Shop Made Tools

[pensioner]

It appears from the picture that the cannon is mounted at an angle to the lathe carriage, or at least the base plate is. Is this just an illusion?

I think the gun is aligned with the spindle axis. it cannot be otherwise.
I really like how the author solved the drilling problem in this case.

[davidwdyer]

That's certainly what I would have thought. That's why I asked the question.

[Arcane]

It appears from the picture that the cannon is mounted at an angle to the lathe carriage, or at least the base plate is. Is this just an illusion?

Do you really think someone who could come up with such an innovative method of boring that cannon would then just bore the cannon cockeyed?

[danlb]

David, I think it's an optic delusion. A cannon barrel of that style is often tapered. I think I recall they do it because the breach has higher pressure than the muzzle???

So if it is tapered, and shot at an angle, it can look like the bore is off center.

Dan

[Ironbearmarine]

Very cool engineering Ironbear, does the ram just push on the end of the drill shaft? I was wondering how you coupled it. Jim

In sharing this project with other people, i had to re-think some terminology. I didn’t so much make a long drill bit as more correctly, i have made a long throw quill that accepts drilling and boring tooling.
To feed the quill into the work, i used a properly aligned horizontal hydraulic ram. If i just engaged the ram to the back of the rotating quill, the ram shaft too would also rotate. Not desirable. My solution was to drill the back end of the quill to receive a single ballbearing and a pedestal. This would allow the quill to rotate freely while the ram shaft does not, even under heavy loads.

[Ironbearmarine]

In answering questions as to barrel alignment, that brings up how the barrel was mounted to the bed and how this was aligned. Essentially a cradle was fabricated that had a pair of plates on the underside to engage the bed just as the tailstock does. The main plate of the cradle was machined square and drilled and tapped to receive four bolts to act as leveling feet. Also were tapped holes for the hold down system. The barrel itself had been center drilled many years back, so with the barrel held between centers the leveling feet were engaged and the cradle tightened against these and relative alignment was achieved.

[Ironbearmarine]

“David, I think it's an optic delusion. A cannon barrel of that style is often tapered. I think I recall they do it because the breach has higher pressure than the muzzle?“

Slightly OT, but that was the belief in early cannon development, ergo the heavier breeches. During the American Civil War (1860’s) it was proved that the pressure was in fact equal along the bore. So for a time cannons became more straight than tapered in their profiles. With the change in metallurgy and manufacturing processes the built up breech soon returned as witnessed in the British Armstrong guns. And this would take us way out there in off topic land.

[rcaffin]

Well, all very well, but are you going to FIRE it? Only a small charge of black powder, and a block of wood, but ...
Where does one get black powder these days???

Cheers
Roger

[RMinMN]

Well, all very well, but are you going to FIRE it? Only a small charge of black powder, and a block of wood, but ...
Where does one get black powder these days???

Cheers
Roger

It has been a few years but I got my black powder from Walmart. There are a number of hunters in this area who like hunting with black powder so it is available from hunting stores.

[Ironbearmarine]

Well, all very well, but are you going to FIRE it? Only a small charge of black powder, and a block of wood, but ...
Where does one get black powder these days???

Cheers
Roger

Black powder, though readily available is classed as an explosive. Because of political paranoia, there are restrictions on how much you can possess and how it is stored. For some states you are only allowed to own a single pound. For us old cannon cockers, a pound of powder could equal 1 shot. So i use smokeless propellents and blackpowder substitutes which are not classed as explosives.
But when am i going to FIRE it?
Well, i had to insert a high pressure steel alloy sleeve down the bore so as to not rely on the cast iron to support explosive pressure. Also had to build a carriage. So a test fire is scheduled very soon

[mattthemuppet]

Ironbearmarine, I think I can comfortably speak for others when I say that you should post the build (and videos!) in a separate thread And that's meant entirely in a "you deserve more exposure" rather than a "it shouldn't be here" way

[Ironbearmarine]

Ironbearmarine, I think I can comfortably speak for others when I say that you should post the build (and videos!) in a separate thread And that's meant entirely in a "you deserve more exposure" rather than a "it shouldn't be here" way

noted. Slid a little OT, i know. And no offense taken.

[Bruno Mueller]

I have purchased a Bosch-Combi lathe from the German Armed Forces.
But some parts were missing.
Here I would like to present the refurbishment and the production of the missing parts.
First I show you the lathe as it should look like.



The lathe was already "the" dream during my apprenticeship.
After a long search and many failures I was able to buy this part at an internet auction platform for a bearable sum.
Year of manufacture of the machine: 1963
Until then, I knew from my active military service at the end of the 1970s that the Bosch Combi System was also in use in the German Federal Armed Forces. But I only found it in the stationary area of the company buildings.
I did not know that this system was also available to the fighting troops.
The system consists of components from the early days (band saw), the parts from the late 50ies, as well as the new components from the 60ies.
Band saw, belt grinder and scroll saw, as well as the small saw table and the jointer roller are still from the 50s. The headstock with the holes provided for it is absolutely necessary for use.
The last series of the headstock did not have these holes anymore.
The new equipment features, such as the large saw table with wobble saw device and the corresponding table holder are from the 60s.
In two suitcases everything for small metal and wood work is stored.

This is the machine I have refurbished. The cross slide was missing, a mount for the driving machine. A suitable drill chuck and the guide rail of the sliding fence to the sawing device.

[Bruno Mueller]

With Auto-CAD and Co. I am on a war footing. My drawings are created on a drawing board and are drawn with pencil.

For the assembly I made copies of the single part drawings, cut them out and put them together overlapping.

The drawings do not correspond to the DIN standard, but they will be sufficient for a reproduction.


First I intended to create the basic body as a welded construction. But I do not trust my welding skills. I have learned this once, but I lack the practice.

The sleds themselves I will make from steel S235JR+C (St 37).

For the basic body (cross slide carrier) I have planned a grey cast iron block made of EN-GJL-250 (GG25).

The original holder has only one central screw to fix it to the guide column. But since grey cast iron does not have the strength of white tempered iron cast, I added two clamping screws to this part. So the load for a single screw is not too high and the force is better distributed.



You can follow the complete documentation of the refurbishment on my homepage

http://www.bosch-combi.de/ersatzteile.html

[Bruno Mueller]

The top slide carrier was pre-milled.

First my band saw had cut a piece of the 70mm x 20mm material. Afterwards the part was machined on the milling machine.

The steps for the dovetail were pre-roughened. Thereby I left about 1mm material allowance. Afterwards the groove for the spindle was milled. The part was turned and the backside was removed with the flying cutter about 0.5 mm.

The part had to rest overnight, the inner tensions could be worked off and the next morning the part could be machined further.

The next day the top slide carrier was finished.