# Greg's French 75 Mm Field Artillery Model



## gjmontll

Upon my retirement two years ago, my first major project was to restore a 75 year old Logan 820 lathe. (See my "Greg's Logan 820 Restoration" thread.) While working this, several friends asked what I'd actually make with the lathe (and my X2 mill). I had some ideas, but nothing was firm.
Okay, after months of research, here's the planned project: create a detailed, scratch-built, scale model of the French 75 mm cannon, Model 1897.  Three motivating factors:

It's currently the centennial of WW I. Note: the first American shots were not fired until 23 October 1917, so I have 30 months to that precise 100th anniversary.
Those historic  first shots were fired by Battery C of the 6th Field Artillery. This was my grandfather's gun battery! So this project is in his honor. .
Given my machine-shop hobby,it's ideal topic, requiring research, design, prototyping, creation and assembly of numerous metal (and wooden) parts. [My grandfather loved working in his shop too, mainly woodworking. I'll be thinking of him, particularly while making the spoked wooden wheels.]
Why did the Americans use a French cannon? Apparently it was better than what we had available.With a unique recoil absorbing mechanism, it didn't need to be manhandled back into position for each shot allowing a "high" rate of fire. The US took the design and built them during and after the war, designating them the M1897 and several followup models.

First major challenge is getting accurate dimensions of the numerous parts.
Last week I visited the Camp Roberts Historical Museum, in central California, to see their M1897 hoping to get virtually all the measurements I needed. Unfortunately, their gun is a later version, a significantly-different M1897A3. And it was missing several important assemblies. I did get a better understanding of the breech mechanism, and a few useful dimensions. (My grandfather's history-making gun is in the museum at West Point.)

The Ordinance Department's _Handbook of Artillery _has some un-dimensioned drawings, but they do have a scale bar. So I shall to use dividers to extract the necessary dimensions on major pieces. Then the undimensioned drawings in the US Army tech manuals, TM-305 and TM-1305, and a French document will used to get the required dimensional details.

I also have a contact in France who had attempted a similar project. He gave me the contact info another Frenchman who did the cannon in Solidworks. Maybe he will share them with me? [Interestingly, all three of us just happen to be ham radio guys.]

 I'll use TurboCAD to first document the full-size gun, then to design the scale model.  (I need to quickly get way more proficient with TurboCAD!)

My model will be between somewhere between 1:10 and 1:5 scale. It is not intended to be an firing weapon, but I hope to have as many of the mechanisms operable as possible. These may include the wheels, brakes, elevation and train mechanisms, recoil assembly, and the breech/ejector/safety/firing assembly. 

I look forward to sharing my progress and problems with y'all.


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## gjmontll

Now that I've figured how to work our forum's new software to load pictures, here are a few images of the actual French 75 mm Modele 1897 that I am attempting to model.












75mm_mle_1897



__ gjmontll
__ Apr 16, 2015



						French 75mm in action
					
















FR_75mm_mle_1897_41



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__ Apr 16, 2015



						French 75 right rear view
					
















75mm_mle_1897



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__ Apr 16, 2015



						French 75mm in action
					
















800px-75mm1897BreechMechanismDiagram



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__ Apr 16, 2015



						French 75 and USA M1897 (all versions) Details of the breech and related parts
					




And finally, the M1897A3, that I saw last week at the Camp Roberts Historical Museum, at San Miguel, California. The "gun" itself is quite similar, but the "carriage" is significantly difference.












M1897A3  Front Left Camp Roberts



__ gjmontll
__ Apr 16, 2015



						US Army M1897A3 75 mm field artillery. Note: this is significantly different than the orginial...


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## w9jbc

that looks a whole lot like one on rodriguez range at camp perry ohio


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## gjmontll

So, it's been two months since I started this cannon project. What's been happening?
As I said in the initial posting, my first priority was to learn enough CAD to make some drawings. And then to extract/derive/estimate/... dimensions from some old American and French on-line documents. Here's a status update...

*Climbing the CAD learning curve*
In the 7 years or so that I've been doing home machining, I've tried a few different free or low-cost CAD packages on my home computer. I seem to have settled on TurboCAD, now have the Deluxe 2015 version. Over the past two months, I've struggled up the learning curve to the point that I think I can start the design work. I didn't fully appreciate the pros and cons of 2D vs 3D; [and still don't]. But I figured that since this was a very 3D project, I'd needed to be focusing making 3D objects in the CAD. Now it seems that while 3D must have its place, it doesn't work as well for making the fully-dimensioned engineering drawings one wants for machining. So, my focus is back on 2D and I've finally figured out enough to draw and print multi-view, dimensioned drawings.

*Finding the Dimensions*
My best resource for getting dimensions is _Handbook of Artillery _(HoA)_, _USA War Office, Ordinance Dept, Wash. DC 1920. It has a table of a few useful dimensions, e.g. barrel length, wheel diam and track width, and a few drawings that have a scale bar, accurate to +`- 5 mm. With these I have extracted some initial key dimensions that I can use to determine the scale of other, more detailed drawings in this HoA and other documents, such as the _Croquis du Canon de 75 Mle 1897, [_French Artillery School]. It has good colorized detail drawings, but no dimensions. So I am determining the scale of its drawings as I go, as well as Google Translate-ing its component labels. (I do speak some French_, _but certainly not a technical vocabulary.)

*The Question of Model Scale*
How big will my model be? I had guessed something between 1:10 and 1:5 scale. I want it as big as my current machine shop will allow and think the 25/32" spindle bore on my Logan 820 lathe will be the limiting factor. And this limit will be in the drilling (and boring?) of the barrel. At a 1:8 scale, the barrel will be 12.795" long, with a muzzle diameter of 0.565 and a breech diameter of 0.787. That latter number is 6 thou too big to fit through the spindle, so I'll have the breech end in my 4-jaw chuck. BTW, the bore will be 0.369. That's the plan!
*Starting to Cut Metal*
Before tackling the barrel, I want to start with something easier, but one that will drive other dimensions. I think the axle is a good choice, and it's a challenging piece in its own right. It has acme threads in its interior (for the gun's traversing drive) and tapers at each end for the hubs of the big wheels. And these tapers are not concentric with the axle's cylindrical axis, they are slanted downward to give the wheels a positive camber. I think I can machine this axle with its tapers as a single piece, adapting the technique that we'd use in turning a crankshaft, with a true center and offset center(s) at each end. This axle is approximately 0.369 OD (same as the barrel bore) and 8.809 long.  Tonight I'll draw the plans and tomorrow start cutting.

Greg


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## gjmontll

*Starting on the First Part (Try #1) - Lathe Issues*
Rather than the complex machining of the axle with its end tapers, I simplified my design and will make it with three pieces, the main axle and two cambered, tapered ends. I'll connect them with split pins for now, then perhaps braze the joints. Having made the CAD drawing, I started the machining, using a 5.5" piece of 3/8" steel.
But I haven't used the lathe much since last year's overhaul and two problems cropped up. The tailstock is off-center - okay, simple enough. And I single-point cut the 3/8-16 thread. It looked good, until I ran a tap over it and found it was actually 20 TPI. The QCGB was set to 16! What could be wrong? Going back to the photos I took of my Logan 820 before I did the overhaul, I now see that the gear at the end of the leadscrew is in the inboard position. It needs to go outboard - this now explains the problem I posted about when I couldn't get the change gear stop bracket back in proper position. Since the gears and gearbox all seemed to work, I left it off! 

*Today:*
I will align the tailstock, fix the gear positions, and try again.


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## gjmontll

*07Jun15  Making the First Part - Main Section of the Axle*
Okay, with the lathe geartrain now correct, and the tailstock aligned, I retraced yesterday's workflow and made the central section of the axle, at 1:8 scale to the original.
I compromised on a few details, using a UNC 3/8-16 thread instead of a metric Acme one, and massaged the diameters a bit to mate up with the thread's major and minor diameters. I still need to mill a long keyway on it.
I picked the axle as a good starting place, since it's the connection point of several other assemblies. The wheels, shield, wheel brakes, mount for the recoil brake, traversal mechanism, and trail all connect to the axle. [The "trail" is the long spar that extends to the rear. The back end has a "spade" that digs into the ground to anchor the gun, and when lifted up, has the towing ring.]
Next up will be the cambered tapered ends for the axle, onto which the wheel hubs mount.
   Greg


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## gjmontll

And finally, the first part is done. Actually, the axle, as with the real gun, is a three-piece assembly. I had previously shown the center piece, with its threads. Onto each end go the tapered, cambered hub spindles.


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## T Bredehoft

How have you registered the two tapered ends to each  other?  You've shown a remarkable ability and determination. Keep us informed.


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## gjmontll

Tom, thanks for the encouraging words. 
You're just seeing the good stuff, it's been frustrating making these first few pieces. And now, I think I made the tapers about 1/4" too long and will have to redo them. But first I will do the CADrawings for the hub pieces the tapers must mate with. These two wheel hubs are each two-piece assemblies, each of which have both internal and external tapers. Cutting the external ones are straightforward enough, but the internal taper are too small (0.200) for my smallest boring bar. I'm thinking I'll try to make a D-bit style tapered reamer specifically for these hubs. I'll make these pieces from a perfectly sized piece of 1.375" aluminum rod in my scrap bin.

Not sure I totally understand your question, but the tapers aren't "registered to each other", rather, to the central piece, which is essentially cylindrical and axially drilled at each end for a 1/8" split pin. On the tapered end pieces, it's not the taper that make it tough; it's the 14 degrees of downward camber angle. 
Here's how I did it, using two different axes. 
   First, the offset, or camber axis: the inboard end had some extra 1/2" of sacrificial material, this allowed me to hold the taper in the chuck. I drilled an center hole, offset from the true center by 0.040, at the inboard end of the spindle, into the sacrificial material that would be trimmed later. The outboard end had a on-center center hole. I turned the taper between this offset pair of centers (with the tailstock offset to give my required taper). 
Then, in the 4-jaw chuck (centered this time, not offset), I removed the offset hole and drilled a new hole (with the tailstock back in alignment with the spindle) for the split pin, on-axis, going through the sacrificial section and into the taper (but off-axis to the cambered taper section). Finally, I cut off the sacrificial section and milled a camber-matching 14 degree bevel onto the inboard end. Finally, connect the spindle with the axle with the split pin. 
And repeat all this for the other end. 
I hope this verbal description of my workflow answers your question.
     Greg


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## gjmontll

*8 July 2015 - Making tapered D-bit reamers for the cannon's wheel hubs*
Each of the two pieces of the wheel hubs have an external taper and an internal taper and a flange with 7 holes. The internal taper of the outer hub flange seats on the external taper of the inner hub flange. The 7 wooden spokes will be clamped between these flanges by 4-40 bolts. 
These tapers are 2°, so I set the compound to 1° and cut the external taper for the outer hub flange then made the tapered reamer from 1/2" drill rod using the same setting.  I then milled the D-shape into the tool, and milled a hex head on the other end.  Used a propane torch to harden it and tempered in the oven at 435 for an hour. It sharpened up nicely and did a nice job of reaming the aluminum flange pieces. (I used aluminum since I was worried how well my home-made reamer would work on steel. Now that I am done with its intended purpose, I'll try a test cut on steel. 
On to the second taper, this time with 3/8" drill rod. It's tempering in the oven now. 
Tomorrow, with the lathe's compound still at 1°, I'll turn the inner flange pieces, then into the rotary table (gluing them to wooden spools) for the seven 0.116 holes and the reaming.
Below pictures:
  1. The two outer hub flanges and their tapered reamer.
  2. Having turned the taper in the lathe, here I'm milling away half of the taper to make the D-bit. That's an adjustable parallel supporting the bit's tip.
  3. The outer hub flanges were glued to wooden dowels to hold them in the rotary table for drilling the bolt holes.
  4. Then the outer hub flanges were flipped over and screwed back onto the spools for having the central hole reamed. 
  5. Having been turned and milled, the second D-bit is being hardened. (It's O1 Drill Rod.)


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## gjmontll

*Wheel hub flanges - done!*
This photo shows the two wheel hubs, now completed. The pieces are sitting on their corresponding page from the French Army document that was primary source for my CAD work for these components. I tried to come up with a good machining sequence on these parts, but I should have left more material on the ends for holding in the chucks. The tapered D-bit reamers featured in the prior posting worked well, as the inner hub mates nicely to the axle taper, and the outer flange onto the inner flange taper.
Next up:  Maybe I can find a few more straight-forward piece to design and build. So far, the axle and hubs have been challenging, maybe I can do a few simpler pieces while I design the wooden pieces for the wheels. (each hub mounts 14 spokes that connect into 7 wooden "fellows".) Then there are numerous small metal brackets and fasteners that tie the spokes and fellows together and a steel "tire"
around the rim.
   Greg


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## Moose53

gjmontll said:


> *Wheel hub flanges - done!*
> This photo shows the two wheel hubs, now completed. The pieces are sitting on their corresponding page from the French Army document that was primary source for my CAD work for these components. I tried to come up with a good machining sequence on these parts, but I should have left more material on the ends for holding in the chucks. The tapered D-bit reamers featured in the prior posting worked well, as the inner hub mates nicely to the axle taper, and the outer flange onto the inner flange taper.
> Next up:  Maybe I can find a few more straight-forward piece to design and build. So far, the axle and hubs have been challenging, maybe I can do a few simpler pieces while I design the wooden pieces for the wheels. (each hub mounts 14 spokes that connect into 7 wooden "fellows".) Then there are numerous small metal brackets and fasteners that tie the spokes and fellows together and a steel "tire"
> around the rim.
> Greg
> View attachment 107293


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## Moose53

I am watching your project with great interest . You appear to have access to workable build drawings of the French 75 . I am a member of the GBO forums and enjoy building operational 1800's artillery . Tracy and Mike at seacoastartillery on GBO forums may be able to provide you with a scale rifled tube for your project .


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## gjmontll

Moose53 said:


> I am watching your project with great interest . You appear to have access to workable build drawings of the French 75 . I am a member of the GBO forums and enjoy building operational 1800's artillery . Tracy and Mike at seacoastartillery on GBO forums may be able to provide you with a scale rifled tube for your project .


Thanks for your interest. 
The French drawings are good, but to call them "workable build drawings" is a stretch. Since they are only drawings, lacking dimensions, accompanying text, or any designation of scale, I wonder what their purpose was.  Different pages are obviously at different scales, so I derive their scale based on some known dimension(s), then go from there.  For example, the axle/wheel drawing shown in my last posting appears to be at 1:7 scale. So I measure each feature as closely as possible, then multiply by 7/8ths to get the size for my 1:8 scale model, drawing in TurboCAD. Since the French drawings have no dimensions or scale, I'm designing and building in inches. 
I was unaware of the GBO forums until you mentioned them, they look interesting, but just looking at the list of fora titles, I didn't see anything exactly applicable. Am I missing something?
And I looked at Seacoast Artillery's website. Impressive products. I'm sure they could make a custom barrel for me. However, I want the major pieces to be my creations, and to as much as possible, the minor parts too. (When possible, I may purchase some gears and will purchase most nuts, bolts, rivets ....) But I will ask them about the barrel, maybe I can machine it and have them rifle it, or a barrel liner.
What sort of 19th century artillery do you make? You say operational, what scale? As I researched my project, I see all sorts of other interesting project ideas. As you may know, the French 75 Model 1897 was considered the "first modern" field artillery, belonging more to the 20th century. It's a much more complex project than I should have undertaken, but as I said at the start, this is because of my grandfather's involvement with the AEF's "First Shot."  
Back to the machine shop, 
     Greg


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## Moose53

gjmontll said:


> Thanks for your interest.
> The French drawings are good, but to call them "workable build drawings" is a stretch. Since they are only drawings, lacking dimensions, accompanying text, or any designation of scale, I wonder what their purpose was.  Different pages are obviously at different scales, so I derive their scale based on some known dimension(s), then go from there.  For example, the axle/wheel drawing shown in my last posting appears to be at 1:7 scale. So I measure each feature as closely as possible, then multiply by 7/8ths to get the size for my 1:8 scale model, drawing in TurboCAD. Since the French drawings have no dimensions or scale, I'm designing and building in inches.
> I was unaware of the GBO forums until you mentioned them, they look interesting, but just looking at the list of fora titles, I didn't see anything exactly applicable. Am I missing something?
> And I looked at Seacoast Artillery's website. Impressive products. I'm sure they could make a custom barrel for me. However, I want the major pieces to be my creations, and to as much as possible, the minor parts too. (When possible, I may purchase some gears and will purchase most nuts, bolts, rivets ....) But I will ask them about the barrel, maybe I can machine it and have them rifle it, or a barrel liner.
> What sort of 19th century artillery do you make? You say operational, what scale? As I researched my project, I see all sorts of other interesting project ideas. As you may know, the French 75 Model 1897 was considered the "first modern" field artillery, belonging more to the 20th century. It's a much more complex project than I should have undertaken, but as I said at the start, this is because of my grandfather's involvement with the AEF's "First Shot."
> Back to the machine shop,
> Greg


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## Moose53

It will take a while to get used to how this forum works so please excuse the extra posts. I have to wait a bit more before I can post links to some of my cannons . Because I know how easy it is to set this up as a operational piece I would make a suggestion. Because of the complexity of this project you could make the wow facture over the moon if you could model it in 1/3 scale with a bore of 1 in . Because the ATF considers any artillery piece made before or during 1898 an antique you should have no problem getting it ok'ed . I would be more then happy to show you some ways to make it shoot and even how to make cases . No one I know of has been able or willing to tackle the French 75 because of the complexity or lack of workable information . So you can understand our enthusiasm , if you are unable to make a shootable model , someone here will be able to with your helpful information . Thank you


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## Onit12345

Here's the link for GBO cannon section

http://www.go2gbo.com/forums/blackpowder-mortar-and-cannon-sponsored-by-seacoast-artillery/


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## gjmontll

Thanks to Moose53 and Onit12345 for your interest and the info you've provided. 
That URL in the previous message is very useful, interesting to see how the Seacoast experts do their barrels. And it led me to two other sites that I was not yet aware of:
http://passioncompassion1418.com    General WWI artillery info, (with English translation pages available)
http://canonde75.free.fr/index.htm      Dedicated to the Modele de 1897 (only in French), this looks like a great resource, pictures, diagrams and descriptions on various assemblies. I know enough French that I can (with the help of Google Translate) make good use of their info. And their list of surviving 75's says there is one just an hour away, in Santa Ana, CA. Another field trip in the offing after I find exactly where it is. It is supposed to be an actual 1897, my April trip to Camp Roberts revealed a US Army later model, as I posted here a few months back.
My plans remain unchanged, I am endeavoring to make a 1:8 scale non-operational replica.


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## gjmontll

*Status Update: Axle, Wheel Hubs, Sleeve*
I've been doing some rework. My original set of hub spindles were too long and I needed to redo one of the hubs. Rather than that complex process for turning the spindle taper at the camber angle that I did first time, I turned the taper using the compound slide set to 1°. Then I heated and bent the spindles for their 3° of camber. (Made a bending fixture by drilling and reaming the spindle taper into the end of a piece of 1/2" steel rod. I was pleased to see that my homemade dbit reamer worked fine on the steel too. If I had known that, I'd have made the hubs from steel, not aluminum.
In my 19June2015 posting, you can see the axle, and see that the diameter is different at each end of the threaded portion. The larger diameter is actually the major diameter of the threads, and the smaller diameter matches the threads' minor diameter.  This is how it is in the real gun,  I believe it is to facilitate assembly and maintenance. After installing the axle into the trail, a sleeve then shims the narrower portion back out to the major diameter. On the full size gun this sleeve would be a substantial piece of metal. But at 1/8th scale, I worried about being able to drill a 0.297 hole through a 1.125 inch long 0.368 steel rod. But that is close enough to 3/8" that a 3/8" collet still holds it and would hopefully be less likely to crush the thin walls than my lathe's 4jaw chuck. But it went well, as shown below.
Pictures: 
1: Drilling the axle sleeve, holding in a collet vise on the lathe.
2. The assembled axle, with its spindle tapers and the sleeve, and the two wheel hubs. Notice the 3° camber, (it looks like it's more.)
3. Separate parts: axle with spindle tapers, wheel hubs.
Note: Laying parts on the French drawing, they look a bit small. That's cause the drawings are 1:7 scale, my project is 1:8 scale.
\
Now I'm almost ready for the woodworking part: making the 28 spokes and 14 fellows. I should design/build some jigs and fixtures for the odd angles involved.
   Greg


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## sanddan

I just found your build, great work so far.

There is a technic I used on SolidWorks that could help you with translating the non dimensioned original drawings into at a minimum 2D and possibly 3D solid models. PM me if your interested. Not trying to disrupt the build.


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## gjmontll

*Status Update: Wooden Wheels in progress*
For the past few months I've been working on the cannon's wooden wheels. As the image in my prior message showed, these are fairly complex assemblies and I've been feeling my way through the process.
 I need to produce 42 wooden pieces, the 14 spokes and 7 fellows for each wheel. ( A "fellow" is a segment of a wooden wheel's rim.) I have finished the basic shaping of the fellows. 
Each spoke fastens to the fellow with a small steel spoke-shoe. I just finished the milling of these 30+ shoes (I have a few spares.), each requiring about 12 milling operations (plus hacksawing and hand filing). I quickly recognized the productivity value of a vise work stop, and took a break from the wheel work to make one that proved very useful. Below is the work stop in action as I machine a spoke shoe (center drilling for the 0.063 hole used to bolt the shoe to the fellow.)



So far, I have done one prototype spoke. Each spoke will be formed from a 0.5" x 0.36" x 2.8" piece of oak and requires about 12 machining operations. Because of the small size and odd angles, ordinary woodworking tools (sander, router, jigsaw) don't seem to work well enough. Given that I need to make about 30 spokes, I need to get a more productive process going. Based on my prototype, the first step will be on the metal lathe, the rest on my mini-mill/drill, several cuts using a router bit. The oak machines nicely, except for the sawdust. Because each of the four long faces have two different angles, I plan to make a set of fixtures that will position the spoke in the mill vise in all the needed positions. (Or maybe use my sine-vise.)

Below is another image showing a  wheel mockup with a set of fellows temporarily held in place with a hose clamp, and the pile of spoke shoes. One shoe is assembled on the prototype spoke which sits in place in the wheel hub. The bottom four shoes, adjacent to the dime, show the shoe from top, bottom, left and right side views. 




Not yet started are small steel joining plates that connect the fellows together. And I haven't yet figured how I will weld a strip of 14 gauge steel to form the tire.

From the gun on display at Orange County, here is the real-world object showing spokes, shoe, plate, fellows, and fasteners. As you see, this gun is painted gray and black. I haven't yet decided on the finish for mine. To be historically-correct, it should be a green/brown/white/black camouflage pattern. But I don't want to obscure the mechanical details.


This week I hope to finish the spokes! I'll be glad to get the woodworking out of the way.
     Greg


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## gjmontll

*Making the Wooden Wheels*
For 4 months now,  I've been building the cannon's wooden wheels. Not quite done, but yesterday was a milestone: a success test fitting of the spokes, shoes, and fellows that I've been working on.  

*Fellows*: 
Each wheel's rim is made from seven fellows (aka "felloes"). They were cut from 1/2' oak and sanded to match the template of my CAD drawing.  Each fellow connects to two spokes using steel spoke shoes. Rabbets for the spoke shoes were done on the mill, using a router bit and hand holding/guiding the pieces. 

Fellows1  The oak pieces after cutting on Rockwell BladeRunner table-jig saw.



Fellows2  And after cutting/sanding the curved faces.



*Spoke Shoes*
The wooden spokes connect to the fellows by use of a steel spoke shoe, bolted to the fellow. 
These shoes were machined from 3/8 x 3/8" steel key stock. Making 28 of them, plus some extras was tedious, with about 20 machining operations to do on each shoe. 
I improved my process by spending two days to make a mill vise work stop with plans from a great website I'd not known about, see  http://www.homemadetools.net/
Still tedious in the multitude of openings and closing of the mill vise, but then  doing the work in an assembly line fashion greatly improved my speed and accuracy.

Spoke Shoes 1


Mill work stop: built from plans on HomemadeTools.net, but to half-size.


Spoke shoes 2


Spoke Shoes 3


Machining Spoke Shoes Workstop



*Spokes*
The 28 oak spokes were the toughest part yet to make. 
Each one has a 3/16" stud or boss on the end to fit into the shoe. This stud is on-center radially, but off-center axially, to implement the outward dishing of the rim from the hub. These oak studs were turned on my metal lathe, using a 4-jaw chuck and metal cutting lathe tools.
Then the mill was used to cut several different tapers on the radial and axial faces. A sine vice was used for the angles, but as the photos show, because of the small size of the pieces, I clamped them in a small vise, held in the sine vise.  These cuts were made with a router bit in the mill, running at my mini-mill's 4300 rpm top speed. (I have Little Machine Shop's Belt Drive Mod kit.)
After milling (routing) all the tapers, I made a fixture to hold the spoke for the cutting of two arcs into each of the axial faces. My normal mill vises don't open wide enough to hold the fixture, so I again used my sine vise, just because it opens wider.One arc is to start the tapering after the spoke leaves the hub. The other is for the #2 bolts that holds the hub and spokes together.
:
Spokes 1  The first of nine routing operations was a rabbet, sine vise not needed.


Spokes 2  The 28 spokes, shoes, and one spare.  I ended up having to make more blanks and take them through the lathe and milling/routing process.



Spokes 3   Note the small vise being held in the sine vise for routing one of the six taper cuts.


Spokes 4 Spokes, shoes, fellows and hub laid out on the CAD drawing, showing both axial and radial faces of the spokes and shoes.


Spokes 5  This is the fixture to hold the spokes for more routing operations


Spokes 6  Fixture in use for routing arcs in the axial faces of the spokes.



*Wheel Progress and Test Fittings*
The first test fitting showed the spoke were interfering with each other inside the hub flange, thus the circumference was too large, causing the gaps between some of the fellows. Today I sanded the spokes' hub taper and retried it. Much better, although I need to fix the angle on one of the fellows, or use a spare.

Wheel Progress 08 Nov:  Fellows have not yet been rabbeted to accept the shoes.



Wheel Progress 22 Nov   Testing the fit with a rabbeted fellow and two spokes



Wheel Test Fit 1a  28 Nov    Now with rabbeted fellows, a full fitting. Note the gaps between some fellows. The spokes are not fully seating into the hub...


Wheel Test Fit 1b   28 Nov  With the hub's outer flange removed, the cause of the fellow gaps is seen, need to adjust the tapers where the fellows abut against each other.


Wheel Test Fit 2  29 Nov    After sanding the spoke tapers,  now it fits! But still more to do, as listed below.




Remaining wheel work
Fellow splice plates: I've only completed the CAD. Need to make 14 plates out of 26 gauge steel. See photo of real wheel fellow with its plates and shoes. 



Fellows: drill the holes for the spoke shoe bolts, rabbet for the fellow splice plates, and drill holes for the tire and splice plate bolts.

Spoke shoes: round the corners with a file or grinder.

Spokes: Mill (or sand) a chamfer on each of the spoke edges. Some final finishing sanding and they will be done.

Tire: A steel hoop of 14 gauge steel needs to be made, probably by brazing. After heating and shrinking it onto the fellows, holes for #0 flat head bolts need to be drilled (and countersunk) through the tire and the fellows matching up with the fellow splice plate holes. I'm worried about getting just the right circumference for a proper fit.

Finishing: I am undecided on the color scheme. It will probably follow my grandfather's historic "First Shot" gun which is now at West Point''s museum. This is a camouflage pattern of browns, greens, and black. From the online photos I see, it looks like the wheels are just painted a solid brown.

Question to the Forum: Is anyone close enough to West Point that they could get me some really good photos of the actual coloring? And of mechanical details when I need more info. That Orange County Courthouse gun is 1) not camo painted, and 2) is missing some pieces.

right side view wheel at the Old Orange County Courthouse, Santa Ana, California



That's all for now. I hope to complete the wheels this month.
      Greg


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## CNCMAN

looks great.


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## Rick Berk

OUTSTANDING. When I made a set of tires for a cannon I made, I used a piece of 5/8 plate and hole sawed the middle out then back to the lathe for boring. My final width was .400 so my tire material being .625 I tapered one ID leading edge about .200 deep and bored the tire .020 undersized. When assembling I made a jig and pressed the felloes and and spokes into the tire, the results were worth the effort on tightening everything up. Then back to the lathe to final trim to width and removed the taper used for assembly. I then made another jig to sandwich the hole wheel in the lathe and turned to OD. Hope this gives you an idea as I spent 6 months figuring this out 40 years ago.


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## gjmontll

Rick, 
   That taper is a great idea.  I have been considering a similar "saw/turn/bore it out of 3/8 plate" but hadn't considered the taper. At first reading, I didn't quite understand you, but now I think I do -- basically you included a temporary funnel to guide the pieces together, then machined it off once the parts were mated, right?

I did look at my favorite local scrapyard for some appropriate raw material for this approach but found nothing. At home the other day, I saw a small barbell weight plate, but it was not quite the necessary 6.525" OD. (And it was cast iron; it would be messy machining, but that's not a showstopper.) Since I already have the 14 gauge steel ready, I may first try the more traditional method this week, bending and brazing. Even this approach could make use of the "temporary guide funnel" approach. 

Yet another idea just occurred to me: that large hoseclamp I showed in my last posting, holding everything together in a test fitting .. I think I could overtighten it a bit (flexing the spokes) to shrink the wood OD enough to get it started into the tire, even without a taper. And heating the tire will help a bit too. I need to do the math on that to see how much expansion I can get.

Or I may just enlist a professional welder for advice / assistance.
   Thanks, 
       Greg


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## Rick Berk

First paragraph is correct, Second paragraph don't use cast iron it will break and barbells are made from CI that cant be used for anywhere else. Last paragraph Shrink fit will not work for this thin material. Brazing or tig welding will greatly soften the metal at the joint leading to all kinds of alignment and diameter control. Look forward to the rest of you build.


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## gjmontll

Rick
Okay, I will defer to your experience and recommendations on this and very thankfully forget about the "bend it and braze it" method. 
For my project, the tires will be much easier, they are almost a standard off-the-shelf size. 
My cannon's steel tires need OD/ID of 6.52/6.43. 
Luckily, Schedule 40 6" pipe OD/ID is 6.625/6.065. 
... so no massive metal removal is needed.​I've just ordered 4 slices of 1/2" thick pipe from SpeedyMetals.com.  
Why 4 slices? If everything goes well, I'll have two tires for the cannon and two for its companion limber, if I decide to built it. (I already have some spare spokes, spoke shoes, and fellows in various stages of completeness.) 
More likely, the extra slices will be expended in making two good tires. I am concerned about holding the piece tightly enough in my 4-jaw to prevent slipping but not too tight that it deforms the radius. . Too bad my faceplate is only 6" OD, but I'm sure I can figure some sort of fixture to assist in this. (And take very light cuts.)
Greg


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## gjmontll

*Wheel Assembly - End of Year Status*
I wanted to get the wheels done by the end of the year. Didn't quite make it!
Today I began the trial assembly, bolting the spokes into the hub and fellows for the first wheel. This is just an initial assembly to check the fit and get a final reading on the critical outside diameter prior to making the tires. Those are #0 nuts and bolts on the shoes and #2s through the hub. Again, 7" hose clamps are in use to hold the fellows in place during assembly.


After my request for some Forum member near West Point, Tino volunteered to visit the Museum for me and get some good photos, concentrating on the color scheme. I called the Museum before Christmas and spoke with the Arms Curator to arrange VIP access for Tino. He was very receptive to my request. On the colors topic, he told me the guns came from the factory with the camo already done, I had assumed it was done in the field by the soldiers, 
So far, my parts have had initial primer coats.. When completely assembled, I'll top coat with the correct shade(s) of camouflage paint.

Not shown in this picture - the fellow splice plates that will be bolted at each fellow-fellow joint. I've already drilled their holes through the fellows. Once the tires are on, I then need to remove the spokes in order to get drill access to continue the splice bolt holes out through the tire. Then countersink for 14 #0 flat head bolts that will go thru the tire, fellows, and splice plates.

For the tires, per Rick Berk's suggest (see the 13, 14 December postings), I have my 1/2" slices of 6" Schedule 40 steel pipe ready to go, this week I'll put them in the lathe and turn* them into tires. (*Pun intended).

Happy New Year 
     Greg


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## gjmontll

*Wheel Construction Finished*
The woodworking is now done and the wheels (hubs, spokes, shoes, and fellows) have been assembled.
I set them up in the mill on a pivot to true the outside diameter (first photo). In this configuration the fellows and spokes are not fully-constrained. It took an elaborate setup (1-2-3 blocks to either side of the cutter and the arm of my mill work stop on the left side of the mill) to adequately stabilize the fellows for the cutting with a 1/4" router bit.  


Then I put the hose clamps back and tightened down. As shown in the second photo below, as it's compressed, the spokes tilt outward and the gaps between the fellows come together as the wheel assumes its final shape. Now I can measure the final OD, 6.50".  This will be the inside diameter for the steel tires, which I will make today,  
Below are the two wheels, on their axle. You see the positive camber since the axle ends bend downward. The rabbets, slots and holes at the fellow joints will be filled with splice plates and #0 flat head bolts. 


In the foreground are the 1/2" slices of 6" Schedule 40 pipe that will become the tires.They already have an almost perfect OD, just a light finishing cut should be needed, then  I'll bore it 0.148 and cut the guide ramp, following the technique Rick Berk mentioned here 3 weeks ago. 
   Greg


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## wrmiller

Cool stuff.


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## gjmontll

*Axle needs a keyway*
Yesterday afternoon's shop session was an exercise in frustration as I tried many ways to hold the axle in the mini-mill. My little Sherline vise can sit on its back face, but I was unable to get it clamped down adequately despite two hours of experimenting.  Figured that I'd need to make a custom fixture, to hold the axle by split pins in it's ends.
But as I cleaned up my shop, I had the brainstorm to use one of my lathe's AXA toolholders to hold the 3/8" x  4" piece on the mill. Today I did it, and it worked very nicely. I used a 1/32" slitting saw for a 1/32" deep keyway.
This slot goes through both the plain and threaded portion of the axle.  The keyway and key are used to keep the axle from turning when the traversing mechanism is operated. Instead the rotary motion is converted to linear motion, jacking the gun carriage left or right along the axle to aim the gun.


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## FOMOGO

Very nice work. You are an amazingly patient man. I probably would have committed Seppuku by now. Mike


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## gjmontll

*Wheel Construction Finally Done!*
After six months making the cannon's wooden-spoked, steel-tired wheels, I'm finally done with their construction. I have finished with the woodworking! Now just good old metalworking.

Just need to do the finishing paint, a yellow-green acrylic. Thanks to hobby-machinist Tino doing a January photo recon mission to the West Point Museum, I have all the detail needed to match the original camouflage scheme. As I've mentioned before, this museum piece  is the very one that my grandfather's gun battery used to fire the first American shot of WWI. So now I can start painting, the wheels will be a solid olive drab color. Talking to the museum's Arms Curator, I was surprised to learn the guns were camo painted at the French factory in a standardized manner. I had assumed it was more casually done in the field.  Here is a link to Tino's package of 172 photos:      https://www.flickr.com/photos/133495471@N08/sets/72157663157435569/  I'm in the process of compiling a table of contents/list of captions/cross reference to the images.

Again, I thank Rick Berk for his December 13th suggestion in this thread. He recommended not making the tire from bent and welded 14 gauge  steel sheet, but to cut it from a solid plate and make it extra wide, then use the extra width to make an entry ramp. This would facilitate squeezing the wooden felloes down snugly into the tire. In my case, 6" Schedule 40 was almost the perfect OD! To minimize mucho metal munching, I ordered a few 5/8" slices of the pipe. For each slice, I bored it for the wooden felloes' OD and added the tapered entry ramp. This worked beautifully, after pressing the hub/spoke/felloes assembly into the tire, I put it all back in the lathe and cut off the ramp. 
Each wheel assembly consists of 143 pieces. The tire, fellow, and spoke shoes are fastened with #0-80 hardware, the spoke/hubs are fastened with #2-56. So far, all stainless steel, since that was the only material I could find that came in the sizes needed. (I used www.microfasteners.com)


Wheels on axle, ready for painting


   Wheel hub details, next up, making the lynch pin.


    Using jig to cross drill the axle for the lynch pin. 
As you can see in the attached images, I have made the castle nuts (#8-32) that hold the wheels onto the axle. Today I made a simple jig to hold the axle thread ends as I cross-drilled them to 0.055" to accept the lynch pins. 

The French Army drawings that are my primary reference source didn't make it clear how the lynch pin assembly worked. So I asked Tino to get some good detailed images of these, which he did. Now I need to figure how I'm going to make them.

As before, every single piece on the project has had its complications in design and implementation! That's what makes _model engineering_ such an challenging and engrossing hobby.

Greg


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## gjmontll

*Cannon Project Status Report - Lack of Progress
*
I haven't posted anything in a year, 'cause I haven't made any significant progress.  I'm certainly not going to be done in time for the centennial of "The First Shot".

Last spring, I was working on making the wheel lynch pin assemblies. Spent two days with much filing and the result was a case of "trigger finger" - inflamed middle finger tendon. 
This basically kept me away from the workbench for months. It might be healed now, but I suspect I'm susceptible to re-injury.  

And problems with my CAD. As I've mentioned in my posts, the lack of dimensioned drawings means having to make my own, based on old French and US Army drawings (from tech manuals, not engineering drawings), and from my photographs, measurements, and sketches of actual guns. I had been using TurboCAD, and with much struggling, did have some success, but at a very low productivity. 

Then I discovered Autodesk's Fusion360 and was very impressed. I have started using it to layout the gun's trail, but I really need to become more proficient. I was only familiar with 2D CAD, and only familiar, not really proficient.

Fusion360 is powerful, but complex. My efforts to learn it have been intermittent. There are various online tutorials, and in general they are good at what they are trying to show. But I really wish there was a reference manual. (From what I see on the users' forum, apparently many others agree.) But there really isn't!  I am considering writing my own manual! BTW, I think TurboCAD's documentation is inadequate as well.

After I get our taxes done, I will really get back to work somehow. Rather than tackling another critical, complex part, I think I'll find some "low-hanging fruit", maybe parts of the shield. If I can't get a nice engineering drawing out of F360, I can just make hand sketches.

     Greg


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## Rick Berk

Hello Greg, I was wondering what happen to your build, sorry about your hands, I too realize that using my hands as a hammer on a milling vise was not the smartest thing, but quick and easy at the time. I remember when our company bought Pro E for all the draftsmen and within one year half of them had quit due to the stress of an old dog learning a new trick. I still do all my work on a envelope with a soft lead wood pencil. Looking forward to you making smoke some day.  Regards.


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## gjmontll

Rick Berk said:


> Hello Greg, I was wondering what happen to your build, sorry about your hands, I too realize that using my hands as a hammer on a milling vise was not the smartest thing, but quick and easy at the time. I remember when our company bought Pro E for all the draftsmen and within one year half of them had quit due to the stress of an old dog learning a new trick. I still do all my work on a envelope with a soft lead wood pencil. Looking forward to you making smoke some day.  Regards.



Thanks Rick, 
My finger injury was caused by hours of filing using needle files that had no handles. Hopefully the wooden handles I made for them will prevent re-injury. 
The only smoke I expect to make related to this project will be from welding, brazing, and hot cutting oil. Unless my plans change, this will be a non-firing model, but operable in as many details as possible. (e.g. operation of breech, elevation and traversal mechanisms, recoil mechanism, and brakes. If it was to be fire-able, I suppose I could design as chambered for something around 0.38 calibre. But I doubt a properly scaled firing spring and pin would have enough impact to ignite the primer.
  Greg


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## peter orchard

Hello Greg I see you are building a scale model of the French 75 I have beennasked to build a barrel and recouperator assembly to go on a original carriage and was wondering if you hadva set if drawings available 

Sent from my SM-G960F using Tapatalk


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## gjmontll

peter orchard said:


> Hello Greg I see you are building a scale model of the French 75 I have been asked to build a barrel and recouperator assembly to go on a original carriage and was wondering if you hadva set if drawings available
> 
> Sent from my SM-G960F using Tapatalk


Hello Peter,
 As you probably saw, I haven't posted any progress on this thread in 4+ years. Health issues, family stuff, and other interests have taken priority, but it's still on my mind.

You've probably read through my thread of posts on the M1897 and seen my mention that lack of machinist-ready drawings has been a major stumbling block. So I have to CAD my own drawings, and have stumbled from one CAD platform to another. That's a different problem. 

My best source of info is a French document. I'm not sure what the actual purpose was, but its drawings, labelled in French, show most of the detail. Unfortunately, they lack the dimensioning needed to recreate the parts and they lack any indications on their scale. Each page is of a different scale.

So I'm trying to reverse engineer these French drawing dimensions, based a few different sources:
       -- on published specifications like overall length, cannon barrel bore, ...
    -- my notes, photos, and measurements taken on my visits to cannons at the Orange County, CA [old] courthouse, the museum at U.S Military Academy, West Point, New York, and at Camp Roberts, San Miguel, CA.
  -- drawings from a U.S. Army _Handbook of Artillery _where, for example, page 84 shows a side view that has a scale of millimeters along the bottom. 

Here is the source of those French drawings:   Instruction militaire. Croquis du canon de 75 Mle 1897

On your project, the barrel I understand, but haven't seen anything called a "recouperator." I suspect that is part of the recoil mechanism. 
Are you needing the entire barrel assembly, or just the "barrel" itself, (the part with the rifling)? The drawings, in Plate 1, show the "canon" as a having several pieces, not counting the breech mechanism.

Maybe we can share information and each make some progress,
    Greg


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## peter orchard

Hi Greg yes I am making a barrel and breech ,recoil assembly where did you find the drawings with a mm scale ?

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## gjmontll

peter orchard said:


> Hi Greg yes I am making a barrel and breech ,recoil assembly where did you find the drawings with a mm scale ?
> 
> Sent from my SM-G960F using Tapatalk



Peter,

Here is a link to the _Handbook of Artillery_ 
M1897 in the U.S. Handbook of Artillery

And here's another U.S. Army Tech Manual, no scale or dimensions but much description and good drawings: 
TM 9-1305, Gun and Carriage, 75-mm, M1897, All types

I hope that link to the French document was useful. 
      Greg


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## peter orchard

Hi Greg I have not been able to open the French book how much of the gun did you draw up in cad ? The usa manual looks helpful with the scale 

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## gjmontll

peter orchard said:


> Hi Greg I have not been able to open the French book how much of the gun did you draw up in cad ? The usa manual looks helpful with the scale
> 
> Sent from my SM-G960F using Tapatalk



Peter,

Message me with your email address and I'll send you the French document as a .PDF.

The only pieces for which I've done drawings are just the few I've made: the axle (done as 3 pieces), the wheels (2-piece hubs, spokes, spoke shoes, felloes, joiner plates, and the steel tires).  I've spent well over a year trying to get adequate skills in the Fusion360 solid modeling CAD package. I think I will next tackle the carriage assembly, or maybe actually the barrel assembly.

So you have actual M1897 that's being reconstructed? Tell me more about your project. To what degree of authenticity must your machining conform? To what extent will it be operable? 

Greg


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