Machining Plastics - How to Make a Poppet, Regulator Piston Seat, etc
- Thread starter Ezana4CE
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You need to get more basic, how to properly setup the tooling to cut, don't do this and he'll never get it right.
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I have made post on this before...
One great Little Lathe to start on is the Taig tabletop Lathe.
It has big lathe features in a compact machine.
Like large adjustable brass gibs and cast iron bed..
It is a great Machine to start on... it won't break the Bank...
I have made Delrin Valve-bodies and Titanium taper Main Valves on it!!
So the Taig is very capable for its size...
One great Little Lathe to start on is the Taig tabletop Lathe.
It has big lathe features in a compact machine.
Like large adjustable brass gibs and cast iron bed..
It is a great Machine to start on... it won't break the Bank...
I have made Delrin Valve-bodies and Titanium taper Main Valves on it!!
So the Taig is very capable for its size...
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There are desktop CNCs like Pocket NC:
www.pentamachine.com The software is free(ish) - Autodesk Fusion.
But 5-axis is still expensive, and I haven't found a cheap conventional 3-axis desktop CNC - 5-axis is an overkill (I think).
Pocket NC Info — Penta Machine Co.
www.pentamachine.com But 5-axis is still expensive, and I haven't found a cheap conventional 3-axis desktop CNC - 5-axis is an overkill (I think).
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@CA_Variminter My mistake. I meant to ask about the piston seat for a regulator. But I’d love to learn how to make my own valve stems as well.
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The reg piston seals are just a small cylindrical piece on my Steyr and Rapid.
The key here, on small diameter pieces is to cut them in ONE Pass!
Then I mount the into the Piston and turn Whole assembly to trim the seal to length!!
The last step is to do a final polish of the Plastic insert!!!!
The key here, on small diameter pieces is to cut them in ONE Pass!
Then I mount the into the Piston and turn Whole assembly to trim the seal to length!!
The last step is to do a final polish of the Plastic insert!!!!
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Have placed PEEK regulator seats within RAW / THEOBEN & NINJA regs many times. Have made flat sealing disks for HuMa regs as well.
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Yes ... These soft insert seats first need to be carefully drilled out a tad smaller than pocket diameter & carefully pulling out whats left.
Then measure pockets I.D. & Depth.
Using a Lathe and material you decide on using, make a stub that generally is @ .001 to .003" larger for a light press fit. Length kept longer by .050" or so.
New seat ( Ideally pressed in evenly Via a small precision vise ) From there the Spool containing the new seat is put back into the Lathe, Run out ( TIR ) fiddled with to get it spinning true & square. The excess length is then cut down where required making sure surface finish is baby butt smooth !!!!
An eye loope or magnifying glass helps here a bunch to note if surface finish is smooth and not a microscopic spiral.
Some polishing can happen by using 1200-1500 wet/dry sand paper used wet with WD-40 held against spinning seat while still in the lathe.
* At least how i go about it
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Just like Motorhead instructed....
The length is not Too important...Just as long it is a bit longer so it can be trimmed .
Trimmed it a couple of thousand above the surface.....
But the tricky part is the diameter of the insert!!!
I have gauge pin set to measure the hole in the piston to the nearest thousandth...
But You can try measure the insert if you can pop it out intact...
I go for about 1 thousandth over for a snug fit....
Good Luck!!!!
The length is not Too important...Just as long it is a bit longer so it can be trimmed .
Trimmed it a couple of thousand above the surface.....
But the tricky part is the diameter of the insert!!!
I have gauge pin set to measure the hole in the piston to the nearest thousandth...
But You can try measure the insert if you can pop it out intact...
I go for about 1 thousandth over for a snug fit....
Good Luck!!!!
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@CA_ Verminter Removing and measuring the disc seems to be the trickiest part. @Motorhead's suggestion is gold in that regard. What can you do if you deform or destroy the piston seat before a good measurement can be taken? I there a way to go about reproducing it based upon the inner diameter of the hollow portion of the piston?
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Trial fit when oversize looking for it "About to fit" and taking .0005 to .001 passes on diameter til you can darn near push the pocket over the stub, but not quite. No measuring required going on the premise of hand fitting rather than by the numbers
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Actually in your case...
The insert is Relatively Large...... So you can Go for a cut Until it fit method....
The inserts used on the Rapids and Steyrs are on about .085 to .100 in diameter....So the One-Cut method is the best way for these little guys...
Because it hard to re-cut such small dia. pieces on the lathe.......
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I've never seen delrin melt.yes, machining is a rabbit hole within the rabbit hole, so to speak... plastic can be tricky, it does melt ... speeds, feeds, and proper tooling as they say
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The EZ way to mess up your machining of any material is a Dull Tool Bit.
I like to use very sharp Cobalt High Speed steel cutting bits!!
I love my Diamond High speed Tool bit holder!!
But Carbide indexable tools work great too!!
No lube or cooling needed....
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My advice would be to first try and find a manual like this, or similar, like Southbend how to run a lathe, but there are many books out there. This one here is a really in depth look at manual lathe machining processes and practices, a great reference manual.
Also safety is a big factor with machine tools, eye protection a must. Also great youtube channels, Tubalcain is one, Stefan Gotteswinter, Keith Fenner are a few of my favorites.
Here are a few tools I have at the ready at my lathe, all set and on center, just swap'em and go.
GROOVING.....left to right
HSS cut off, two inserted cut off tools, two OD groove tools, last one is .034 wide.
TURNING tools... left to right, CCMT .008NR sharp positive rake, aluminum, plastics. CCMT .008NR for hard steels. Left and right 35deg tools with .008NR for steels.
MICRO BORING...solid carbide boring bars for small holes down to under .100" diameter.
Couple more boring bars..micro bars and 1/4" carbide inserted bar far right, that can go fairly deep, bar is 6" long.
45 deg cemented carbide tip tools for breaking edges quickly, and top, a deep cut OD groove inserted, can also part off with this tool, or cut deep grooves on back side of part.
LIVE center and keyless drill chuck for the tail stock. On top a deep ID grooving tool.
These are what I keep ready at my lathe. You will find out tooling is where your money goes when starting out. A 5C collet chuck is one of my most used chucks for fast set ups. 3 jaw and 4 jaw also
needed for certain jobs.
Also safety is a big factor with machine tools, eye protection a must. Also great youtube channels, Tubalcain is one, Stefan Gotteswinter, Keith Fenner are a few of my favorites.
Here are a few tools I have at the ready at my lathe, all set and on center, just swap'em and go.
GROOVING.....left to right
HSS cut off, two inserted cut off tools, two OD groove tools, last one is .034 wide.
TURNING tools... left to right, CCMT .008NR sharp positive rake, aluminum, plastics. CCMT .008NR for hard steels. Left and right 35deg tools with .008NR for steels.
MICRO BORING...solid carbide boring bars for small holes down to under .100" diameter.
Couple more boring bars..micro bars and 1/4" carbide inserted bar far right, that can go fairly deep, bar is 6" long.
45 deg cemented carbide tip tools for breaking edges quickly, and top, a deep cut OD groove inserted, can also part off with this tool, or cut deep grooves on back side of part.
LIVE center and keyless drill chuck for the tail stock. On top a deep ID grooving tool.
These are what I keep ready at my lathe. You will find out tooling is where your money goes when starting out. A 5C collet chuck is one of my most used chucks for fast set ups. 3 jaw and 4 jaw also
needed for certain jobs.
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