Another day in the Dtech shop.

dtech

dtech

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The way I ended up going about this is somewhat backwards, but when I posted the fist "day in the shop" I had no idea there would be more. I received several requests for more info, so here we go:

This is how the barrels come into my shop from Shilen. I may get 2 or three barrels in at a time, or may get 30 or 40, it all depends on their production schedule.
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Now from one of the earlier posts, you may remember a huge batch of barrels that got chambered and were ready to profile. Some of those barrels got threaded, headspaced, profiled fluted and shipped. Even though there are still unfinished barrels from that batch, this batch of blanks that I received contains blanks that I have been out of. What I do then is sort through the order and put the ones I don't need into stock, and start to prepare the needed blanks for a chambering batch.

I just store my excess barrel inventory in racks like this. Recently, most of my barrels are in production, and that's why there are gaps in my storage rack.
DSC_0430_s.jpg


Once I have all of the blanks gathered up that I am going to be working with, I label the barrels with permanent marker with my internal part numbers. The barrel-blanks come stamped from Shilen with twist-rate, caliber and grade, but that end of the barrel gets removed in my preparation for chambering.

The first thing that gets done to the blank is the excess material on the chamber end gets removed.
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Once that material is removed, a precision, concentric cut is made for the first 8 to 10 inches over the chamber end of the barrel.
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After that, the end of the barrel is parted-off, and a cutter is used to make a smooth, square face on the chamber end of the blank.
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The blank is then turned end-for-end in the lathe and a chamfer is cut into the muzzle end of the barrel. This chamfer will later be used to couple my high-pressure flush system to the barrel while chambering.
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After those steps, the new blanks are now ready for the next chambering batch, and the whole cycle starts over again!

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In all honesty, what I have posted is not 100% accurate as to the procedures I go through to prepare the blanks. I have left out a few minor details and twists just in attempt not to show certain tooling or procedures. If some of you real gun-nuts or metal-heads see some anomalies in this post, that is why.
 
There is tons of work in those barrels. I never realized how much... You got a good process Mike. Can't wait to catch my name on one of those barrels...Jason
 
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Looking good. A guy can`t let out all of his secrets !!
Couple of questions if you have time;
I have not decided what type of coolant to use in my new lathe, so what do you use? I have been considering Cimcool (I think thats the stuff, in pink can).
I have had the Lathe for awhile and just been using a cool-tool with water based Hydra-Cut.(don`t care for the residue it leaves.
The other question, a guy asked me how do they spiral flute a barrel, and I replied my `guess` would be with a 5th axis (indexer)on a CNC mill and a BN end mill??
After looking at pictures of the bolt Tim N. posted I`m not sure. Always seems like several ways to go about a task in the shop.
Thanks for sharing.
 
Hooked, the spiral fluting is produced just as you suspected, however it can be done on a standard knee-mill with a dividing-head coupled to the longitudinal or "X" axis drive. As the X axis progresses, the barrel, held by the dividing-head, is rotated in proportion to the X axis, and a spiral flute is the result.

believe it or not, I run solid carbide tooling and no coolant. I have Shilen take the blanks down to just a little over an inch, except for that small area on the chamber end. In doing it that way, I can make pretty much make anything out of a blank, and don't have to remove enough matal to heat the blank while I work.

When I take that knob off of the chamber end of the blank, it does get warm, but not hot. That part of the process creates more heat than any other part of the process.

Shilen ships their blanks two ways: 1) raw 1.250" diameter blank. 2) or profiled. The profiled blanks are much more expensive, and limit you as to what can be done with them. When I started doing business with Shilen, I asked about getting this "contour" to save me from running coolant, save the cost of shipping the heavy blanks and to alow me more latitude in what could be produced with the blanks. Shilen lovingly refers to this profile as the "no flip dog". This contour costs a fraction of a standard profile because I agreed to leaving that knob on the end of the barrel. They grab the barrel-blank in a CNC lathe and rough it down under a flood coolant. The area where they hold the barrel can't be machined, hence the "knob". The fact that they save time by not having to "flip" the barrel, grab it by the other end and machine away the knob, spawned the name "no flip dog".

Shilen has been fantastic to work with, this special contour is just one example of that fact. By my request, they have produced two different caliber/twist combinations that had not been available in there line-up. Not every barrel maker will do that.
 
Thanks for allowing us to watch Mike. So much for venturing into a hobby for after retirement! Better watch it, the next thing you know, you'll be making "hobby" videos. Take care, and as everyone else, looking forward to your next shop pictures post.
 
Thanks for the reply Mike. I imagined there must be a more conventional way to cut flutes w/ a knee mill.
I believe it about not using coolant w/carbide, and actually according to a Kennametal Seminar I attended years ago, the engineers said if you can`t keep it flooded then don`t use it (coolant).I have good results with this Kool-Mist coolant device (siphon coolant out of sm.bottle). The guys before me had oil in the coolant tank, and that was a stinkin` mess.I only use oil for tapping/cutting threads.
I`m sure Shilen is proud of how them `no flip dogs` finish their journey!
Take care!
 
Dtech too bad you live in MN. I would really like to know how to learn how to chamber a rifle. I have a lathe and the normal lathe tools. Endmills, several different turning tools,parting tools and the such. But I do not have any reamers/holders YET. I would really like to do this someday if I ever get over of thinking about turning/cutting on a $300 barrel. Not to hi-jack the thread but do you use the lambreth/Kiff reamer stop tool ? Thanks
 
cyotekler, "Chambering" a barrel is really no big deal. Chambering a barrel so that it will be accurate is more difficult. Chambering a barrel so that it will be accurate, and getting it done in a time-frame that you can make money on is WAY more difficult. I have invested in some pretty expensive tooling to cut time off of my chambering duties, and still give me the accuracy I demand.

I purchased the Lambreth/Kiff reamer-stop system, but never ended up using it for my operation. The reason is simple: If you look at the way I prepare the blanks, you will see they are just raw cylindrical tubes. No threads or profile yet. I use a high-pressure flush system while chambering, and have found that it is much easier to get a great chamber if you are not concerned over the depth of the chamber. What I do is pay VERY close attention to making sure the reamer is clear of chips, and I get a real good, smooth chamber. After that, I drop a head-space gauge into the chamber and decide how much of the barrel-shank needs to be trimmed off in order for the chamber to be the correct depth. Then I thread the shank and add the barrel-extension.

That is the real reason I never put the reamer-stop to use. I simply watch the digital read-out to make sure I'm deep enough, and concentrate on finishing with a smooth chamber.
 


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