Thumb Wheels

The project continues apace with more turned parts. Again, these will need to be heat treated however at least I get to work with a fairly standard 5/16″ BSF (British Standard Fine) I cannot say I never work with imperial threads as all of the last weeks screwcutting was imperial and the time consuming part is always the clocking in as opposed to the screw cutting itself. Oddly, I do tend to work in metric for some imperial threads and as an example the 20×1/2″UNF thread so often seen on the end of barrels and used to attach a sound moderator starts off as a 12,70mm diameter to me and finishes at around 11,00mm for a class 3A thread (External) I say around as the ultimate diameter is down to the part I am attaching to the end so you could argue it is not really a class A thread.

I am sure some of you have shouted ‘Gotcha!’  confident now that you know what I am making. Good idea in principle however I think you will find this is the wrong thread.

All will be revealed over the next couple of weeks.

Screw it (The Imperial way!)

Firstly, Happy New Year, at this stage I could say my resolution is to write more however I have already failed on that count. Anyway, lets hope for a better year than the last. Here in the UK we are locked down for the third time which means no face to face customers unless they are essential users. Internet sales are OK though and we have already shipped to the USA and Sweden on multiple occasions plus theUK of course.

Screws- I am quite looking forward to this as it is an imperial job and I seldom if ever work in imperial. I need to make a batch of ‘Coned Head’ Screws and the drawing calls for them to be hardened so I will make a small handful and bung them through the HT oven, if all is OK I can make a few more, around 60 is where I need to be with some to spare/drop in the swarf bin/mess up along the way. The pitch is 38.48 TPI which would be a nightmare usually, however I can program this pitch on the big lathe and a 4,0mm collet seems to be my go-to for so many projects on both the lathes (Strikers and Optilock screws spring to mind) The thread angle is 47.5 degrees so not one I hold however carbide inserts are but a telephone call away. The slot will be done with a slitting blade held on an arbor with a collet on the manual lathe and I have a little 1MT Jacobs chuck that is held in a standard tool holder for holding the screws. The threads do not need to be timed so I can just wind the slide in with plenty of lubrication.

A sliding head lathe would be nice right now!

The project? You can probably guess what it is already and this is your first spoiler, however I will not admit to it until everything is finished and works as planned…

Some more Heat Treatment Oven time.

The little Heat Treatment Oven has been in use for a while and I have been thinking about the process cycle time for a while so yesterday we wound a new element with a calculated 2.5kWatts which should speed things up a bit.
First job was crunch some numbers and I use a spreadsheet for this, in fact I use spreadsheets for everything, even our RFD register! The advantage of the sheet is I can see what changes to the element length (Resistance) make to things like the current draw and power. I can also experiment with different gauges of the Kanthal A-1 wire I use which was handy as when I went to order the gauge used before, nobody stocked it in the length I needed.
A couple of entries on the sheet and I could instantly see if the alternative works and how much was needed. In the end I opted for 19AWG and ordered the wire.
The thing about the wire is it is just that, wire and not a heating coil so first job is clean it with acetone and wind it onto a mandrel on the small lathe. This is a bit of a two person job as having someone to hold and feed the wire to me saves potential kinks in the wire. Luckily the Viking was to hand as she usually is.
With the coil wound it was a simple matter of trimming it to final length and putting it in place, connecting in the terminal box and starting to test.
My target temperature for this test was 925-950 degrees centigrade (1700/1750F) This sort of temperature allows me to heat treat spring steels which I work with, a lot. Hence the target and I wanted to get to it in under half an hour so testing is important if only to prove my maths are about right.

Starting at 25C the oven hit 100C in 42 seconds, 500C/932F in just under 4 minutes and I stopped the test at 925C/1697F at a bit under half an hour which was perfect.

.The oven should be good for another 100-150C so I can have a play at knife making one day.

Right now I am watching the cool down temperature time.

The outside of the oven was cold to the touch at the 30 minute point however it is quite warm to the touch now at 90 minutes, however it is not hot which is excellent.
On the subject of spreadsheets, I created a plot of time vs temperature which I can use as a reference. The highlighted areas are the spring hardening and tempering temperatures I tend to work with, however these are material dependant.
Finally, I know, I really should get around to putting some decent labels on the control cabinet. Maybe next year
As a final note, if you fancy having a bash at making your on HT oven, I am happy to share whatever information may be of use to you.
Take care all.

Miroku 7000 crunchy triggers.

It is not all big stuff, first job the other day was strip and clean an old PH sight, the filter disk was filthy, warm soapy water and a soft tooth brush got the job done and I look forward to zeroing the rifle very shortly. Then, after a machining job and coffee it was time to jump on the gun work.
This particular Miroku 7000 had to be out for the following morning which is quite normal right now. It is game season and guns are seeing a lot of action, often after several months standing in a gun room or cabinet and without some tender love and attention they sometimes fail. then it is a matter of get them in, sorted and out again as quickly as possible.
The Miroku was a recent acquisition for an existing customer and he reported it having a ‘crunchy’ trigger. A service was about all that was needed which is quite lucky as spares seem to be slow to arrive right now.
Something to remember about this gun is it was probably built around 1990-92 (I have not checked the build year yet) and I doubt it has been opened many time since, in fact that looks like the original grease. not bad for a gun approaching 30 years old.
Stripping a Miroku is a very straight forward affair and the top lever spring removal is actually a remarkably nice single handed affair if needed, with no fear of things flying off. Fully stripping things is essential if you want to clean and inspect them properly.
The trigger blade should have a compression spring inside it which eventually came out with some persuasion. With everything cleaned it was re-assembled and tested and should now be good for many more thousands of shots. Interestingly I had a 6000 with a ‘Noisy’ trigger come in the following day so such issues are not unique.
A day in the life……
Take care all.

The Binbrook Gunsmiths.

A explanation of the Binbrook Gunsmiths is way overdue.
Already well established as the ‘Shooting Shed’ we moved to Binbrook in the Lincolnshire Wolds in 2015. Local customers always seemed to refer to us as the Binbrook Gunsmiths, so we have decided to split the gunsmithing and manufacturing to reflect the two sides of the business. This is going to make life so much easier for local people who require gunsmith services.
So, if your interest is gunsmithing services for Shotguns, Rifles, Pistols and Air guns or just about anything gun servicing, repairing or modifying related you need to make a note of our new website:
Facebook page:
If you interest is shiny stuff such as gauging, comparators, bore guides, bag riders and all the other things we design and make, the Shooting Shed side of things remains the same and we will continue to develop and produce our own range of products, known by shooters around the world.
Take care all.