# Chassis Build



## jbolt

This will be a build log for a tactical rifle chassis build. I figure since most of the manufacturing will be done on my CNC converted PM-932 I would post it in the CNC forum.

This is the CAD model I did in Solidworks. The chassis is loosely based on the Remington MSR. This is setup for a Rem 700 short action receiver.






I started with the easiest parts, the butt pad mount and slide.

The mount has ops on both sides so those were done in the vise. The perimeter was done by bolting it to a fixture held in the vise. The slide was drilled then bolted on the same fixture to do the perimeter and dovetail.

Tool paths in HSM Express.



Completed slide on fixture.




Completed mount and slide.





The parts get more complicated from here so figuring out the work holding will be a challenge.


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## Metal

ooh neat looking, is this an "only for me" project or will you eventually make the file avail?


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## jbolt

Metal said:


> ooh neat looking, is this an "only for me" project or will you eventually make the file avail?


We'll see how it comes out first.   This is the 5th revision just in CAD. The final version may have some changes depending on how the parts come out or difficulty in machining.


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## Randall Marx

Looks like fun...will be watching for progress!


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## jbolt

I got the stock pivot block done today. I tried to take a time laps video but the lighting on the mill washes out the image and the flood coolant doesn't help. I'll try with the lights off on the next part.

I had a couple of hiccups. When I first designed the part I had the corner screw holes and counter bores too close to the edge. I moved them in but did not catch that the 1/4" spot drill would rub the side so it left a mark. The other issue was I made the rough stock a little too large in one direction and it cut one of the round overs a little too deep. Those are minor blemishes that will be hidden in the pivot well of the stock plus I will be painting everything so it can be fixed without remaking the part.

The part took 11 different tools over 5 separate setups. Total machining time was about 50 minutes including setup changes.

Part in CAD, with tool paths and finished.


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## countryguy

AWESOME!!! My Kid is going to flip.  He's a few years away from this level of competence but hopes to be able to do things like this.   What material are you using for the parts?  Mix of metals?  Alu... any Alloys or Titanium (teasing) to come.   Will be watching Sir! 

Thanks for the build post. 
JJ


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## Billh50

Very nice looking. I watched a build before on a mosin nagant that looked incredible. I was wishing he would have released his plans but he didn't. I have a mosin that someone had cut down a bit and would have loved to make something like he did. I think your build will be even more intriguing to many. Good Luck with the build.


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## jbolt

Thanks JJ & Bill!

Next part is the butt stock. 13 tools, 7 setups, 22 tool paths, plus 1 fixture. The first 5 setups were done in the vise including the top, front, rear, left and right sides. The last 2 setups were done on a fixture held in the vise. These were the right and left contours and corner rounding. The corner rounding was done in a 3D tool-path with a 3/16" ball end mill. The corner rounds took 21 passes to complete. The fixture was setup to be able to flip the part and use the same work offset. The part was held to the fixture with two 8-32 screws through the clearance holes in the part and a plate at the front that used the already drilled holes for mounting the pivot block. I still need to do the narrow slits in the top and rear but I need to get a smaller slitting blade and arbor. Overall I am very pleased with how this came out considering all the different setups and I managed not to to screw up a tool path.

Tooling




CAD and CAM







Completed part



Completed part with Pivot block attached.


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## dieselshadow

Very impressive sir!


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## jbolt

Here is part 1 of several showing the machining of the butt stock. I'm still getting used to this camera. It seems to stop recording after 48 minutes and has to be restarted so I missed some operations. I'm no video editor so these are just the raw footage speed up 16x.


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## 09kevin

Hi Jay. Nice looking parts! 

Kevin


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## jbolt

Thanks Kevin!

Two more videos capture the majority of the machining process. Sorry for the dead spot in video 2 as I got called away and am too lazy to edit it out.


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## bpratl

Jay, that is some very impressive design, setup and machining. Bob


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## jbolt

Thanks Bob!

Rats my lathe delivery was put off unit tomorrow so I had some time to run another part. This is the hand grip mount. The grip is an AR-15 type.

This was a fun part to do. Just modeling the part challenged my feeble knowledge of Solidworks and then came the CAM. I tried some new 3D strategies and it worked out well.





This part took 5 setups, 11 tools and 31 tool paths.


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## Sendit

Hello. The recoil pad how did you go about modeling it/measuring to get the profile so perfect ?


Sent from my iPhone using Tapatalk


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## 09kevin

Looks good Jay! I noticed that you were playing with the 4th axis in another post, have thought about using it on some of these parts?

Kevin


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## jbolt

Sendit said:


> Hello. The recoil pad how did you go about modeling it/measuring to get the profile so perfect ?
> 
> 
> Sent from my iPhone using Tapatalk



I traced the base of the recoil pad, scanned it to a bitmap file and then imported it into Solidworks. The bitmap lines on one half of the profile are traced with a spline line, mirrored and then a scale is applied to get it to the proper size. The 3D model is a simplified version of the actual part. I just need the basic dimensions for sizing of the other parts. The same base profile for the but pad is used to create the profile for the adjustable mounting plate.


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## jbolt

09kevin said:


> Looks good Jay! I noticed that you were playing with the 4th axis in another post, have thought about using it on some of these parts?
> 
> Kevin



The barrel guard and the mount for the barrel will have operations on the 4th axis. Mostly indexing moves for 2D tool paths. I still need to finish the stepper motor mount for my rotary table and get the post processor modified before I can try any 4th axis work. I have figured out how to do the CAM so that part of the puzzle is good to go.


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## Metal

Neat stuff, I'm still learning how to fixture stuff properly so it is extra interesting to me.

Turns out I can't indicate to save my life yet >.>


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## jbolt

I made a little more progress. I have started on the maim part of the stock.




The first three side are done in a vise. The front, top and left sides. The first was to drill the holes in the front and then run the top.

Tool paths for the top.



Top completed.



Next was the left side.



Left side ops completed.


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## jbolt

The receiver stock is done. I had a few anomalies with some of the tool paths where the cutter skipped over some of the details during the 3D passes. It's kind of strange where most finished dimensions are within a few thou which I think is good considering there were tool paths on 5 of six sides but there are a few that were 10 to 20 thou off, all on the 3D tool paths. Part of the path would be perfect and another part would be slightly off. I have some backlash in the system I need to take care of and it really shows in some of the blend lines.

I also discovered the 3D CAD model of the receiver I got from a friend wasn't modeled correctly. The important dimensions were there but the taper at the rear of the receiver is way off and the slot for the bolt handle is not deep enough. I'm going to try and recut the taper. Hopefully it comes out okay. I'm still trying to figure out how to use extra long end mills without leaving chatter marks.


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## talvare

Beautiful work Jay.

Ted


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## Bill Gruby

I normally am not intrigued by CNC machining. It does not do much for me, but this project is amazing and well documented. The videos are awesome. Thank you for taking the time to post this.

 "Billy G"


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## TomS

I'm not into guns but that is a beautiful piece of machining.  

Tom S.


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## jbolt

I was able to recut the back taper to more closely match the receiver and recut the pocket for the bolt handle so now the receiver stock is done.

Next is the part that mounts the barrel guard to the stock.


Solidworks Model



Rear side tool paths



2" x 3" x 2.5" block bored, turned and here getting the taper cut.



Bolted to the fixture ready to machine. Normally I would hold a part like this in a soft jaw but it needs to be milled on both ends so the same fixture can do both sides. That's a 1/2-13 bolt holding it in place.




Drilling and milling completed. I normally model the part and the fixtures and then do the CAM from that assembly. I can then run stock simulation to look for clearance or tool path issues. Because I did the fixtures on the lathe as they were simple I did not bother to model it. Well that bit me. I failed to adjust the default clearance height for one of the 3D contouring operations and when it finished it went to the safe Z that was too low and then to the starting position for the next tool which was across the part. That cost me a 1/4" carbide ball end mill when it tried to rapid through the steel bolt head at 50 ipm. Ugh!



Ready for the front side.



With all the roughing work I have done this week the cutting fines are wreaking havoc with the coolant pump check valve and I keep loosing prime on the pump. I need to sort that out before continuing.


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## sgisler

Very nice work! What are you using for CAM?


Stan
Sent from my iPhone using Tapatalk


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## jbolt

sgisler said:


> Very nice work! What are you using for CAM?
> 
> 
> Stan
> Sent from my iPhone using Tapatalk



I'm using HSMWorks which is a direct plug-in to Solidworks.


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## sgisler

Thanks! I wondered if that's what it was. I'm just getting my feet wet in Solidworks (was using Fusion but had to have sheet metal, so bought SW). 
Love the project, gives me some ideas!


Stan
Sent from my iPhone using Tapatalk


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## Sendit

How did you get the inlet for the receiver/redo the rear tang?


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## jbolt

Sendit said:


> How did you get the inlet for the receiver/redo the rear tang?



 Hi Sendit, I'm not sure what you are asking?


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## vertcnc

Looks great, nice work.


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## Sendit

jbolt said:


> Hi Sendit, I'm not sure what you are asking?



Jbolt,  sorry i was in a bit of a hurry when I typed my message.   How did you go about modeling the pocket  in the chassis for the receiver to sit in?    How did you correct the rear tang area since it was off the first time?  I'm trying to get a accurate model of a Remington 700 but I do not have the correct tooling just yet to be confident in my measurements


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## jbolt

The inlay is straight forward with the receiver being round. The size of pockets for the trigger, safety & bolt release were done by measuring the receiver/trigger and also one of the Bell Carlson stocks I have. Since I am using a box magazine I just used the magazine dimensions with some clearance for fit and measured its location on how it fits against the receiver. 

For the tang area the error was in my favor so material removal was necessary. The rear tang is not flat but has a slight radius to match a typical hunting style stock. I didn't bother with that since it is not important for this build. 

I have not fully modeled the receiver. Because I am not trying to make a receiver all I need is the relevant dimensions to do the inlay.


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## jbolt

I couldn't find a check valve locally that would work and it was a week lead time to order one so I rolled my own. Works great!. I posted a quick *build thread* on that if anyone is interested. 

With the coolant system operational I was able to finish the last op on the barrel guard mount. The 2-1/2" flute 3/8" end mill chatters like crazy no matter what I try. Maybe solid carbide would be better but since this project is getting painted I can live with it. It just adds some handwork. The slots will be done on the 4th axis. The last photo is the fixture parts.


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## vertcnc

For those deep cuts I have used a reduced shank carbide end mill.  Various sizes are available. I have used the 3/8" with the flute length of 5/8" and the shank is something like .370.  It takes a few steps down for deep pockets or in your case, outside profile. Then a finish pass of .005 pretty much removes all tooling marks.  Also make sure you only have the tool sticking out of the holder the min. required. I purchased these from Maritool in Woodale, IL  (they have an online store.)


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## jbolt

Thanks vertcnc. I figured there was something like that. I'm familiar with Maritool. Of course now I have done all the deep stuff on this project.


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## Silverbullet

Watching for more very nice build. What's your finish weight target. About seven pounds I'm guessing.


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## jbolt

Silverbullet said:


> Watching for more very nice build. What's your finish weight target. About seven pounds I'm guessing.



The stock or the whole rifle?


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## jbolt

A little more work completed. I got the 4th axis completed and running but the first motor I used was too long. I had to put a sorter stepper motor and coupler so it would clear the new enclosure so I could use the flood coolant. It also took a while to get the Mach3 post modified correctly for the 4th axis. 

This is the vent slots on the barrel guard mount. To index in HSMWorks I had to create an individual tool path for each slot. That's just a matter of duplicating the first tool path and editing it for the correct orientation and contour of the next slot.




I decided error on the side of caution and run a test part before committing the actual part to the last operation on the 4th axis which I am still getting used to. I turned a piece of stock the same diameter as the finished part and set the offsets for the actual part so if it was successful then the actual part can be ran with no other setup needed other than orientating the part in the 3-jaw.

Success! (and no the chuck key was not in during the machining) 




Here is the actual part mounted in the fixture in the 3-jaw ready to machine.




Machining completed!




That was the last operation for this part so it is now completed.


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## TomS

Beautiful piece of machining!

Tom S.


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## jbolt

TomS said:


> Beautiful piece of machining!
> 
> Tom S.


Thanks Tom. There is definitely room for improvement. I'm still discovering the appropriate tools for certain jobs.

I desperately need to fix the backlash in the system that has creeped in over the last two years. Not so bad for one off parts but it really shows with the multi faced assemblies. The double ball nuts seem to be the way to go.


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## jbolt

Well it was bound to happen sometime. I scrapped my first part. I started on the barrel guard and I think I was a little too optimistic about my setup.

Here is the CAD.




Here is the guard modeled in the fixture.




Here is the turned guard blank ready for machining.




The guard is mounted between a plate that is attached to the rotary axis and a plug that rides on the tail stock taper. A threaded rod is between the plate and plug to hold the guard under compression. The guard at the plate end is tapered and is very thin. There was not enough surface area to properly grab the face of the plate.




In addition my lead in speed was too fast, the lead length and lead radius were too small. 

The end result. 




I remade the plug that is pressed into the plate with a larger OD that is a press fit into the guard. On the tail stock end I drilled out the center of the plug and made a Chicago bolt to go through the plug. The bolt head is counter-bored for the tail stock. This gives me greater clamping pressure. 




I also decided to not turn the OD and taper yet to leave a greater clamping surface. 

Here is the revised fixture.




Ready to try again as soon as I tweak some of the g-code.


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## jbolt

Things went pretty well today. I learned a few things but overall I'm happy with the result. 

First op was to cut the flats on eight sides. I'm glad I modeled the fixture in solidworks. I caught a cut interference with the button head cap screws that hold the fixture to the rotary axis. I was able to change the lead out to avoid it.




Next was drilling the holes.




Next is milling the slots.







Next is the chamfer on the slots. I was getting some chatter out at the tail-stock end. At first I thought it might be because as the slots were being cut the torsional rigidity was being compromised allowing that end to twist a little. Turned out the tail-stock was not tight. Oversight on my part.






Final op on the 4th axis is the front contour. I couldn't figure out how to do this tool path in HSMWorks so I used Aspire for the CAM. I added some additional screws to keep the end plug from rotating in the part during cutting.




Off to the lathe to turn the final OD and rear taper.





Completed part ready for final deburing.


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## TomS

jbolt said:


> Things went pretty well today. I learned a few things but overall I'm happy with the result.
> 
> First op was to cut the flats on eight sides. I'm glad I modeled the fixture in solidworks. I caught a cut interference with the button head cap screws that hold the fixture to the rotary axis. I was able to change the lead out to avoid it.
> 
> View attachment 142418
> 
> 
> Next was drilling the holes.
> 
> View attachment 142419
> 
> 
> Next is milling the slots.
> 
> View attachment 142420
> View attachment 142421
> View attachment 142422
> View attachment 142423
> 
> 
> Next is the chamfer on the slots. I was getting some chatter out at the tail-stock end. At first I thought it might be because as the slots were being cut the torsional rigidity was being compromised allowing that end to twist a little. Turned out the tail-stock was not tight. Oversight on my part.
> 
> View attachment 142424
> View attachment 142425
> View attachment 142426
> 
> 
> Final op on the 4th axis is the front contour. I couldn't figure out how to do this tool path in HSMWorks so I used Aspire for the CAM. I added some additional screws to keep the end plug from rotating in the part during cutting.
> 
> View attachment 142427
> 
> 
> Off to the lathe to turn the final OD and rear taper.
> 
> View attachment 142428
> View attachment 142429
> 
> 
> Completed part ready for final deburing.
> 
> View attachment 142430
> View attachment 142431
> View attachment 142432



Very Nice!

Tom S.


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## Boswell

Awesome work Jay.  You make this look easy.


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## jbolt

Boswell said:


> Awesome work Jay.  You make this look easy.


 Thanks Boswell.  

It doesn't feel easy sometimes. It has been a lot of fun though and I'm learning a lot.


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## jbolt

Here is the picatinny rail.

My original 3D model of the receiver was not correct so I had to spend some time drawing one with enough correct details to finish the picatinny rail model. I searched the interweb for dimensions of the radius of the rear bridge where the rear scope mount sits. It also sits lower than the front. Everyone I found was different and varied a lot so I figured out a way to measure it using a TDI in my drill press and a machine vise on a X Y table.

By zeroing the TDI on the center-line of the receiver and moving a measured amount right and left I could plot the radius. Height gauge was used to measure the offset.





Here is the old (left) and new (right) 3D model.





Machining of the picatinny rail. It was machined from 1" x 2" stock. The CAM was done with the model inserted into a model of the stock to set the coordinate origins for the top & bottom operations. The full rail is 22.2" long which exceeds my table travel so it was made in two pieces. The main piece shown here is 16.2" long

Tool paths.





The bottom was done first. For the top operations the part can be held by the machined sides under the bevel and still have room for the cutting tools.

The rail has a built in 25 MOA slope when installed so all the bottom finishing operations were 3D tool paths.

After 3D adaptive roughing with a 0.5" 4 flute roughing end mill.




After the 3D horizontal profiling wth a 0.5" 2 flute ball end mill. Step over on the radius-ed areas that contact the receiver were done with a 0.012" step over. The balance was done with a 0.04" step over just because I like the look. When installed it is mostly hidden. The sides and bevel were done with a 0.375: drill mill.




Test fit on the receiver. Perfect! Unfortunately there is a shadow at the base so it does not show well in the picture.




Now the top.




Finished rail.


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## jbolt

Before I can drill the mounting screw holes in the picatinny rail I need to assemble the hand guard and double check the measurement from the receiver mount holes to the drilled holes in the guard just in case of error creep.

The guard is pressed onto the guard mount and they need to be indexed to each other. To do this I made a jig to hold the guard mount so that the flat on the guard could be used for indexing. 

The jig.






Here is the stock partially assembled to do final measurements for the scope rail.


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## Firestopper

You do very nice work Jay, your extra effort in detailing and posting is inspirational. Keep it coming!


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## TomS

All I can say is, WOW!

Tom S.


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## Livnpaintball

Top notch!


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## Livnpaintball

That's the stuff!


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## MontanaAardvark

Good stuff, Jay!  

Just found this thread, and need to add it to the ones I follow.


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## countryguy

Man oh man that is Sweet!  My Son is going to flip when I show him this post!    Two quick q's... What do you use for coolant flood?  I'm  ready to start that now also.    In the pic below, you have two vises being used to hold a long part.  I've been looking for something exactly like that.  Not too small, Not to big. You happen to know who made those ?     Again... AMAZING work.   incredible patience! 

...again, AMAZING post.


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## jbolt

countryguy said:


> Man oh man that is Sweet!  My Son is going to flip when I show him this post!    Two quick q's... What do you use for coolant flood?  I'm  ready to start that now also.    In the pic below, you have two vises being used to hold a long part.  I've been looking for something exactly like that.  Not too small, Not to big. You happen to know who made those ?     Again... AMAZING work.   incredible patience!
> 
> ...again, AMAZING post.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> View attachment 229091



I'm currently using Koolrite 2290 coolant. So far this is the best I have found for being machine and user friendly. No rust issues and almost no odor.

The vises are 4" CNC style from Shars. They are great for the price but with a couple of drawbacks. The vises are not matched so one is a few though taller than the other and they only open 3.8". Other than that no complaints.


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## jbolt

Now that life is settling down a bit this project is moving back toward the front of the line. Unfortunately I found and issue with the receiver block where I had modified a feature in the CAD model that had a relationship to the magazine well position. I didn't catch that and the result is the mag well is out of position by 0.1" which is too much to fix. Now that I have to remake that part I decided to change from a single stack magazine to a double stack ACIS compatible style. I'm also going to try some reduced shank end mills for the deep milling of the mag well and trigger well to see if I can improve the surface finish and avoid the chatter of the long flute end mills. I have some reduced shank end mills on order from Mari Tool so hopefully they will be here soon and I can get this project going again.


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## spumco

Jbolt,

Superb.  I bought a chassis for a Savage in my pre-CNC days, and your's looks every bit as nice.

FYI - American Gunsmith Tools is an off-shoot of Lakeshore Carbide, and they have some very nice long-reach reduced shank 3/8" end mills specifically designed for deep pocketing the magwell and FCP on AR10/15's.  I have used mine and it's quite nice - so if the Maritool isn't to your taste I can recommend the AGT carbide stuff.  I suspect anything you get from Maritool will be awesome, but I figured I'd just throw it out there as an alternate.


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## jbolt

spumco said:


> Jbolt,
> 
> Superb.  I bought a chassis for a Savage in my pre-CNC days, and your's looks every bit as nice.
> 
> FYI - American Gunsmith Tools is an off-shoot of Lakeshore Carbide, and they have some very nice long-reach reduced shank 3/8" end mills specifically designed for deep pocketing the magwell and FCP on AR10/15's.  I have used mine and it's quite nice - so if the Maritool isn't to your taste I can recommend the AGT carbide stuff.  I suspect anything you get from Maritool will be awesome, but I figured I'd just throw it out there as an alternate.



Thanks for the heads up on AGT. I will keep them in mind. I had better like the Maritool cutters for the cost. LOL


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## jbolt

Finally got to start on the remake of the receiver block. Based on the previous part I went through the CAM and refined some of the tools and tool paths. I was able to cut the top today which is the inlet for the receiver and magazine well. I'm super thrilled with the results of the reduced shank carbide end mills. 

Here is the magazine well from the fist part. I used an extended length 3/8" HSS end mill and tried to take a full depth finish cut resulting in chatter marks. The corners were pre-drilled with a 1/8" hole so the cusps had to be filed by hand.




Here is the new part finished with the reduced shank end mills. On this part I pre-drilled the corners 3/16" since the ACIS magazines have a larger corner radius. On both parts the mag well was pre-drilled with 1/2" holes and then roughed out with a 1/2" roughing end mill leaving 0.01" for finishing. I ran a 3/8" reduced shank carbide end mill set to do a finish pass and then a spring pass. DOC was .185" at 48 IPM, 6000 RPM. The final finishing to remove the cusps was done with a 3/16" reduced shank end mill with a DOC of 0.06" at 40 IPM, 6000 RPM. No filing needed and the magazine is a perfect fit.




Here are the tools.




And a shot of the completed inletting.


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## Billh50

Beautiful work !
I wish I had the capability to do that type of work. I can draw em but do not have the machinery or knowledge of cnc to do it.


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## MontanaAardvark

Looks very nice.  

Do you plan on broaching the corners of the mag well to make them more square?


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## jbolt

MontanaAardvark said:


> Looks very nice.
> 
> Do you plan on broaching the corners of the mag well to make them more square?



No need to broach or file. The ACIS style mags fit with the 3/32" corner radius.


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## jbolt

Billh50 said:


> Beautiful work !
> I wish I had the capability to do that type of work. I can draw em but do not have the machinery or knowledge of cnc to do it.



Thanks Bill. The CNC conversion has been a fun and yet frustrating at times but overall rewarding journey. Makes me want a proper VMC.


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## Bamban

Jay,

That is one fine project. You need to finish the build in one of those hot rod 6mm, and shoot it in competition.

nez


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## jbolt

Bamban said:


> Jay,
> 
> That is one fine project. You need to finish the build in one of those hot rod 6mm, and shoot it in competition.
> 
> nez



Thanks Bambam. It will be chambered in 6.5 RSAUM.


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## spumco

That looks awesome, well done.

F&S, WOC, DOC for rougher?  Any chatter with that stickout?


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## Firestopper

Beautiful work Jay! Following along with your cool build.


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## Bamban

jbolt said:


> Thanks Bambam. It will be chambered in 6.5 RSAUM.



Now, that's a sweet cartridge, a 1000 yard Coyote getter.


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## jbolt

spumco said:


> That looks awesome, well done.
> 
> F&S, WOC, DOC for rougher?  Any chatter with that stickout?



Rougher is a 4 flute Cobalt HHS with a 2.625" flute length. The mag well was pre-drilled with 1/2" and 5/8" holes to reduce the amount of material to remove and allow the chips to flush out of the pocket. The width of cut varies but I used .2 as the average. DOC was 0.072", 4850 RPM at 50 IPM. The pocket is 2.575 deep. Tool deflection calcs at about .001"


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## spumco

Cool, thanks.  I have a corncob like that (shorter) and was wondering about the F&S.  Haven't used it yet, but some day I'll need to butcher a bunch of aluminum with it.


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## jbolt

I use G-Wizard for feeds and speeds


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## MontanaAardvark

jbolt said:


> I use G-Wizard for feeds and speeds



+1 

A really good program.  That and his graphical G-code editor that shows the toolpaths are really worthwhile.


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## Boswell

jbolt said:


> I use G-Wizard for feeds and speeds



Also +1 for G-Wizard and his other applications.  Nice Site, Nice application. Although my mist coolant system does not clear chips as quick as G-Wizard thinks and so I often run at a lower feed rate. I probably just have not figured out where to enter my coolant method.


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## jbolt

G-Wizard has been worth every penny for time and tools saved. 

For the question on the corner radius of the magazine well. Here is a photo of a magazine in the well to show that no broaching was needed. Both the Alpha mag and Accurate-Mag fit perfect.


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## MontanaAardvark

jbolt said:


> G-Wizard has been worth every penny for time and tools saved.
> 
> For the question on the corner radius of the magazine well. Here is a photo of a magazine in the well to show that no broaching was needed. Both the Alpha mag and Accurate-Mag fit perfect.
> 
> View attachment 242195



Thanks.   

I'm more familiar with the AR world (15s and 10s) and "broached mag well" is one of those buzz words they use all the time.   The thing is that marketing buzz words usually have nothing to do with reasonable ways to do things. I'd guess it's just faster for a company with a big press to broach the mag well than do a tool change to swap end mills and run a pass into those corners.  

The prints for the "standard" AR-15 or AR-10 call out a .062 radius instead of the 3/32 your refer to for the ACIS magazines.   I've never tried both ways, but I'd guess that while .062 radius is harder to cut than the 3/32,  a 1/8 EM isn't that different from a 3/16 EM if its fed slowly enough.


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## jbolt

MontanaAardvark said:


> Thanks.
> 
> I'm more familiar with the AR world (15s and 10s) and "broached mag well" is one of those buzz words they use all the time.   The thing is that marketing buzz words usually have nothing to do with reasonable ways to do things. I'd guess it's just faster for a company with a big press to broach the mag well than do a tool change to swap end mills and run a pass into those corners.
> 
> The prints for the "standard" AR-15 or AR-10 call out a .062 radius instead of the 3/32 your refer to for the ACIS magazines.   I've never tried both ways, but I'd guess that while .062 radius is harder to cut than the 3/32,  a 1/8 EM isn't that different from a 3/16 EM if its fed slowly enough.



If I was making a thousand of these a day, broaching would be the way to go.

The first iteration was setup for a single stack Wyatt magazine that needs a 1/16" radius. I pre-drilled the corners with a 1/8 drill and did the wall finish with a 3/8 end mill which required filing the remaining cusps. In the at scenario using the 3/16" end mill would reduce the size of the cusps. I know Maritool does not have a 1/8" reduced shank end mill. I'm not sure if one exists and if it does it may not be long enough.


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## spumco

I'm using both G-wiz and HSM Adviser.  Not sure which one I like better yet, but both have been useful.  I'll make a decision in about 6 months when the subscriptions need to be renewed.

Less happy with G-editor as the conversational features are essentially useless unless you're proficient at heavily modifying the post processors or have a bog-standard controller (I'm not, and I don't).  That, and some of the conversational functions aren't available despite being displayed on the screen.

Thus far, I've found that the Fusion 360 simulator and the simple editor in my control software suffice for fiddling with the programs I've run - so I probably won't be renewing the G-editor license.

As for broaching a mag well or similar pocket...  haven't done it yet, but I've been toying with the idea of making a single-point broach to fit the mill spindle and programming it to walk over in to a corner a 'thou at a time.  There are a couple of manufacturers making spindle-mounted broaches that look sort of like toothbrushes with a single cutting edge for doing internal splines or key-slots.  They claim that the loads on the spindle bearings when doing small step-overs are significantly lower than for drilling or other normal operations.

I was thinking of carving up a square chunk of tool steel that has a bit of lead, a raked tooth, and a round shank to fit the spindle.  Flat sides to keep it aligned in the pocket (with a bit of clearance), and then up-down-up-down as it walks in to the corner to clean up cusps.  Spindle off, of course, and it would only work on a through-pocket for chip evacuation.

A servo spindle would be the ticket here for indexing and then I wouldn't need a 'guide' section on the tool - but (sadly) I don't have one of those.


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## MontanaAardvark

spumco said:


> I'm using both G-wiz and HSM Adviser.  Not sure which one I like better yet, but both have been useful.  I'll make a decision in about 6 months when the subscriptions need to be renewed.
> 
> Less happy with G-editor as the conversational features are essentially useless unless you're proficient at heavily modifying the post processors or have a bog-standard controller (I'm not, and I don't).  That, and some of the conversational functions aren't available despite being displayed on the screen.
> 
> Thus far, I've found that the Fusion 360 simulator and the simple editor in my control software suffice for fiddling with the programs I've run - so I probably won't be renewing the G-editor license.
> 
> As for broaching a mag well or similar pocket...  haven't done it yet, but I've been toying with the idea of making a single-point broach to fit the mill spindle and programming it to walk over in to a corner a 'thou at a time.  There are a couple of manufacturers making spindle-mounted broaches that look sort of like toothbrushes with a single cutting edge for doing internal splines or key-slots.  They claim that the loads on the spindle bearings when doing small step-overs are significantly lower than for drilling or other normal operations.
> 
> I was thinking of carving up a square chunk of tool steel that has a bit of lead, a raked tooth, and a round shank to fit the spindle.  Flat sides to keep it aligned in the pocket (with a bit of clearance), and then up-down-up-down as it walks in to the corner to clean up cusps.  Spindle off, of course, and it would only work on a through-pocket for chip evacuation.
> 
> A servo spindle would be the ticket here for indexing and then I wouldn't need a 'guide' section on the tool - but (sadly) I don't have one of those.



There's a fantastic video on YouTube where a guy melts down 5 pounds of aluminum soda/beer cans, then casts and machines an AR-15 lower from them.  At one point, he takes a piece of tool steel stock and makes a broach just like you describe.  I think he just nibbles into the corner with the broach either in a drill press or in his milling machine.   

The video is 19 minutes long, but I can't think of any video that long I've watched that held my attention as well for the full duration.


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## jbolt

MontanaAardvark said:


> There's a fantastic video on YouTube where a guy melts down 5 pounds of aluminum soda/beer cans, then casts and machines an AR-15 lower from them.  At one point, he takes a piece of tool steel stock and makes a broach just like you describe.  I think he just nibbles into the corner with the broach either in a drill press or in his milling machine.
> 
> The video is 19 minutes long, but I can't think of any video that long I've watched that held my attention as well for the full duration.



That's awesome. What's more American than making an AR from recycled beer cans.


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## spumco

jbolt said:


> That's awesome. What's more American than making an AR from recycled beer cans.



Maybe buying 80% Sten tubes at Home Depot, but I think you're right on target.


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## Sendit

Silly question but how did you measure the radius of the mag?


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## jbolt

Sendit said:


> Silly question but how did you measure the radius of the mag?


Radius gauge.


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## jb7734

I know this is an old thread but do you have any updates? I want to do something similar with an integrated scope rail to suit a military mauser action.


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## jbolt

jb7734 said:


> I know this is an old thread but do you have any updates? I want to do something similar with an integrated scope rail to suit a military mauser action.


Unfortunately I shelved this project after scraping two receiver blocks. The project was taking longer than I wanted so I went a different route and built a tube gun around this receiver and barrel. That project is finished and operational with the exception of powder coating.

I may go back to the original project in the future. I need to do some redesign work to lighten and slim down some components. 

Then there is the fact that between then and now I have moved and my shop is not fully setup yet.


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