Fowler A7 traction engine fire door

28th August 2008. 1st session

I did start the work on the boiler fire door fittings a couple of days ago, but only for a
short time, having been unwell for a few days. So that short time has been included in
this update.

The fire door consists of a gun metal casting and attached to its boiler facing side has
a copper baffle plate, held off the door by three brass bushes. It also has another
fitting which is the door catch to ensure the door stays closed, or on another setting,
slighlty ajar. The final two parts are the hinge assembly and the brass block to which
the door catch fixes to.

After cleaning up the gunmetal door casting on both the front and back it was brought
to size (please see gallery below). The casting supplied by MJ Engineering (links
page) have the advantage of 4 dimples marking the four holes needed to be drilled
through (contd below gallery.........).

At first, only the three baffle plate fixing holes were drilled, to match the slightly larger than plan sized copper rivets (the
only copper rivets I had available with the correct length) used to secure the baffle plate.

The three brass bushes were turned to size and drilled through and put to one side. Next the small phosphur bronze small
pivot pin was turned and parted off. This pivot holds the latch which keeps the door closed and then it is riveted over on
the door later.

The next task was to make the copper baffle plate which sits on the three brass bushes and keeps the fire off the fire
door....(I hope...). To get a starting point I traced the outline shown on the plan ('borrowed' she who must be obeyed's
grease proof paper from the kitchen) and cut around the tracing, then fixing it to the copper sheet. I tried to cut it out on
the Proxxon bandsaw (worth its weight in gold!) and was very dissapointed with its cutting. I looked at the blade for
sharpness and compared it with my spare, and thought it wasn't to bad. However I decided to change it just to check
and the difference was enormous! I then had my efficient bandsaw back working fine and zipped around the outline.

Once the edges were draw filed, the copper baffle was held up against the fire hole in the boiler. Using my scribe I
managed to get a good scribe line around the baffle. This was then taken to the vice and filed to the line. Once done the
baffle was then returned to the boiler and high spots highlighted by permanent marker and frequent filing and checking
brought the baffle plate to size sufficient to enter the fire hole.

The rivetting of the baffle plate won't be done until the door is hung on the boiler and further filing of the baffle plate done
so it will swing into place. The door, plate, bushes and pivot pin were then placed in one of the storage containers
rescued from indoors....and a start made on the latch. When the latch is made it will be necessary to mill a 1/16th slot on
the rear of the door so the latch is flush with the back.

The latch is made from 1/16th thick brass plate and the size was scribed on to the plate with the digital height gauge and
the Proxxon bandsaw bought into use again to bring the latch blank to size. With final filing to the line using small diamond
files. And that is where the session ended.

Next time the latch will be completed and slot milled into the rear of the door. The hinge block and the brass squared
fixture screwed to the boiler for the latch to sit in...........watch this space....

time 2hours 30 minutes: total time 2 hours 30mins.

29th August 2008 2nd session

The first job tackled today was marking out the latch blank and drilling the hole for the phosphur bronze pivot pin. Then
the radius around the hole was shaped. To get the shape of the latch handle a 1/4" brass bar was secured in the vice
trapping the latch. Careful 'tapping' with a copper headed hammer soon had it to shape. Pleased, it was taken to the door
only to find it was the wrong way! Doh! So after straightening it was then tapped over the right way.

The next task was to mill out a recess in the fire door casting to allow the latch to be set flush with the back of the fire
door. My method was to use a rotary table to machine the recess. I decided that it didn't require my 6" rotary table and as
I have a small table as well, that was secured to the milling table. This is the first time I have used this little rotary table and
when looking for a method of securing the fire door, I realised I didn't have any nuts for the small 'T' slots!

So I had to machine some up and this took a little while. The rotary table was raised off the mill table by setting it on some
machine blocks (their first use as well). This raised the rotary table up clear of the handle and the fire door was then
secured with some aluminum to protect the front face of the door as it was only the raised letters that would be in contact
with the surface it sat on. Therefore very light cuts were made with the digital readouts used to maintain the accuracy of the
recess.

Once checked that the angle of clearance seemed to be correct, the fire door was removed and placed against the boiler
to make sure the latch would be able to be raised high enough to come out of the catch plate.

And that was enough for me today so the hinge plate and catch plate will be left to the next session (or sessions!).

time taken 3 hours 30 minutes: totla time 6 hours.

2nd September 2008 3rd session

Today the hinge was the focus of my attention. First, the blamk was milled to thickness then one edge was milled with a
1/4" round nose end mill for the 1/4" diameter drilled bar sat. It was then silver soldered to the plate and then picked before
cleaning up. I took the opportunity whilst silver soldering the hinge to also silver solder one of the bearing caps that include
an oil reservoir. So both items were then pickled and cleaned up. Please see additional photo's added to the galery above.

The next session will hopefully see the hinge fixture completed and the door hung onto the boiler. It has been surprising to
me the amount of work needed for the fire door.

time taken 45 minutes. total time 6hrs 45 mins

7th September 2008 4th session

After being a little unwell I managed to get an hour in the workshop so continued with the fire door fixtures, in particular the
hinge. The brass flat with the silver soldered 1/4" dia bar was placed in the vice on the milling machine and the central area
of the bar was milled away to suit the door casting. After cleaning up the door hole was drilled through after ensuring the
hinge part was at 90deg to the mill table.

The next task was to mill the hinge blank to size, leaving the rounded corners till the next session. I will turn some steel
'buttons' to the correct radius and use these to file the right radius on the hinge. The two locating holes were marked onto
the hinge and then centre punched with the littel tool seen in one of the photo's in the gallery.

It works by having a small perspex rod with cross hairs on the bottom. You place the rod over the mark and then carefully
remove the perspex bar and replace it with the steel centre punch. It works very well and was worth purchasing. I wouldn't
be without it.

time taken 60 minutes. total time 7hours 45 minutes.

10th September 2008 5th session

Well today I was determined to move on with the fire door. I had to take a little off the thickness of the hinge to get the right
angle for when the door was closed. The second part of the job today was to clean up the copper plate so the door would
close when screwed to the boiler.

I used the Proxxon (mini drill) with a small flap wheel to remove the surplus copper from the baffle. This took a little while as
I didn't want to remove more metal than necessary as the baffle is protection from the fire.

I didn't have any square bar of the correct size so had to mill some larger square brass stock to use for the latch post. Once
this was milled to the correct dimensions it was then taken to the Myford ML10 lathe and one end turned to size for cutting
a BA thread.

The boiler was taken to the floor standing drill and the matching BA hole was made in the blank stud soldered into the boiler
when it was made (commercially made). After tapping, the boiler was returned to the Fowler bench, and the square bar trial
fitted.

Next the latch was riveted to the door using the turned phosphor bronze pivot pin. To have something to hold the internal
head in place for riveting a bar was milled to fit between the pivot head and the copper baffle, then placed on the vice pad
and using a bar turned at one end, the head of the pivot pin was turned over, so securing the latch in place.

All this took most of the morning and felling a little worse for wear I decided to call it a day before breaking something!
All that is left now is to turn the two corners of the hinge and cut two slots in the square bar latch. One to hold the door
closed and the second to allow the door to be held ajar. The second slot will be cut as per the diagram on the plan.

time taken 4 hours 20 mins: total time

11th September 2008 last session!

Todays efforts saw the completion (until I see whats wrong compared to later work!) of the fire door assembly. Using the
Myford ML10 lathe, a filing button was turned to size and the two egdes of the hinge filed to shape. The next job was to cut
the slots in the square bar to the right of the door, upon which the latch will locate. To do this I first of all tried a hacksaw
however I thought that the Proxxon mini drill would be better. The cut was easily achieve but not to thickness. Then I thought
I would attach more cutting discs, to match the slot required. And surprisingly it worked! Something I will have to remember
in the future.

I have no doubt there will have to be some adjustments later, but for now that completes this phase of the build.

Time taken 30 minutes: total time 12 hours 35 minutes