TargetTalk

Without wanting to start a big 'diy plastic guns' debate, has anyone tried 3d printing a set of grips???

It would be quite easy to 3d scan an existing grip, make adjustments to it with a 3d cad package and then print it out.

I guess it might be a little more slippery in ABS than laminate or walnut...

RichardinDorset wrote:
It would be quite easy to 3d scan an existing grip, make adjustments to it with a 3d cad package and then print it out.
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Boy, I laffed and laffed when I read that statement.

I work with 3d CAD all the time, though I use it for CNC machining rather than 3d printing. It is not trivial at all to get good data from a scan and import it into a CAD program. With most CAD programs subtle changes of compound curved surfaces is anything but simple or intuitive. Software and hardware to do that work quickly and well is in the 5 figure range. There are a lot of people making good progress with open source software and home made scanners but they are spending months futzing to get descent scans.

Not saying it's impossible, or that there aren't tools to do this. Just saying that the cost of scanners, software and 3d printers that are good for anything but making toy whistles is astronomical. And it's not trivial to learn to get good work out of them.

As one who designs in 3d and machines prototypes for a living, if you hired me to do it, it would probably cost as much as airfare and accomodations to visit Rink for a custom fit from them and a nice boat trip on the Main.

When Rink custom fits a grip they do all the mods on a real grip with clay or putty until they have the fit perfect and THEN they scan it and machine it. How would you ever know from looking at a 3d model on a computer screen if you had done the correct mods to fit your hand? Believe me, you would be in for several (maybe several dozen) iterations to get anything useable.

With anything but quick prototypes it's a lot better to CNC machine parts from a quality material than to print something that you want to keep and use for years from crappy plastic.

I have considered spooling up for this work because I would like to make perfect grips for myself. But I would be kidding myself if I thought I could make grips for others any cheaper or any better than Rink and Nill.

In the end the very cheapest, and best route is to buy a good grip that is close to a good fit and then modify. I assure you I could have a set of grips on my gun by this method and practice with them for a week before you got a good scan and modified the resulting model in CAD.

Maybe you have access to tools and skills I haven't heard of yet, but it often amazes me how people think these new tools are magic. They are still just very expensive tools that take great skill and training to use well. And time.

Spence

I had access to all the tools needed on my former job and scanned my Rink grip, also scanned part of the grip of a MU55. Combined both and printed the grip in ABS. This was a few years ago. Since then I sold the MU55. Maybe I still have the original files somewhere.

If you consider the tools and time needed, it's not worth doing it. I was just fun to try.

The printing part is the easiest... it's all the rest that is difficult.

Well I do have the tools to do it, admittedly not state-of-the-art, but certainly sufficient to do a grip.

I've made them before from walnut by hand and it's hard work, but interesting to do.

I agree that making adjustments on the cad model would be a challenge, as the scan is a point cloud and not a mesh, but I still think it would be interesting to try.

Even doing it in two stages, a basic blank which I could add putty or modeling clay to, the re-scan for a final version.

It seemed to me that it's an ideal object for 3d printing, unlike some other gun parts that need high precision etc.

Anyway I will post the results if I go ahead with it!

Richard, this looks like one of the most interesting projects anybody has suggested here. Didn't somebody post that shooting is a DOING activity?

This will be far more productive than the endless wingeing over whose secret coaching technique is best.

Cheers William!

I'll tell you all about my secret coaching technique later... If you're good...

I'll have to arrange a visit with my in-laws in Devon. Then we can meet halfway (Torquay, Exeter?) and you can reveal the secret over a pint of bitter.

Cheers to you!

Conversion of point cloud data to parasolid or parametric features is evolving. eg:


Once in that form editing is 'relatively' straightforward.

I was going to take the other route, create a complete parametric grip model as a starting point.

JamesH,

I don't want to constantly be damping the enthusiasm for this project. I have thought quite a bit about this route. I really like this kind of work.

In the diagram you posted, the destination CAD app is SolidWorks. While this app is arguably THE best mechanical design package and is rapidly becoming the standard, it is not a surface modeler and subtle manipulation of compound 3d surfaces is not it's strong suite. It isn't easy to make subtle changes in swoopy curves with SolidWorks. It is also EX-SPENS-IVE. I bring this up to show that just having fabulous 3d modeling software does not make 3d design changes trivial.

I think if all the shape modifications are made physically - and then scanned - to avoid trying to fit the grip in software (difficult without a 3d model of the hand in gripping position) the process can work quite well. Trying to change the shape of the grip in software to fit the hand will not end well. The remaining problem is that the final grip will still be plastic.

It is also a fact that a CNC machine sufficient to cut grips in wood can be had cheaper than a 3d printer and will likely be faster. Printing can make shapes with overhangs that would be difficult to machine without multiple setups.

spence

You print the grip as two halves split left/right and there will be no overhangs.

My 3d printer cost a lot less than a CNC mill!

Hello,

3d printing is a very generic name covering different technologies. Additive manufacturing seems to be a more appropriate name.

I have several grips made of nylon through the SLS (selective laser sintering) process. After starting with a parametric model for the grip, I proceeded with the scan of an existing grip, manufacture this with a less steep grip angle. This grip was modified and scanned again and is the base for my Tesro, LP10E and TOS 35 (ongoing project). The advantage of working with a digital model is the freedom of change, optimization (for max contact surface while still fitting in the box) and reproduction . Production can be milling in wood (Rink grips provides this option) or additive manufacturing. The nylon is great for grips (in my opinion). It can be filed and sanded, colored by textile paint or spray paint.

Kind regards,

Frits

[quote=
My 3d printer cost a lot less than a CNC mill![/quote]

3d routers can be had, ready-made, very cheaply - a few hundred dollars for one with an envelope big enough for a pistol grip. It doesn't take a $35,000 machining center to cut some wood grips. Thousands and thousands of people in the US have made such routers at home without access to any machine tools. One I know of is making rifle stocks with his home-built CNC router.

Depending on the grip it is still possible to have overhangs even when split down the center line of the pistol. I only mentioned overhangs because that is one area where 3d printers have a clear advantage. Speed and quality of materials favor the CNC router. Let me know when you get a file of a grip you like. Maybe with a little playing around I could hammer it into a tool path and cut something out of wood for your final version. Or delrin if you really prefer plastic. :-)

Spence

Spence,

Solidworks isn't cheap, granted, there is freeware around but I use Solidworks so I don't need it.

I don't think it would be too hard to make a fully parametric model of a grip in solid modelling software, fit that manually to the point cloud data - close enough anyway - and use that instead of trying to manipulate points and surfaces.

Chopping and changing a parametric model is an awful lot easier than moving surfaces from point cloud data around, and they can be ported onto different guns quite easily.

The smart way would be to build a parametric model of a hand and build the grip from that.

I make grips using a copy router (which I made for about $50 plus time) if I get some scanned (meaning to for ages...) I'll post the files.

JamesH wrote: I make grips using a copy router (which I made for about $50 plus time).

how did you do the copy router? Can you post some pictures of this? Does it work well?
I've been thinking about making one for ages but never got around to do it.

Thanks

Here you go. Ignore the Lady Gaga poster, it means nothing.















Basically its an X-Y sliding table as a base, with an upper panel with a router and a copy pin hinged a distance away to give Z movement.
X- and Y are free to slide, Z has a screw stop to limit the depth.

I'd suggest a 1/2" router is the minimum, long 1/4" tools are too flexible and chatter too much.

Its counterweighted so the load on the copy pin can be minimal. Its not possible to take huge cuts, the X-Y table has a lot of friction and could be made a lot better - but the friction also stops the cutter sucking the part in.
The ideal would be a smooth running table with brakes on each axis to allow contouring and controlled depth/width of cut.
There are two handles, one to move the table, one to help maneuver the guide pin/router over the part.

Typically I run backwards and forwards in the Y direction, and jog the X direction to give another cut. Go across the part taking a small cut in Z.
Then take a deeper cut in Z and repeat across the part.
If I'm prepared to take the time a usable grip can be had straight off the machine. Otherwise cleanup is needed to remove the pips between the contours.

I do the inletting with a separate router with guide bushings and various templates for each inlet.

One day I'll go the whole hog and buy/make a CNC system.

Home made power tools are dangerous! A 2000W router running at 20,000 rpm is not a toy. You've been warned.
The cutter will grab onto a screw/bolt head, unscrew the screw very effectively and pull it into the cutter. Brass screws are advisable.

The forces can be quite large, the grip being cut needs to be well fixed/chocked.

I have some CAD images I can put up if its not clear, maybe an edrawings model or parasolid.

Thanks James!

Those pictures make a great starting point.

Cheers

I was searching online and found these two models or router copiers. One for router and another for dremel tools.

Router
http://woodgears.ca/copy_carver/plans/index.html

And dremel

They're all the same principal, although rate of material removal on both would be very low. I wanted a system to take off 95% of the material in about half an hour.

I might make a light dremel type sometime for doing the final detail or minor mods - it can be useful to copy small features sometimes.
Dremels have a lot of axial float in their shafts, at least the ones I've used have, so they aren't going to be very precise.

There is a member, I think Jetter46 or somesuch, who makes grip kits for an IZH46 using a CNC mill.

He does not try to customize it to your hand, but makes a basic grip that is slightly oversized, so his machining gets you 80% of the way to a grip, but then you do the final 20% with a rasp and sandpaper (and filler, if you go too far).

I have not touched the technology of scanning in a while, but I do use solidworks, and having the design tree is critical to being able to tweek designs to get them right.

I think there is some mis-imagination going on here. As anyone knows who has tried it, you file some, you see how it feels, you file some more, you see how it feels, etc. You never have specific dimensions you file to and just know it will work first try - this isn't buying clothes, where you know that a 36 waist and a 32 inseam will fit. If you are trying to modify a grip in CAD, you need to 3D print something, see how it feels, modify it in CAD, make another 3D print, and so on, to get it right. That is unaffordable. Most likely, you'd 3D print once, then file and fill to get it right .... in which case the entire notion of scanning and CAD is wasted, because you could have started with a block of wood and had the same thing going for you.

The only other practical approach is to file/fill on something soft, like foam, and get it right, then scan and print it with zero modifications, so you take CAD out of the equation.

There is another approach where you design it in CAD, such that you have the design tree. You model it in foam and scan it, then tweak the CAD model to fit .... but at that point you are simply replicating the point cloud, so the HUGE work of building the cloud model seems wasted....

I agree it sounds like a fun project, I just can't see the justification, because this way is a lot harder than the Jetter approach, where you file to fit.