over the end of the mandrel and the large nut to act as a guide and to protect the jaws of the lathe chuck.  Using a small hacksaw against the second washer, I cut the nut off.  I drops into a small tray under the chuck, and because it is attached to the mandrel, it doesn't bounce around and get lost.  I pick up a file and file the end of the stock in the chuck to remove any burr and the pickup the mandrel with nut still attached from the tray.  A five second twiddle against the belt sander to remove any burr and add a little chamfer.


Take a breath and repeat.


I can get four nuts before needing to drill and tap again.  My tap drill wanders off center very slightly but I can get three sets before the hole has wandered off center enough that I need to clean up the end of the stock with a parting and respot with a center drill.


After I got the process worked out, I was able to 40 nuts in less than an hour before running out of stock.


From now on, I will hacksaw my nuts off.


Jerry
23
Vehicles & Models / Re: Chris's Marion 91 Steam Shovel
« Last post by crueby on March 23, 2019, 11:48:41 PM »
The rest of the crosshead pins are done and installed. Next up... Ummm... Coin flip... The eccentric followers!
24
Tooling & Machines / Re: Leadscrew
« Last post by steamer on March 23, 2019, 11:10:06 PM »
And a sketch of the outside of the bearing mount.

I'll need to sort out the geometry internally now

25
Tooling & Machines / Re: Leadscrew
« Last post by steamer on March 23, 2019, 11:07:11 PM »
Here's the assembly that will not come apart....

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Tooling & Machines / Re: Leadscrew
« Last post by steamer on March 23, 2019, 09:31:47 PM »
I'll be making a new bearing as well.   The existing bearing is screwed together and then staked.    It is NOT going to come apart...no matter how I try

So I'll be drawing the whole thing up, meanwhile, I have a project for Kim I need to do

Dave
27
Your Own Design / Re: Design and build side shaft hit and miss engine from bar stock
« Last post by Art K on March 23, 2019, 09:29:57 PM »
Brian,
Sounds great, obvious hit & miss cycles. Happy dance time! Unfortunately samsung doesn't have dancing elephants.
Art
28
Additive Machining / Re: Electroforming/electrotyping
« Last post by sorveltaja on March 23, 2019, 09:27:41 PM »
Ian, thanks, that's actually my plan B, if all else fails. But I just have to try out the ''diy options" first. Cant't help it. 

I managed to construct the dual diaphragm pump, but oh boy that thing is one noisy bugger. Sounds like an air compressor.

So I got back to centrifugal pump. Today I tested magnetic coupling, with some 10mm diam. neodymium button magnets, but not enough drive force. Putting a hard drive magnet to the motor side
increased the traction as was expected. Next step is to test it with water. It has two stainless steel parts in the pump chamber, that are to be exposed to the liquid.

If all goes well, I should be able to put it to use in couple of days, to feed eductor(s), or some other 'random flow generator'.
29
From Kits/Castings / Re: Newbie building a PMR 6CI
« Last post by b.lindsey on March 23, 2019, 09:05:19 PM »
Nice little shaper and looking better already. If you want to document the restoration I would suggest themachines and tooling sub fora.  Let me know if you wish and I can move the posts about it there for you.

Bill
30
Restoration of Model Engines / Re: How to keep busy for the next 20 years!
« Last post by simplyloco on March 23, 2019, 09:01:21 PM »
Thanks Kim: it's worth the effort because this will be my 'Show' boiler at Club events. I'll have a few engines on a board and I'll let the little kiddies burn their fingers on them... :mischief:
John
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