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Gunsmithing lathe spider chuck

300sniper

300sniper

Gunny Sergeant
Full Member
Minuteman
Jan 17, 2005
3,438
26
Greenwood, Ca
#1
i can't remember what forum i saw one of these on, maybe benchrest central. i have been wanting to make one for a while now but it has been on the back burner. now i need to work on a 20" barrel and it is too short to do through the spindle with my 4 jaw chuck.

i ordered an 8" d1-4 backing plate since the 6" was back ordered. i started with a piece of 1" a-35 plate to make the spider because it was cheap. i used (4) 1/2-20 socket head cap screws to attach the spider to the backing plate and (4) 1/2-20 shcs for the "jaws". i did a deep countersink for the adjusters to make sure the heads stay bellow the outer diameter of the spider for safety.

this spider chuck saves me a little bit over 2-1/4" from my 4 jaw chuck. with this set up you need to use the rear spider to support the back side of the barrel. i don't plan on using it for any heavy cuts, just through the headstock barrel work. i'll find out how it works tomorrow.

lathespiderchuck1.jpg


lathespiderchuck4.jpg


lathespiderchuck7.jpg


lathespiderchuck16.jpg


lathespiderchuck12.jpg


i'm going to try using 3/8 copper pipe caps between the adjuster screws and the barrel. they are cheap and will be easy. i have another idea but it will be a lot of work so i want to try these first.

lathespiderchuck18.jpg
 
#3
Re: lathe spider chuck

You can also build a receiver truing collar/sleeve and thread it to screw onto the tennon of the barrel. 1.062” on one end and 1.072” on the other. The outboard spider catches the extension at that point making it possible to cut & crown 21" and shorter barrels if you need to.

Nice job BTW, it should work great.
 
#4
Re: lathe spider chuck

that would work good if i had the barrel separate from the action. i didn't want to remove the action to thread this barrel. any shorter than 20", i will have to remove the action and use your method or use a steady rest.
 
#5
Re: lathe spider chuck

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 300sniper</div><div class="ubbcode-body">that would work good if i had the barrel separate from the action. i didn't want to remove the action to thread this barrel. any shorter than 20", i will have to remove the action and use your method or use a steady rest. </div></div>

Your on the right track. I'd rather take an ass whipping than use a steady rest although thats the only way I know to true a rifle bolt.
 
#11
Re: lathe spider chuck

well it worked slick as can be. dialing it in was much easier with the 20tpi threads vs. what ever is on my standard 4 jaw. i also really liked using the 3/8 copper pipe caps on the screws. i put two #10 flat washers inside of each cap. i was hoping this would allow the screw to turn inside of the cap instead of the copper cap trying to turn on the barrel. it worked as planned. this barrel was about 19" from the recoil lug to the muzzle and i had plenty of room to work. any shorter than that and i'll pull the receiver and go with the method wnroscoe mentioned earlier.

plenty of room.

barrelthread1.jpg


barrelthread3.jpg


and all finished up with a thread protector.

barrelthread5.jpg
 
#15
Re: lathe spider chuck

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DebosDave</div><div class="ubbcode-body">Very nice work! Love the freedom that building your own tooling can bring. Very good solution to a common issue

Dave </div></div>

nothing like spending 2-1/2 days chasing parts and making a tool just so you can do an hour and half long project
grin.gif



another benefit of this is the fact there are no protruding chuck jaws to hit you knuckles or grab your file and fling it across the shop. i think it is far safer than a 4 jaw, especially when working so close to it.
 
#16
Re: lathe spider chuck

First off, very nice work.

I like the idea of the copper caps. I have been drilling the adjusters out and tapping them for copper screws. This is much easier and less likely to mar the finish.

Amazingly enough, around here there are no socket head bolts in 1/2-20 to be had (for a different project.. Guess the oilpatch is not in to fine threads. I am going to improvise with some threaded rod and nuts.

BTW, I went the easy route and bought my spider chuck from Grizzly.
wink.gif
 
#18
Re: lathe spider chuck

300sniper,
First off, I look forward to each of your posts. I just started taking maching classes at my local community college and I always love your pictures and descriptions. You are truly an inspiration.

Second, can you please explain what your pictures are showing from picture 1 through 4? I see things happening, but to the uneducated (yea, that is me), it is not clear what is going on.
Thanks.

Tim
 
#20
Re: lathe spider chuck

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: masterg</div><div class="ubbcode-body">300sniper,
First off, I look forward to each of your posts. I just started taking maching classes at my local community college and I always love your pictures and descriptions. You are truly an inspiration.

Second, can you please explain what your pictures are showing from picture 1 through 4? I see things happening, but to the uneducated (yea, that is me), it is not clear what is going on.
Thanks.

Tim </div></div>

i am teaching myself machining so some of the things i do may be ass backwards compared to what an experienced machinist would do.

here is what i did:

the d1-4 backing plate had a .2" pilot on it to align a standard chuck. i needed my set up to be as short as possible. since i didn't plan on making any heavy or interrupted cuts with this, i felt it was safe to remove the pilot. i also faced the backing plate true to my spindle. at the same time, i put a reference mark on the backing plate so i could insert it into the spindle the same way each time.

lathespiderchuck3.jpg


lathespiderchuck4.jpg


next i took the 1" a-36 plate and faced the top of it so it would have a nice, flat mating surface against the backing plate. then i machined a circle out of the plate. i cut all but about .2" of the depth because i couldn't think of a good way to hold the part when cutting all the way though. i removed the part from the mill and cut the part free from the stock in the vertical bandsaw.

lathespiderchuck1.jpg


lathespiderchuck2.jpg
 
#21
Re: lathe spider chuck

next i clamped the backing plate on the mill and found the center. i spaced it off the table with some 123 blocks since i would be drilling all the way though it.

lathespiderchuck6.jpg


then i drilled and tapped 1/2-20 holes that will be used to hold the chuck portion to the backing plate.

lathespiderchuck7.jpg


while it was still set up, i clamped the chuck portion to the backing plate and drilled, counter bored and chamfered the holes for the 1/2-20 socket head cap screws.

lathespiderchuck8.jpg


i bolted the chuck portion to the backing plate and removed the clamps. i had planned on facing the chuck portion and finishing the diameter of it on the mill but my clamps were in the way. no big deals as finishing it on the lathe would ensure it is true to the spindle.

lathespiderchuck9.jpg


while finishing up the diameter and facing the chuck portion, i also bored out the inside hole.

lathespiderchuck11.jpg
 
#22
Re: lathe spider chuck

next i place the assembly in the mill's 4th axis and drilled, tapped and counterbored the 4 holes for 1/2-20 shcs used as the chuck "jaws".

lathespiderchuck15.jpg


that about completed the project. this is the chuck in use while turning down the shank for threading a barrel.
barrelthread4.jpg
 
#25
Re: lathe spider chuck

after 3 years of use, a stepper drive went out on my mill the other day. i replaced it and needed a project to give me a bit of confidence it is working fine again.

i had been wanting to engrave degree marks around the spider chuck to help with timing muzzle brakes and timing barrels to receivers. this project had never been priority so i had been putting it off. i knew this would take a couple hours of non-stop machining and use all three axis' of the mill. it was also not a critical part so i wouldn't cry if the mill happened to go down while running it. sounded like a perfect time to take care of this. the machine ran flawlessly for 2-1/2 hours so i think i can trust it again.

spiderchuckengrave1.jpg


spiderchuckengrave2.jpg


spiderchuckengrave3.jpg


spiderchuckengrave4.jpg


spiderchuckengrave5.jpg


spiderchuckengrave6.jpg
 
#28
Re: lathe spider chuck

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 308JEFF</div><div class="ubbcode-body">Excellent work dude, where does one start when trying to learn how to do these kinds of thing? </div></div>

i am teaching myself by reading and doing (and buying new tools when i do wrong). finding a school to teach you would probably be a faster way to go about it though.
 
#29
Re: lathe spider chuck

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 308JEFF</div><div class="ubbcode-body">Excellent work dude, where does one start when trying to learn how to do these kinds of thing? </div></div>

Find a local smith and ask if you can come by once in a while and clean the shop wipe down the equipment and occasional look over his shoulder. If you do well he may even let you ask a question but only one.The number one rule is eyes and ears open and mouth shut.If you cant find a smith go to a machine shop. Mill and lathe operation can be learned sans firearms.
 
#30
Re: lathe spider chuck

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 300sniper</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 308JEFF</div><div class="ubbcode-body">Excellent work dude, where does one start when trying to learn how to do these kinds of thing? </div></div>

i am teaching myself by reading and doing (and buying new tools when i do wrong). finding a school to teach you would probably be a faster way to go about it though. </div></div>

Any Recommended reading material out there? I wish there were gunsmiths out here in hawaii (competent ones anyway). All of our gunsmithing work usually get sent out to the mainland.
frown.gif
 
#31
Re: lathe spider chuck

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 308JEFF</div><div class="ubbcode-body">
Any Recommended reading material out there? I wish there were gunsmiths out here in hawaii (competent ones anyway). All of our gunsmithing work usually get sent out to the mainland.
frown.gif
</div></div>

here and the gunsmithing forums at benchrest central and practical machinist are good places to read. i feel it is best to read as many posts by as many people as you can and try to come up with methods that make the most sense to you. don't take any method as the only way to do something. make sure you understand why you do something the way you do. there are a few ways to do rifle work and i am not sure if any one way is the perfect way.
 
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