1913? Galion horse drawn road grader

[gbritnell]

The frame is a little over 15 inches in length. I looked around for brass large enough to machine the rails from 1 piece but when I could find it the cost was extreme. At this point the build got put on a temporary hold.
One day while talking with a friend he asked how the grader was coming and I told him where I was, still looking for brass. He said that he had a chunk of brass in his back shed and it had been there for many years. If I could use it I was more than welcome to it. He dug it out and it was hard to tell it was brass. Time and the elements had turned it almost black.
I took it home and cleaned it up and it was more than I would need to complete the model. The only problem was the block was 12 inches long and I needed 15. I decided to make the frame in 2 pieces and silver solder them together.
As I was planning my attack on the frame another friend called and asked how the grader was coming along. I told him that I was laying out the material to make the frame. He has a shop full of CNC tooling and said that his machine guy was in between jobs and if I created a part model (Solidworks) he would have him cut it for me. I didn't hesitate at that offer so I created the models for the frame rails and took the brass and files down to his shop. Within the week he called and said the job was done and I could pick it up.
All of the pieces were machined leaving a .006 fin between the part and the parent metal. This simplified the machining for such an irregular shaped part.
I cut the parts free and started cleaning up the fins.
I made up a fixturing jig to hold the 2 pieces of frame together and silver soldered the joints. The next step was to make the end plates to connect the rails and give me starting point to add all the bits and pieces. A lot of the parts will be soft soldered together with rivet detail added at a later date.

[gbritnell]

There is no particular order to this build other than to make pieces that will allow other pieces to be made. I don't know how many pieces there will be but there will be a ton. The wheels were next. The hubs were turned and drilled for the angular spoke attachment. The rims were turned and also drilled for spokes. A fixutre plate was created to mount the rims and hubs so that the spokes could be inserted and soldered.

[MODEL A MODEL]

Beautiful start!

Thank you for posting! Could you show us what it will look like eventually?

[Roger Zimmermann]

Don: go to the beginning of this thread, you will see it.

Interesting machine! Doing the frame that way, it will have no irregularities!

[gbritnell]

Each of the spoke holes in the rim were slightly chamfered to allow the solder to flow around it. With the hub and rim mounted on the fixture plate the spokes were inserted and made sure that they were bottomed out in the hub. The exposed ends were fluxed and using small cutoffs of solder the spokes were soldered with a small butane torch.
The first pictures show the finished wheels and the second set shows the wheels standing in their approximate location to the frame.

[gbritnell]

This machine a large number of gears, worm, miter and spur type. There are 7 enclosed gear boxes with both worm and miter types then some of the exposed gears are spur pinions with curved sections of the same pitch.
When I reduced the scale I had the dimensions for the outside of the gear boxes and wanted to maintain the proportions so the gear sets had to be designed to fit within those sizes. This meant that, in most cases, non standard pitch gears would be needed. The same thing for the worm and wheel sets.
At the operators platform are 2 large gear housings in which are a worm sets. These are used to take the rotary motion of the large handwheels and rotate long shaft that raise and lower the blade assembly. I calculated the diameter and pitch of the worms and ground a high speed cutter to chase the threads on the lathe. For the worm wheels (gears) I had to make another cutter. This one was made from W-1 drill rod. The shape of the involute curve was drawn in CAD and replicated on the cutter. After the lathe work the cutter blank was put in the dividing head on the mill and the flutes were cut into it. Using a magnifier I carefully removed any burrs before hardening.
A gear blank was made and mounted in the dividing head to cut the teeth. From my drawings and calculation I determined the lead angle and tilted the head to that angle. There is one right hand set and one left so the head had to be tilted to both angles.

[gbritnell]

When trying to replicate complex shaped parts, especially castings, in most cases it's necessary to create the part from several to many components.
This is the case with the gear housings for the worm sets previously shown. The box is basically a circular shaped part with a rounded section at the bottom which houses the worm.
Starting with a block of brass cut to the overall dimensions all the holes were put in. This is the first step in making any parts because you have square and flat sides to chuck to. If you cut the profiles first in most cases there's no way to hang onto the part for drilling or boring operations.
The worm hole was put in then the block was flipped 90 degrees and the gear cavity was roughed and finish bored. The mounting holes for the outer cover were also drilled and tapped for 0-80 screws.
With all the holes put in the block was slowly whittled away to create the shape.

[gbritnell]

When I learned my trade many years ago (metal patternmaker) We were taught to cut curved shapes using a ball end mill. This was the days long before CNC.
Each machinist had a small 'black book' with step-off charts for various radii using different radius cutters. These were valuable books considering that all the calculations (sine and cosine) were done by hand. No calculators either! Sometimes a rotary table can be used but in a lot of cases the fixture and setup time doesn't justify the tooling changes.
As I mentioned the housing has a radiused boss at the bottom which houses the the worm gear. With the major shapes roughed in the boss was stepped off.
The part was removed from the mill and the small steps were filed and polished to give the part a finished look.
The part was then put back in the mill to do the other side of the gear box. This side has a protruding boss with 3 stiffening ribs. It would have been extremely time consuming to try and do this as one setup so the ribs were cut then the housing block was tilted to cut the angle on the ribs. A small tube was machined and inserted between the ribs and soldered in place.

[Roger Zimmermann]

Well, it seems that you know what you are doing! Nice parts, by the way, and nice machines!

[gbritnell]

It was now time to machine the radius on the outside of the gear box. There was no easy way to hold it because the radius needed to go the fill depth of the box so another fixture was needed.
A piece of aluminum was drilled and tapped to hold a boss that would fit inside the cavity on the other side of the box. This was mounted to the plate with a small screw through the center hole but this wouldn't provide enough holding power even with light cuts so I made another small block with a circular cutout.
This would hold the boss at the bottom of the gear box and keep it from rotating.
The rotary table was put on the mill and the center picked up by indicating the boss. The gear box was then mounted and screwed tight.
A first cut was made down to the backside of the bolt bosses which hold the front cover in place. The second cut was down to the full depth. I had to be very careful when coming around to the features on the gear box so that no 'oops' cuts were made.

[gbritnell]

Thanks Roger,
Coming from you it's much appreciated. I've been doing this for 50 some odd years so I had better have learned a thing or two.
I can really appreciate the work you do with your machines. In my early days it was just a lathe with a milling attachment.

[MODEL A MODEL]

Oops, sorry. I’m stilling using my phone and don’t get the whole thread.

[gbritnell]

The gear boxes needed end caps for the worm cavity. Each end was a different shape. One end was fairly simple but the other end needed a lot of fine work with my Dremel and riffler files. The end caps were slid onto a rod and inserted into the gear box and soldered in place. At that point a little more hand work was needed. The cover plates were turned and milled as you see. There is a triangular boss on the front of the cover which on the full sized machine is for an oiling hole for the gears. I created the boss but don't know if I will drill it or not.
gbritnell

[gbritnell]

The finished model won't have socket head screws but rather all square headed bolts and nuts which were common for the era.