View Full Version : Jig for machine stock inlet
06-23-2008, 10:42 PM
I'm looking for ideas with pictures if possible for building a jig for initial machine inlet on benchrest - target gun stocks. Jig would mount on Bridgeport type milling machine.
Thanks for help. Chuck
06-23-2008, 10:45 PM
Is what a lot of guys are using that do any bulk work. A manual mill with a jig would be time consuming wouldnt it??
06-23-2008, 11:00 PM
I'm not doing a "volume" of work, and what I'm looking for is a stock holding fixture that would allow easy repetitive holding of the stock level and plumb, then index rotate on centerline. Also, adjustment off level would be nice. People have been doing this long before CNC, but even with a CNC machine, you still need to hold the work and set it up for the cut. Thanks again, I hope this clarifies my interests. Regards, Chuck
06-23-2008, 11:08 PM
Machinist Vice for Mills???
06-23-2008, 11:59 PM
I've done a number of McMillan MBRs and big 50 stocks and one laminated from a blank. It was for me. I have a 42" B'port table so the travel is a lot less than that. I've held the stocks in a Kurt vise, gently, but both ends were clamped down after building up a stack of blocks to hold things in place. It takes a lot of time, a lot of setups, tilting the head and tramming it back in, and a lot of "trying" the barreled action in the stock. You have to move the stock from end to end on the table to make all of the cuts. I would never consider doing a laminated stock from a blank for someone else. Way too much time and too many setups.
The McMillans were inletted for custom actions and came out very nice. The bolt release cuts in the stock require several setups for small cuts. But that is all necessary if you want a good looking stock to metal fit when finished.
I have Futaba .0002 digitals which are very nice. Trying to do this w/o digitals would be a nightmare, IMO.
Sorry, I can't offer any help with your request for info but wanted to let you know that it can be done "the old fashioned way".
06-24-2008, 10:14 AM
Here's a jig I made to CNC inlet by numbers and profile the shape from a digitized pattern. There is a 5/16" hole 1" below centerline in the forend and two 3/8" holes in the buttstock. I had to build drilling jig to mill off the back of the stock square and drill with cordless & drill bushings the locating holes in one setup. The buttstock was attached to a 4th axis and machining was done at 12, 6, 3 & 9 o'clock. The steady rests in the middle just barely touch the stock and when the stock is on it's side there is a locating steady that goes through the magazine.
06-24-2008, 12:47 PM
For the life of me, I cannot remember where I watched it now, but there was a video kicking around from a company showing the full process of manufacturing a fibre glass stock, and for the inletting part they had a template with a follower connected to a router, I guess it would be called a duplicater, above a jig where a stock would be clamped, and I am not joking but it took about 30 seconds to inlet. Banser Rifles seems to spring to mind, but I have done a search and cannot located them. Hope this helps.
06-25-2008, 06:56 PM
This jig looks like it has neumatic clamping..
06-26-2008, 08:00 PM
Thanks for your ideas. The wood stock set up is what I had in mind, but I was thinking of clamp to but stock for fiberglass stocks, same up forward. Center steady looks to be a good idea. Others must do this routinely, but I sure would like to see more ideas before I finalize my plans. BTW, that video was awesome, wow would I like one of those machines!! Way out of my pay grade! Fun to watch though, amazing what modern CNC production machines will do. Thanks again, Chuck
06-26-2008, 10:03 PM
I don't run the big Mazak any more and now do stocks using my Bridgeport (copy) with a 2 axis Prototrak CNC or my stock duplicating machine. If I clamp a stock in the mill I have a set of padded tall jaws about 4" that I replace the standard jaws on my Kurt 6" vise. I clamp the forend in these and the buttstock is clamped in a versa vise that is clamped to the table. I can put a wiggler in the spindle and dial the stock in for the top inlet. Flipping the stock over poses another lengthy setup to get everything lined up. Another way to make the second side easier would be to build a dummy receiver that clamps into the mill vise. You could dial the vise in and find your x & y zero of the fixture. The angle of the bottom inlet could be built into the dummy receiver as well.
06-28-2008, 12:23 AM
I used one of these to help Lineup the stock blank. It was very...fly as you go..but it really helped getting it lined up to the Master stock on the duplicator..
It really needs a jig but it was quite impressive to incoporate it.
Have you seen these new center finders..saves on wiggle time. I am definitely getting one sooner or later.
Just curious what thickness are your stock blanks? What do they start at?
06-28-2008, 10:59 AM
The blanks I've got run from 2 5/8" and less. I can carve a Rigby stock out of a 2 1/4" blank. Not much fun setting up though.
I've tried for years to think of a good way to build & sell a jig that would clamp on a gunstock and have replaceable router tracer plates for different actions & barrels & floormetals. Something you could do both sides in one setup. Now that I've built my own duplicator, I've kind of lost interest in making it. The laser looks cool. I'd like to see how you used it in a setup.
06-28-2008, 03:00 PM
Apologies for hijacking the thread but this may be pertinent.
I sat the Laser on the cross beam at the closest end and aimed the laser down towards the far end.
There were two point screws with which the stock blank was mounted between.
I had hand-drawn a center line on the end of the stock.
With the Laser I just made sure the center lines were even and square to the screws. I also made sure the Master stock was aligned.
It may not have been necessary but it sure gave me some relief to see the stocks were aligned and square.
The Laser had a magnet inside it so it kept reasonably still.
This is where I think making a jig to attach to the laser to the duplicator would make it interesting.
You could maybe have an X and Y screw adjustment.
I had read an article of someone using these cheap lasers to level a mill. I thought it would be interesting to see what it could do on the Duplicator.
Nice Duplicator, by the way. I like the dust collector setup.
07-18-2008, 10:52 AM
I thought I'd revisit this thread with some additional links to some dust collection info. Getting rid of the dust in very important for your health and maintaining the accuracy in your other machines around the shop. My little shop is a 22x24 garage and with my electric beaver in the corner, in a few minutes of operation the dust cloud could cover every precision metalworking machine in my shop. I've got my machine backed into the corner and have built an 8' wall along side it. There's about 18" between the wall and the operating side of the duplicator. When I run my machine I use a one of those yellow Stanley squirrel cage fans on a stack of 4 milk crates blowing towards the 6" dust collection hole. The air flow is always clean as it passes by my head. The dust collector I'm using is a cv1800 5hp. It has a pair of very big hepa filters for the discharge and it does a fantastic job at pulling the fine dust out of the air. I've never seen any dust on any other surfaces around the shop after running a semi-inlet. There are few dust collectors that actually work as advertised. After doing a ton of research on the subject, I stumbled on Bill Pentz's website.
There is a ton of info on his site. He's got plans and research health info and shares it all. The plans he sells for a small fee. Bill has been forced out of his woodworking by breathing too much of the dust for way too long. He's done his best to come up with a design that works better than all the "real" ones. I ended up buying a big CV1800 Clear View cyclone that was built with his blessing and pretty much to his design.
The cyclone is priced pretty fair priced and phone help is very good. It's a kit that takes less than a day to have up and running. Pretty cool to watch the chips in the cyclone. It does make a lot of heat. My little window AC can't keep up very well. I hope to be in this business for the next 40 years and hope the machines and health I have will be with me for the duration. While working for a rifle company that builds duplicators, I used to go home every day and blow purple snot out my nose for hours. They had very little interest in taking care of the dust problem. Running stocks on the CNC and duplicator with a less than ideal dust collection system was some of my daily duties. Now that I've got kids I've got a different mindset when it comes to eating dust.
After installing and using my big cyclone for wood dust, I bought a miniCV06 to use with my surface grinder and 2" belt sander. I also have a line plumbed over to my blast cabinet. My surface grinder is 5 feet from my CNC mill and I haven't had any dust settle on my mill even after extended grinding sessions. They have some great videos on the web site of these cyclones.
I'm not trying to sell cyclones here. Just happy with the ones I've bought. It's probably not as big a deal to those that do this part time as a hobby. But when I close the door (popping my ears) of my little shop in the morning and work all day, I don't end up coughing out the door at beer-thirty in the late afternoon.:cool: NO more purple snot!
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