Need Advice on a New Chuck

1.375" OD x 0.035" Wall x 1.305" ID Stainless Round Tube 304 Seamless

1.5" OD x 0.035" Wall x 1.43" ID Stainless Round Tube 304 Seamless

Yeah thats fairly thin :) and in stainless steel too. Double the fun.

I would make a mandrill for the work to be glued onto , being stainless you can't really take the risk of rubbing the tool and work hardening it if your trying to take small bites at it to avoid deforming the part with tool pressure alone. At least with a mandrill of sacraficial material you can work it like it was a solid bar.

If your doing the I.D. also you would need to make some sort of reverse mandrill or pot chuck.

Glue like Cyno Acrylic (super glue) should brake lose with very little application of heat so you wont have to destroy the part fitting it to and removing it from mandrills.

Stu
 
Looks good, as it stands the finish on your work is chattery.
Dial your speed down a bit
 
Are you using inserts or hss?
I use inserts for aluminium that have a positive rake and are very sharp.
Works great for finishing ss.
 
Are you using inserts or hss?
I use inserts for aluminium that have a positive rake and are very sharp.
Works great for finishing ss.
I am using carbide insert tools. My parting tool, turning tool, and all of my boring bars (many different sizes) are all carbide inserts. I haven't tried HSS yet. I really need to take a day and learn about tooling, and more specifically, how the angles and "rakes" affect the overall machining experience.

I am still super green with all of this stuff. I'm kinda surprised I've been able to actually make some usable parts since I first plugged this thing in almost 3 months ago!

I wanted a metal lathe because I am somewhat of an amateur gunsmith. I very much enjoy building my own form-1s, which I can only imagine how many machinists on this forum have or at one point had the same intentions. They are a blast to make! This is the first one I completed on my Grizzly. I finished it a few days ago. The cones are 7075, and the tube and end caps are 6061.

my-cone-2.jpg

This cone size is a little larger (1.145" OD), and will be for .223/556 supers. This is a tiny bit smaller than the more standard size of 1.5" OD / 1.355" ID or 1.372" ID. I chose this size because as many of you know, typical free-floating MLOK handguards have an interior diameter of (roughly) 1.35". So, unless you feel like doing some major modifications to a brand new handguard (I've done this way too many times!), the next logical application would be to build something that will just barely fit inside of most handguards. This way I can recess the can as far back into the rail as I want. This will most likely live on a standard carbine with a 16" barrel. Length will be 7.5".

The metal is pitted like that because my dumb ass decided to clean it up with a wire brush in my drill press. :(

my-cone-1.jpg
 
Another option may be to purchase a 5C hex collet block as in this set:


and then buy the appropriate size 5C collets for the tubing you are working with. The hex block can be mounted in a 3 jaw chuck or the square block can be mounted in a 4 jaw chuck. The collets will provide good support for your tubing. Just some food for thought.

Ted
This is the way I would suggest you go.
You will be able to hold work without damage and there must be a hundred of choices for 5c collets, depending on diameter, shape and collet accuracy.
 
I am using carbide insert tools. My parting tool, turning tool, and all of my boring bars (many different sizes) are all carbide inserts. I haven't tried HSS yet. I really need to take a day and learn about tooling, and more specifically, how the angles and "rakes" affect the overall machining experience.

I am still super green with all of this stuff. I'm kinda surprised I've been able to actually make some usable parts since I first plugged this thing in almost 3 months ago!

I wanted a metal lathe because I am somewhat of an amateur gunsmith. I very much enjoy building my own form-1s, which I can only imagine how many machinists on this forum have or at one point had the same intentions. They are a blast to make! This is the first one I completed on my Grizzly. I finished it a few days ago. The cones are 7075, and the tube and end caps are 6061.

View attachment 355224

This cone size is a little larger (1.145" OD), and will be for .223/556 supers. This is a tiny bit smaller than the more standard size of 1.5" OD / 1.355" ID or 1.372" ID. I chose this size because as many of you know, typical free-floating MLOK handguards have an interior diameter of (roughly) 1.35". So, unless you feel like doing some major modifications to a brand new handguard (I've done this way too many times!), the next logical application would be to build something that will just barely fit inside of most handguards. This way I can recess the can as far back into the rail as I want. This will most likely live on a standard carbine with a 16" barrel. Length will be 7.5".

The metal is pitted like that because my dumb ass decided to clean it up with a wire brush in my drill press. :(

View attachment 355225
Your work is pretty good for someone green.
Like you I use mostly insert tools but also hss for form tools, such as for forming a radius or a particular shape in a recess where a normal boring bar cant fit.
Over time you will come to the conclusion that there is a relationship between the feedrate and the radius of your tool at the cutting edge. This impacts the finish of the completed product, so you don't have to do much rework to make things look prettier. This is important both when power feeding and more so when hand feeding on surfaces such as tapers.
If you want to polish surfaces use an emery tape with some lube, i find this more efficient than wire brushes and there is no metal transfer from brush to work in the case of dissimilar metals, particularly when machining stainless steel. I envy your ability to be able to make form ones. Can't do it in my country due to the wankers in power.
Keep up the good work.
 
This is the way I would suggest you go.
You will be able to hold work without damage and there must be a hundred of choices for 5c collets, depending on diameter, shape and collet accuracy.

the 6-jaw chuck allows me to clamp down as hard as I want on thin-walled tubing and it doesn't deform the workpiece at all, besides some minor surface scratching where the jaws contact the metal.
 
Your work is pretty good for someone green.
Like you I use mostly insert tools but also hss for form tools, such as for forming a radius or a particular shape in a recess where a normal boring bar cant fit.
Over time you will come to the conclusion that there is a relationship between the feedrate and the radius of your tool at the cutting edge. This impacts the finish of the completed product, so you don't have to do much rework to make things look prettier. This is important both when power feeding and more so when hand feeding on surfaces such as tapers.
If you want to polish surfaces use an emery tape with some lube, i find this more efficient than wire brushes and there is no metal transfer from brush to work in the case of dissimilar metals, particularly when machining stainless steel. I envy your ability to be able to make form ones. Can't do it in my country due to the wankers in power.
Keep up the good work.
Thanks! I appreciate the advice. I have noticed that my lathe is still cutting a slight taper when I am turning round tube. I have checked to make sure that the lathe is level, which it is. I checked this using some 1-2-3 blocks and a $200 machinists level. Gibs have been tightened and the machine is working great, other than that stupid taper. Basically, my cut gets deeper (when turning outside) as I move my cutting tool closer to the chuck. Could this be happening because I am not using a follow rest?
 
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