GTA
All Springer/NP/PCP Air Gun Discussion General => Machine Shop Talk & AG Parts Machining => Topic started by: Mike71 on March 11, 2025, 01:13:48 AM
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I've thought about this for years, time to actually make it.
I'm wanting a small 3 jaw chuck mounted on a shaft and supported by 2 piller block bearings, gear-sprocket-pully drive and a 12v electric motor, pwm speed controller.
Basically a mini lathe head without the bed.
Just to hold and spin parts while I work on them.
I can build it all less the shaft to mount the chuck.
For the people who know, what threads does a small (4") chuck take ?
Can I get someone to turn me a shaft and I do the rest ?
Spitball me some ideas while I go look up a chuck, I'd think a round rubber belt would be best to drive it with as it will give some cushion from any shock, and be as quiet as can be. I have the motor and pwm controller now.
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Doesn't say how it's mounted, but if it has a though hole it has to be a flange type, I'll contact the seller to ask, but this is about what I'm talking about, may even for with a smaller 3"..
https://www.ebay.com/itm/156649869425?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=OhNwWMooR_q&sssrc=4429486&ssuid=j2mz6nWtQTW&var=&widget_ver=artemis&media=COPY
Something close to this, with a pully on the back and Not $300 like this one is.
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A lot of the chucks simply bolt to a faceplate. There are some lathes that have a threaded spindle but are generally geared more to older lathes and woodworking chucks. That’s just my experience.
The picture below is for a harbor freight mini lathe, 3” face. It is such a common lathe, many parts are available at a reasonable price. The shaft will accept a common bearing size.
Dave
https://littlemachineshop.com/products/search.php?First=7&Last=31&Model=93212&tabName=Parts
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I was looking at the bigger 1/2 drill chucks that take a 1/2×20 thread, but I really would like to be able to chuck up on larger tubes from the inner diameter.
I may need to get a shaft made depending on how far apart the bearings need to be spaced and still have room out back for a pully.
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So the shaft I pictured above is NOT what you are looking for?
Dave
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If you search Amazon for small 3 jaw chuck you will see a lot of options with the 1"-8 thread mount used on wood lathes and many of them include an arbor.
But machining a tube with just shallow, single ended support can get pretty risky. Not sure what you are trying to do.
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Yes that shaft would be right if it's long enough, may have to turn the very end down to fit the pully, I'm looking at those right now.
I just need to hold and spin shafts or small tubes to use a file or Dremel tool by hand to for the most part true up and trim down like I have been in my cordless drill making crosman hammer pins and the likes. A 1/2 drill chuck would work for 75-80% of all I do, but would like to make a tube spacer from time to time.
Trust me I miss all my shop tools (22" lathe, mill, tig welder) and I'd love to get a small cheap table top lathe, but $700 is more than I can do and I don't have a place to put it.
So a homemade powered chuck is all I need right now.
Let me find a chuck and go from there for now. Mostly coming up with ideas and picking the best easiest to mount chuck. May or may not need to make/modify an arbor shaft.
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Been doing it like this. Piston link pin.
Hammer pin.
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There also spindle assemblies. No clue on quality.
https://www.amazon.com/s?k=B0DFY5HHFD
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And amazon.com/dp/B0DQ4PC46S?th=1
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Yes that shaft would be right if it's long enough, may have to turn the very end down to fit the pully, I'm looking at those right now.
I just need to hold and spin shafts or small tubes to use a file or Dremel tool by hand to for the most part true up and trim down like I have been in my cordless drill making crosman hammer pins and the likes. A 1/2 drill chuck would work for 75-80% of all I do, but would like to make a tube spacer from time to time.
Trust me I miss all my shop tools (22" lathe, mill, tig welder) and I'd love to get a small cheap table top lathe, but $700 is more than I can do and I don't have a place to put it.
So a homemade powered chuck is all I need right now.
Let me find a chuck and go from there for now. Mostly coming up with ideas and picking the best easiest to mount chuck. May or may not need to make/modify an arbor shaft.
The pulley could be mounted in the center of shaft, between the bearings if needed.
Almost sounds like a small/cheap wood lathe would work for you….
Dave
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Been doing it like this. Piston link pin.
Hammer pin.
Just curious--how much material are you removing (typically) using this method? Also, are you getting adequate concentricity, with no appreciable taper in your pins doing it like this? I would think achieving these parameters would be somewhat difficult doing it by hand, unless only removing a few thousandths or so. Looking good is one thing, actually being good is another. I guess it depends on the part's intended usage that determines the degree of precision needed. I DO appreciate the amount of labor/time it takes to do something like this entirely by hand.
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Link pins can very from one end to another, but I start with a shaft just a bit bigger, use my calipers often and also test fit often.
The hammer pin isn't that difficult, just make it barley on the large size and them sand till it just does fit..
Also I've been a welder/fitter/machinist for many years, artists in my right thumb is from holding small parts while fileing the last bit for a perfect fit.
The amount taken off ? I try and start with a shaft as close as I can, grinder takes care of the most, Dremel then file..
If I still had my mill and lathe I would do better. But this is what I have now..
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I have a "paper" design for a large turning head using a 2.5" OD steel pipe (hollow) shaft, 2.5" ball bearing pillow blocks, belt-driven pulleys and a VFD controlled 3phase motor (2HP).
I currently have all the parts I need to start the project. Just don't have the TIME yet.
For NOW I purchased this chuck and a threaded adapter to use on my small Grizzly wood lathe.
www.amazon.com/dp/B09VBJ1DJK
www.amazon.com/dp/B09K3GNST2
It's not much, but between a 3/4" Jacobs chuck (MT2 taper?) I had that fit the lathe and the items above I've been able to make/repair poppets and create some custom HPA fill probes.
NOT airgun related but I also used the large chuck to turn a couple 2.5" diameter UHMWPE piston heads with o-ring grooves (and some with cup seal grooves) to repair some impossible to replace SS air cylinders for the brewery I work for. That repair has worked very well ... after I corrected a small miscalculation (my fault) regarding the different thermal expansion coefficients of SS verses UHMWPE (ooops ;-)
It is surprising what you can make with a spinning chuck, a sharp gouge, hand-files, dremel cutoff disks, emery cloth, calipers, patience, AND TIME.
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This LW barrel was turned down to 7/16th with a hand drill and file basically, OD specs out better than OE Crosman barrel, and it stayed shinny even after being left out in the rain overnight. :o
(https://www.gatewaytoairguns.org/GTA/gallery/albums/Back_Roads_Basement/Dir_1/main_8479.jpg)