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Force Gage availability

Starting a new thread here so we can talk about the Force Gage tool rather than my experiments :)

I've decided not to try and monetize this effort; I retired from my work life for a reason; not looking for a new job. My desire is to make the tool available to anyone here who would like to have it.

Here are some things to consider:

Some hardware is required, a cost that, for the most part, cannot be avoided. The current parts price list I have built up, is $346.

A K&M press lists for $136 plus s&h. I have no interest in working on adapting to another press, but anyone is free do so.

The press will need one small modification. The top of the tower will need to be tapped 1/4-20, no need to drill, the holes are through-holes that run the full length of the tower, their diameter is correct for a 1/4-20 tap. Using 99% alcohol as a lubricant, takes 10 minutes or so to tap both holes. If I can do this, well, you know the rest of the story. Tapping these two holes in no way affects the normal use of the press.

Since it's fitted to an arbor press, that pretty much means a commitment to inline seating dies.

A decent PC is required. It doesn't have to be a raging fast, expensive rig. I run the software on an Intel Mobile-M processor which is no speed demon. Two available USB ports, or a USB hub required.

Microsoft Excel is really nice to have; it will work without Excel but the ability to save information and post-process it, will be lost. I could probably fix that but for now, it's probably cheaper to buy an older version of Excel on eBay.

The load cell MUST be calibrated. This is easy to do if you have a decent quality postal scale available. I have a 75lb capacity postal scale that works great. All that's needed to perform the calibration is a way to apply a constant force to the load cell as shown on the scale display, record the voltage reading for that force, repeat for 6-10 different forces, type those into a spreadsheet which crunches out a pair of coefficients, enter those into Force Gage one time, done. It sounds harder than it really is. I use a Harbor Freight $10 deep C-clamp to provide the squish force.

There are a couple of aluminum adapters needed to mount load cell and position sensors. I can either make those, or tell you how to. A piece of round stock and flat stock needed. Or, maybe you see a better, easier way to mount the sensors, even though I've spent hours trying to exceed my clever limits, someone else may see something I overlooked.

What's left is the software. There are three pieces right now; Force Gage (the tool), Force Gage Viewer for post-processing, and load cell calibration which simplifies the calibration process. Even though I'm happy to explain to anyone how make this work, it won't save time or money since mine is free, lol.

So there it is, figure about $400 and some shop time if you already have a K&M arbor press and inline dies, and a PC of course :)

Chris

Re: Force Gage availability

Reply #1
I'm interested but will probably wait until winter before I go off the deep end LOL
Dave

Re: Force Gage availability

Reply #2
Chris, definitely interested....count me in.   You are being very generous given all the engineering that you've put into it.
Bob
If everything seems under control......you're just not going fast enough

Re: Force Gage availability

Reply #3
Bob, I've learned more on this site because of the generosity of the folks here than I can assimilate in what's left of my lifetime :)

I'll start peeling the onion over the next few days so there's more clarity as to what's involved.
Chris

Re: Force Gage availability

Reply #4
Bob, I've learned more on this site because of the generosity of the folks here than I can assimilate in what's left of my lifetime :)

I'll start peeling the onion over the next few days so there's more clarity as to what's involved.

On the K & M press does it need to be the regular press or does it need the force pack? That's about all I'm lacking as far as press, dies and computer are concerned. Might as well get one found.
Dave

Re: Force Gage availability

Reply #5
On the K & M press does it need to be the regular press or does it need the force pack? That's about all I'm lacking as far as press, dies and computer are concerned. Might as well get one found.

Dave, does not need the force pack.

I'll post a picture shortly so we have an idea of how this all comes together.
Chris


Re: Force Gage availability

Reply #7
Below is a picture of a working Force Gage press. Sorry about the arrows and numbers, it's not easy to draw free-hand using a mouse pad :(.

1) Shows the tapped press tower. A pair of 6" 1/4-20 threaded rods provide the elevation needed to mount the linear position encoder. I used 6" rods just to make sure if I ever needed to raise the ram-to-base clearance to the maximum, I could. 3" rods, for all practical short-action cartridges should be ample.

2) Shows the piece of aluminum flat stock used to float the linear position encoder directly above the top of the press ram. It's 4-1/4" long with two 1/4" holes for the risers, two 1/8" holes to secure the encoder to the stock, and a single 7/16" hole which allows the encoder's shaft to pass through.

3) Shows the encoder, think of it as a super accurate tape measure; that tiny stainless steel draw wire is spring-loaded. Don't let it's awkward looks fool you, the thing is a technological tour-de-force :).

4) Shows where the encoder's draw wire connects to the top of the ram. The ram top is designed to hold a 3/8" indicator gage when used with the K&M Force Pack. The encoder's draw wire terminus fits in that spot like a hand in a glove, the same screw used to secure an indicator (10-20 I think), secures the draw wire.

5) Shows the load cell attached to the ram. The load cell is attached to the 1-1/4" diameter round stock piece with three M4 machine screws. The round stock is center-tapped M3 (or 4-40 if preferred), a corresponding M3 hex bolt is dropped down into the ram from the top until it exits the bottom of the ram, then screwed into the round stock. In other words, the load cell assembly is secured from above because the ram is hollow inside. Obviously, the load cell is assembled to the ram first, then the encoder is attached. It's simpler than it sounds.

It's noteworthy that an LC Wilson inline die has a screw hole in the top used for coarse seating depth adjustment. That presents a problem for the load cell since it has a tiny nub that must contact a flat surface. The solution is to thread a 1/2" long hex bolt into the die's top hole. It doesn't need to be wrenched, just hand tightened. It may be removed for further coarse adjustment. I'm sure there are other ways to make the die's top flat, this way works for me.
Chris

Re: Force Gage availability

Reply #8
Finally chipped my retirement work load down to where I could get back on fun stuff  ;D.

Below is a component price workup needed to build a Force Gage in it's present incarnation, this is for hardware only.


If anyone's interested, I'll order the parts, calibrate the load cell, make the needed fixtures, fully test the assemblies and mail them ready to bolt-on to a K&M press. Includes a link to hardware installation instructions, software installation instructions, software usage instructions, all software, all future software updates, and a picture of my dog :). Only thing I can't practically do is tap your press tower 1/4-20.

$420, PM if interested.

The workup includes links to phidgets.com where the sensors and computer interfaces are sourced.
Chris

Re: Force Gage availability

Reply #9
Chris you really should put a patent on that..
Grant


Re: Force Gage availability

Reply #11
Chris you really should put a patent on that..

Grant, I looked into a patent; it's a tall hill to climb. Government on the left, lawyers on right, alligators all around, lol.

Chris

Re: Force Gage availability

Reply #12
Climb it... if you dont someone will see this and climb the hill for you reaping the rewards..
Grant

Re: Force Gage availability

Reply #13
You know Grant, you are probably right, I'll put this on hold for now.
Chris

Re: Force Gage availability

Reply #14
Chris,  early in my startup days, we didn't have any money but wanted to protect our IP.  We used 'Legal Zoom' to file some provisional patents and it didn't cost us much and no other lawyers were involved.  However, at some point, if you want to go the full out Patent submission, then there are extra steps and cost.  But at least you are covered with the provisional for a year.

Bob
If everything seems under control......you're just not going fast enough