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Chassis Build

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MontanaAardvark

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#61
Looks very nice.

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

jbolt

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#63
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.
 

Bamban

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#64
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
 

jbolt

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#65
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.
 

spumco

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#66
That looks awesome, well done.

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

firestopper

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#67
Beautiful work Jay! Following along with your cool build.
 

jbolt

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#69
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"
 

spumco

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#70
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.
 

Boswell

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#73
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.
 

jbolt

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#74
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.

20170920_192405.png
 

MontanaAardvark

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#75
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.
 

jbolt

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#76
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.
 

spumco

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#77
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.
 

MontanaAardvark

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#78
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.
 

jbolt

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#79
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. :encourage:
 
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