Author Topic: Flyboy Jim's PM Research #5  (Read 4211 times)

Online crueby

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Re: Flyboy Jim's PM Research #5
« Reply #45 on: October 22, 2019, 01:34:11 AM »
Given the choice between 3 and 4 jaw, I'd go with the 4-jaw, have found that it can be tightened down more, and holds more securely than the 3-jaw. Also, you can put a hold-down clamp into the slot around the rim (the screw adapter or the rotary table came with one, I think) that will keep it from un-screwing itself from the table, very important when milling!

Another option is to turn the mill vise on its side to grip the casting, though it may be too rough to work well.


However it is secured, use light cuts - that is a lot of leverage up to the base of the casting.

You mention getting the base perfectly centered to mill the bottom flat. Why? The base just has to be flat and perpendicular to the rest, why does it have to be centered?

 :popcorn: :popcorn: :popcorn:

Offline Dave Otto

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Re: Flyboy Jim's PM Research #5
« Reply #46 on: October 22, 2019, 02:06:38 AM »
Hey Jim

I have retrofitted both of my shop chairs to polyurethane wheels, they are about the size of roller blade wheels and not too terribly expensive; and they work great!
https://www.amazon.com/s?k=office+chair+wheels+for+hardwood+floors&crid=2XC6QY8WTV083&sprefix=office+chair+wheel%2Caps%2C218&ref=nb_sb_ss_i_2_18

Dave

Offline Flyboy Jim

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Re: Flyboy Jim's PM Research #5
« Reply #47 on: October 22, 2019, 02:19:28 AM »
Given the choice between 3 and 4 jaw, I'd go with the 4-jaw, have found that it can be tightened down more, and holds more securely than the 3-jaw. Also, you can put a hold-down clamp into the slot around the rim (the screw adapter or the rotary table came with one, I think) that will keep it from un-screwing itself from the table, very important when milling!

Another option is to turn the mill vise on its side to grip the casting, though it may be too rough to work well.


However it is secured, use light cuts - that is a lot of leverage up to the base of the casting.

You mention getting the base perfectly centered to mill the bottom flat. Why? The base just has to be flat and perpendicular to the rest, why does it have to be centered?

 :popcorn: :popcorn: :popcorn:

My reasoning for centering was that if the top was centered and the bottom was centered then the piece must be vertical. The 4 jaw does seem better for all the reasons you listed and I'll go that way. I just need to figure out how to ensure the casting is vertical. I might be over thinking this........not the first time!   :thinking:

Definitely very light cuts.

Jim

Sherline 4400 Lathe
Sherline 5400 Mill
"You can do small things on big machines, but you can do small things on small machines".

Offline Flyboy Jim

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Re: Flyboy Jim's PM Research #5
« Reply #48 on: October 22, 2019, 02:22:06 AM »
Hey Jim

I have retrofitted both of my shop chairs to polyurethane wheels, they are about the size of roller blade wheels and not too terribly expensive; and they work great!
https://www.amazon.com/s?k=office+chair+wheels+for+hardwood+floors&crid=2XC6QY8WTV083&sprefix=office+chair+wheel%2Caps%2C218&ref=nb_sb_ss_i_2_18

Dave

Those look great Dave, thanks.

Jim
Sherline 4400 Lathe
Sherline 5400 Mill
"You can do small things on big machines, but you can do small things on small machines".

Offline Dave Otto

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Re: Flyboy Jim's PM Research #5
« Reply #49 on: October 22, 2019, 03:09:09 AM »
Another option would be to mount it to the mill table bottom side down with some shims to bring it into plumb. This could be verified using a precision square and the parting line of the casting. Then a clean up cut can be made on the upper surface. Then flip it over and skim the bottom. You could do it in stages incase some adjustments need to be made.

I would need to go back and look but I think this is how I did the bottle frame on my Pacific engine.

Dave

Offline Dave Otto

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Re: Flyboy Jim's PM Research #5
« Reply #50 on: October 22, 2019, 03:15:05 AM »
It starts at post 31 on my build, as I indicate I didnít take any pictures of the initial setup; but it was pretty much as I described above.

Dave

Offline Flyboy Jim

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Re: Flyboy Jim's PM Research #5
« Reply #51 on: October 22, 2019, 03:21:51 AM »
Another option would be to mount it to the mill table bottom side down with some shims to bring it into plumb. This could be verified using a precision square and the parting line of the casting. Then a clean up cut can be made on the upper surface. Then flip it over and skim the bottom. You could do it in stages incase some adjustments need to be made.

I would need to go back and look but I think this is how I did the bottle frame on my Pacific engine.

Dave

That's a good idea Dave. I do have a some extra material to work with.

Jim
Sherline 4400 Lathe
Sherline 5400 Mill
"You can do small things on big machines, but you can do small things on small machines".

Offline Jo

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Re: Flyboy Jim's PM Research #5
« Reply #52 on: October 22, 2019, 07:38:10 AM »
Surus mentioned before you start milling anything you might want to do some Casting fondling :pinkelephant: and find the centre line down the casting so that when you mount it you will know that it is going end up with the ends matching the main bottle shape.  There is one centre to find down the open side and one down the solid side with the casting line (which could be slightly off the centre line).   You might also consider a little fettling first to make it easier to hold/mark the casting   :)

Edit: I like Dave's idea of milling the top and bottom flat by clamping the bottle on its side to the milling machine base  :thinking: How about bolting an angle plate to the milling table and clamping the casting vertically against that rather than trusting on just holding the bottom of the casting ... The casting is rather tall and if it moved while milling  :paranoia:

Jo
« Last Edit: October 22, 2019, 08:24:53 AM by Jo »
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Offline Flyboy Jim

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Re: Flyboy Jim's PM Research #5
« Reply #53 on: October 22, 2019, 09:26:24 AM »
Surus mentioned before you start milling anything you might want to do some Casting fondling :pinkelephant: and find the centre line down the casting so that when you mount it you will know that it is going end up with the ends matching the main bottle shape.  There is one centre to find down the open side and one down the solid side with the casting line (which could be slightly off the centre line).   You might also consider a little fettling first to make it easier to hold/mark the casting   :)

Edit: I like Dave's idea of milling the top and bottom flat by clamping the bottle on its side to the milling machine base  :thinking: How about bolting an angle plate to the milling table and clamping the casting vertically against that rather than trusting on just holding the bottom of the casting ... The casting is rather tall and if it moved while milling  :paranoia:

Jo

Thanks for the input Surus.  :pinkelephant: If I can ever find one, I'll send you a cast iron peanut to fondle.  :LickLips:

Jo, if there's one thing I have right now, it's plenty of time for casting fondling and fettling! I enjoy this kind of challenge, so will spend a lot of time figuring out the best approach and experimenting with setups. I really appreciate all the great input.

Jim
Sherline 4400 Lathe
Sherline 5400 Mill
"You can do small things on big machines, but you can do small things on small machines".

Offline Flyboy Jim

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Re: Flyboy Jim's PM Research #5
« Reply #54 on: October 23, 2019, 02:41:14 AM »
Another option would be to mount it to the mill table bottom side down with some shims to bring it into plumb. This could be verified using a precision square and the parting line of the casting. Then a clean up cut can be made on the upper surface. Then flip it over and skim the bottom. You could do it in stages incase some adjustments need to be made.

I would need to go back and look but I think this is how I did the bottle frame on my Pacific engine.

Dave

Dave, I played with your option today. Following Chris's suggestion, I mounted my 4 jaw chuck on my mill table, I machined both the top and bottom flat with the coke bottle fairly plumb. Now I've got a flat surface top and bottom which will make it much easier to use shims to get it perfectly plumb. I've got about 1/8" of material to remove, so lots of material to work with.

Felt good to make some swarf!

Jim
Sherline 4400 Lathe
Sherline 5400 Mill
"You can do small things on big machines, but you can do small things on small machines".

Online crueby

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Re: Flyboy Jim's PM Research #5
« Reply #55 on: October 23, 2019, 02:50:46 AM »
Picture!!!  Picture!!!   

Offline Flyboy Jim

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Re: Flyboy Jim's PM Research #5
« Reply #56 on: October 23, 2019, 02:55:50 AM »
Picture!!!  Picture!!!

Darn .......I knew I forgot something!  :shrug: It did feel somewhat like a momentous occasion!

I think I need to get a face shield. It was a little un-nerving sitting in front of the fly cutter (in fact I ended up doing the one legged stand for most of the operation!

Jim
Sherline 4400 Lathe
Sherline 5400 Mill
"You can do small things on big machines, but you can do small things on small machines".

Online crueby

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Re: Flyboy Jim's PM Research #5
« Reply #57 on: October 23, 2019, 03:09:52 AM »
On my Sherline I have several rectangular pieces of plexi that are handy shields, depending on the setup I pick a size that I can tape to the headstock to block chips. Also have leather apron and face shield when needed.

Offline Flyboy Jim

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Re: Flyboy Jim's PM Research #5
« Reply #58 on: October 25, 2019, 01:13:14 AM »
Got a little more "machine fettling" done today.

The opening at the top of the coke bottle was just under .625" so, since I didn't have a .625 reamer, used a .625" drill and drilled it out to true the hole up. The finished size will be .750".



I then turned a friction fit plug and center drilled it.





Now I can use a center drill to locate the plug and thus the top of the coke bottle directly under the spindle.



Next up is to locate the center of the bottom. I'm thinking I'll fit a plug (probably wood) to it as well.



Jim
Sherline 4400 Lathe
Sherline 5400 Mill
"You can do small things on big machines, but you can do small things on small machines".

Online crueby

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Re: Flyboy Jim's PM Research #5
« Reply #59 on: October 25, 2019, 02:13:11 AM »
Excellent! 


 :popcorn: :popcorn: :popcorn: