Machining a booster

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cdhknives
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Machining a booster

Post by cdhknives »

I am looking at some of the commercially available boosters, such as Liberty and SD, and failing to see how I can build one with only a lathe. If the splines on the internals are required I can't see how to build it without a mill, and I don't have a mill. Am I over-complicating this? Should I just spend the $100 even though it will not blend well with my form 1 build?
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partsguy22
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Re: Machining a booster

Post by partsguy22 »

Creative work holding

hold the work on the cross slide and end mill in the chuck and just like that its a horizontal mill

ETA

or you can adopt an inexpensive CNC spindle to use as live tooling

or even use it to broach splines
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Re: Machining a booster

Post by daviscustom »

partsguy22 wrote:Creative work holding

hold the work on the cross slide and end mill in the chuck and just like that its a horizontal mill

ETA

or you can adopt an inexpensive CNC spindle to use as live tooling

or even use it to broach splines

When you say "Inexpensive CNC spindle" what are you talking about $wise? .....and where can they be acquired?

I built a holder for a 1/4" trim router that allows me to mount it to my tool post, and that allows me to do quite a bit. I think it would be better if it was a larger (read more rigid) mount that replaced the tool post altogether for milling operations.
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partsguy22
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Re: Machining a booster

Post by partsguy22 »

it depends on how much muchness you want but

a 500w spindle can be had for less than $100
a 1.5kw will run around $300
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Re: Machining a booster

Post by T-Rex »

Read this build. In it I explain all about a live tool. I even show an inexpensive way to index the spindle/chuck.
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Re: Machining a booster

Post by Historian »

<< https://www.shars.com/catalogsearch/res ... ill+holder >>

I mount my end mills with the above 2MT holder in lathe spindle.
DO NOT hold end mill with 3 or 4 jaw chuck ... at best it will slip,
at worse ...gasp. :)

For my Atlas 618 I use the antiquated but still useful milling attachment.
e.g., << https://www.ebay.com/itm/NOS-ORIGINAL-A ... :rk:1:pf:0 >>

There are many YouTube videos of making your own heavy duty milling attachments that
fit firmly on cross slide.

Fun 'beating the system'.

Best.
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Re: Machining a booster

Post by partsguy22 »

I mount my end mills with the above 2MT holder in lathe spindle.
DO NOT hold end mill with 3 or 4 jaw chuck ... at best it will slip,
at worse ...gasp. :)
...
Fun 'beating the system'.

Best.
I agree however my lathe has a 6mt spindle
So I use an er40 collet chuck
I have also used a collet block held in a 4 jaw in a pinch
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Re: Machining a booster

Post by cdhknives »

I have 1/16" increment 3C collets through 9/16" for holding endmills and appropriate size of rod stock. There is a 60 pin indexing ring in the bull gear of these Atlas lathes and I could rig a very slow linear cut with the carriage feed and eventually make the male spline or rig something with the QCTP to hold the piston. The internal grooves for the spline to ride are the bugaboo. I assume a broach or make them in pieces on a mill is the 'correct' way. Neither is in my bag of tricks.

Does the spline just keep the tube from rotating? Why do I care in a home build if I cut wrench flats in the piston?
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fishman
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Re: Machining a booster

Post by fishman »

I'm also curious about why/if the spline is necessary
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Re: Machining a booster

Post by T-Rex »

This is how I've made them. There's no internal grooving and all milling is done perpendicular to axis of bore or lathe spindle. There are a good number of cuts, but the material is thin and they go quick.


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Re: Machining a booster

Post by cdhknives »

So the tips of the male spline rides on a smooth interior, not in a groove? I assume that means it is only a vent, not something intended to prevent rotation or maintain alignment?
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Re: Machining a booster

Post by T-Rex »

cdhknives wrote:So the tips of the male spline rides on a smooth interior, not in a groove? I assume that means it is only a vent, not something intended to prevent rotation or maintain alignment?
No, they don't "ride" on anything but the ID of the housing.
They do, however, prevent rotation once the piston is fully seated.
This is what the smaller, OD, milled slots are for.

The larger slots, in the piston and housing, allow the volume to be used as a blast chamber.


Maybe this details it a bit better.


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Re: Machining a booster

Post by ECCO Machine »

cdhknives wrote:So the tips of the male spline rides on a smooth interior, not in a groove? I assume that means it is only a vent, not something intended to prevent rotation or maintain alignment?
The drilled holes creating notches serve to prevent the piston from rotating when it's seated so you can rotate the can to remove & install. The pistons don't typically rotate during firing, piston "teeth" will fall back into the notches.

I personally feel the the more or less "standard" piston design lacks sufficient bearing surface, so took a different approach with my boosters & pistons (which can use SilencerCo pattern pistons as well). Instead of drilling a bunch of little holes to create slots that engage the piston teeth, I make a separate weld-in piece that has a single lug on it which can engage between the lugs of my tri-lug pistons or the teeth of SiCo pattern stuff.

Image

Image

Image

The housing is not a through bore of 1" ID; there is an internal shoulder that the welded in lug ring seats against.
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Re: Machining a booster

Post by Capt. Link. »

cdhknives wrote:I am looking at some of the commercially available boosters, such as Liberty and SD, and failing to see how I can build one with only a lathe. If the splines on the internals are required I can't see how to build it without a mill, and I don't have a mill. Am I over-complicating this? Should I just spend the $100 even though it will not blend well with my form 1 build?
You can cut slots with a lathe by indexing the head and using a boring bar w/ a shaper tool. You just use the lathe as a manual shaper no clapper box needed.You could also drill a ring of indexed holes and bore out 80% of the hole leaving radius cuts inside.You could also buy a broach and cut slots in the traditional manner.
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Re: Machining a booster

Post by cdhknives »

partsguy22 wrote:it depends on how much muchness you want but

a 500w spindle can be had for less than $100
a 1.5kw will run around $300
You are referring to something like this?

https://www.amazon.com/Konmison-Cooled- ... ndle+motor
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T-Rex
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Re: Machining a booster

Post by T-Rex »

cdhknives wrote:You are referring to something like this?
https://www.amazon.com/Konmison-Cooled- ... ndle+motor
If you can swing it, I'd go for something 1.5kw or greater.
I got the 2.2kw, water cooled kit.
It's 220v so I had to run another feed to the shop.

I'll try to remember and take some pics of the VFD's and user control panel I made.
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Re: Machining a booster

Post by T-Rex »

Sorry, didn't realize how blurry the pic was until it was uploaded. You get the point.
Black drive is for lathe motor and grey one is for the CNC spindle.

Image


Control panel I made.

Image

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cdhknives
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Re: Machining a booster

Post by cdhknives »

T-Rex wrote:
cdhknives wrote:You are referring to something like this?
https://www.amazon.com/Konmison-Cooled- ... ndle+motor
If you can swing it, I'd go for something 1.5kw or greater.
I got the 2.2kw, water cooled kit.
It's 220v so I had to run another feed to the shop.

I'll try to remember and take some pics of the VFD's and user control panel I made.
That would be 3x the horsepower of my lathe motor! Air cooled has serious advantages but I wonder about the lightweight small units holding tolernaces. They do not have good accuracy ratings and advertise as for engraving machines...not the same as cutting 17-4 or grade 5 titanium.
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