Jump to content
Brian Enos's Forums... Maku mozo!

CNC Mill Retrofit- Gunsmithing Setup Questions


MikeRush

Recommended Posts

Last year I sold my open gun and picked up 3 2011 frames and a Series 1 Bridgeport CNC complete with tape drive with the intention of converting it to modern CNC.

I finally am in a position financially to make the conversion happen, so I have the new stepper drives, and I will be picking up the VFD and breakout board this week. I am currently planning on running Mach 3. I have zero milling experience, but I am generally technically minded and know I can accomplish anything I set my mind to.

My questions aren't so much about the conversion as features/accessories I should consider including- I would very much appreciate input on this!

1. I've been digging through threads on some of the CNC forums and it seems like people get really excited about high rpms. I may end up doing some work with aluminum (mag pouches, maybe a race holster, 80% or 0% lowers, etc) but mainly plan on slides and frames. I am planning on keeping the stock motor and belt drive for now, although I will be using the VFD for speed control. Will 4200 rpm generally be sufficient to give me a decent surface finish in typical smithing operations?

2. It has most of a mist coolant system intact, should I get that running or ditch it and go straight for flood cooling?

3. I'm looking at a Kurt vise, the D675 or D688- do I need the swivel base? It seems like it would simplify certain operations but that I could accomplish similar things with the CNC. I will probably end up with one eventually, but I don't know how immediate the need for one is.

4. My last question for now is about the Para/Clark cut- I've heard of using a 3/8 endmill, the EGW .360 endmill, or a smaller endmill and programming a toolpath to make the cut. I am leaning towards just picking up the EGW cutter as for now I am only doing my own guns, and think the HSS will probably last for my purposes but I could be persuaded to take another route.

I am reading everything I can and hope that between putting the conversion together and setting everything up I will get a good feel for the machine and processes involved.

I've started to gather tooling- I have some collets, endmills, etc but I will be doing additional research before I finish that out. I will be placing an order for edge finders, indicators, parallels, etc soon- are there any other things besides the typical "start with these things and then buy what you need" that have made your life easier? Jigs, fixtures, tools, etc?

I appreciate any input on this as I am trying to get up to speed and making chips successfully with hopefully a minimum of waste and reconfiguration. I have been greatly encouraged by those who have paved the CNC way on this forum!

Link to comment
Share on other sites

Hello Mike,

I can only answer some of your questions:

1. I use 3/8" carbide for Para/Clark ramp cuts. It cuts straighter than HSS.

2. You need to make a jig to hold the frame vertically, not only for Wilson/Nowlin ramp cuts, but for bowtie VIS on non-ramped barrels.

3. The Yavapai slide jig on Brownells is nice to have for lowering ejection ports.

Check out 1911Pro forums for jig and fixtures for sale.

Link to comment
Share on other sites

Install a flood coolant system. Spray mist will quickly fill your shop with chemical mist and will eventually make a sticky mess of everything in the shop. You also do not want to breath all that stuff. Do keep the spray mist system and run it with air only when you need to blow away chips from the cutting area.

4200 rpm is plenty for the work you will be doing. High speed spindles have an advantage in production work when time savings take precedence or when three axis milling complex contours.

Get the Kurt 688. You will eventually need the wider jaw opening. Make several sets of soft steel and aluminum jaws. They can be machined to hold unusual shapes or round parts and can be cut into if needed while machining your parts.

As for the swivel base I'm on the fence. Can be useful but with CNC programming the needed angles are easy in most cases. Put the money into good quality carbide tooling for now.

Edited by Zoomy
Link to comment
Share on other sites

Everything Zoomy said is right on the money. I'm a tool & die maker of 35 years. I run my own shop at home with 2 full size CNC mills making prototypes of new inventions.

My mills are way easy to program because of Conversational Programming. With that, you can just fill in the blanks on the screen with numbers from a 2D drawing.to create the toolpath. I have Milltronics mills. You can buy just the control and put it on your machine.

I have 3 Kurt 688 vises. That is the one to get. I never use the swivel bases. Learn to make your own soft jaws for the vise as mentioned above. These are your cheapest and most effective fixtures combined with aluminum plate that can have parts bolted to it and machine all the way around in one setup. Also make soft jaws with steps (step jaws) to avoid using parallels when possible. The parallels fall over, get chips under them, need constant cleaning, etc. You still need a set for one off stuff though.

I never run over 3200 rpm. I use a lot of carbide AND High Speed Steel cutting tools. They both have their place. Get a good 3" 45 degree insert face mill and a 1" insert end mill. Inserts are cheaper than whole tools. For the Para/Clark cut I would use a !/4" carbide end mill and program it to cut a radius. You also want to step it down rather than do the whole depth at once.

Link to comment
Share on other sites

Thank you all for the helpful information and recommendations! I'm using this to prioritize my spending and line out the rest of my conversion.

It is good to hear it will be adequate- poking around CNC forums gives the impression that if it doesn't have a 10k rpm spindle, servos and a tool changer it might as well be hauled off as scrap.

Link to comment
Share on other sites

^^^ All that is true if you want to make money with it building parts. If you just want to screw around, then time isn't as much money.

I'm getting rid of my machine for all the reason above and getting something with all those things...

Link to comment
Share on other sites

Well, some guys who have looked at it a few weeks ago are supposed to come pick it up, along with all the tooling that's left, a few vises, and my sweet little air compressor for $9500.

Link to comment
Share on other sites

Haha, no, not 100% sure yet, but the ideal machine is a brand new Brother Speedio. I selected the same machine at my work and it is incredible. Backup plan is a used machine like a Haas Super Mini Mill. Let's not divert this thread though. The machine I built was perfect for toying around and building prototypes while learning. Now I have a desire to build parts in volume, so the needs have changed and I need a machine aligned with those things.

Link to comment
Share on other sites

Fortunately for me I think my usage level would be limited to hobbyist/prototyping.

I like the knee too as I may wind up boring Harley cases, milling 80% lowers, and low production belt gear all on the same machine.

Jriera,

May I ask what breakout board and software package you are using? I got new Leadshine line voltage drives that should give me pretty decent rapids but I haven't decided on a breakout board and if I want to use a smooth stepper or not .

Thanks,

Mike

Link to comment
Share on other sites

I suppose I should add the machine is a Boss 5 that I picked up running with quick change tooling and some collets. If it works well and holds good tolerances I may power the knee and add a rotary table later on.

It has the rigid ram and seems pretty burly.

I'm planning on keeping the stock stepper motors for now but may upgrade later if I feel the need.

Link to comment
Share on other sites

I am using PMDX-126 breakout board (and other PMDX goodies) and Warp9 smooth stepper. Mach 3 is the software I use.

I did reuse the steppers that came with my mill and added Gecko drivers (G203v's at 80 Volts)

I haven't seen the need to change the steppers, they are really fast and precise.

I recommend you to stay away from Chinese eBay stuff ... buy once, cry once.

Edited by jriera
Link to comment
Share on other sites

The PMDX was one of the boards I was looking at, or the CNC4PC setup. I'm thinking of a Hitachi VFD for the spindle as well. I'll probably use Mach 3 too.

I was looking at the Gecko drives but was persuaded to try the Leadshines. Hopefully I don't cry twice.

Do you have a ballpark figure on how long wiring the conversion took? Trying to prepare my girlfriend for me losing my tan and having less free time. Obviously skill is a factor but I am half decent at soldering etc.

It felt good to rip off the huge cabinets full of heavy old school electronics, that's for sure...

Link to comment
Share on other sites

It took me two weekends to rip everything apart, find the wires and install the new stuff.

I went the VFD route and I plug it to a PMDX-107 speed control ... works fairly nicely. remember it is a LARGE spindle motor buy a bigger VFD than required.

Link to comment
Share on other sites

Stay away from CNC4PC, I started with their stuff and could not get it to work, the build quality is not there. I ran PMDX 126, ethernet smooth stepper, and PMDX 107 for the spindle. It is a very well thought out integrated system with execellent documentation. Very happy I ditched the other stuff.

Link to comment
Share on other sites

Stay away from CNC4PC, I started with their stuff and could not get it to work, the build quality is not there. I ran PMDX 126, ethernet smooth stepper, and PMDX 107 for the spindle. It is a very well thought out integrated system with execellent documentation. Very happy I ditched the other stuff.

This is still an open loop system?

Link to comment
Share on other sites

Yes, mostly Open Loop, they can be upgraded to Close Loop but usually they are too expensive as an upgrade. You can always add feedback via Chinese glass scales and something like Calipe2PC, but having half a thousand resolution on the stepper is good enough for me for non-commercial applications, I can afford to miss one step or two without affecting anything (too badly)

Link to comment
Share on other sites

Mine was closed loop, servo motors with encoders, but no scales. Turns out that scales are rare, even on full-blown VMC's.

This was my driveway this morning, as the machine I built left.

20140621_135502.jpg

20140621_151559.jpg

Link to comment
Share on other sites

Mine was closed loop, servo motors with encoders, but no scales. Turns out that scales are rare, even on full-blown VMC's.

This was my driveway this morning, as the machine I built left.

20140621_135502.jpg

20140621_151559.jpg

Did you run mach 3 with the encoders? Just learning sorry for all the questions.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...