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Member postings for Mark Elen 1

Here is a list of all the postings Mark Elen 1 has made in our forums. Click on a thread name to jump to the thread.

Thread: Grand Piano Bolts - 6.6mm x 22tpi
08/12/2019 20:04:10

Hi Mart,

Yes, the restorer is going to give me a call when it is done to go and have a look. I finished off the radius tool last weekend, then finished off the bolts. The original is the one on the left. My new ones are the 3 on the right.







17/11/2019 16:54:29

Many thanks for your kind comments gents.

Yes, Robert, after a bit of research, BSF was adopted by BESA in 1908. Whitworth was earlier.

The Hamann Patronen was a German Machine thread from 1850. Used on Mechanical and optical instruments



Edited By Mark Elen 1 on 17/11/2019 16:58:04

Edited By Mark Elen 1 on 17/11/2019 17:02:30

17/11/2019 15:08:51

I forgot to say that I got all excited when I found that 5/16 BSF is 22 tpi, and that I could get a die. Apparently the Germans used a lot of British Standard threads in those days. I thought great, just buy a die and cut the threads with that.

Only snag is, 5/16 BSF major diameter is 7.9375 mm



17/11/2019 14:58:11

I was in the local nut and bolt merchant last week to overhear the proprietor telling a local piano restorer that he had never seen anything like the bolts the restorer had presented to him.


They basically hold a wooden frame into the top of the open part of the piano.

As I walked in, the owner of the nut and bolt shop was saying that the local engineering shop would be the best first port of call, but that they were flat out busy. What he needed was somebody with a lathe in the garage.... (the words were.... just the man.)

I agreed that if I could work out what thread was on the bolt, and also set my lathe up to cut it, I would oblige.

Measuring the bolt, over both the shank and the threads, it is 6.6 mm, with a set of thread gauges, it is 22 tpi. The only thing that I can find anywhere near that is an old German thread, from the 1850s, a Hamann Partonen 7mm x 22 tpi.

As the parts come from a 140 year old German Grand piano, it looks like a promising candidate.

My lathe (a Seig SC4) doesn't have a 22 tpi gear setting -


But looking at the above, as the 20 and 24 settings basically use the same first 3 gears and it is only the last gear that produces the 20 and 24, I used the logic that a 55 would be smack in the middle.

I roughed out the shanks to 6.6 mm and set to work screwcutting the thread. Amazingly, it fits:





3 made, I need to round off the heads and cut a slot, so I have ordered a Hemingway radius tool that I'm going to have to make. Once done, they can go in the mill and have the slots cut with a slitting saw.

An interesting little project.



Thread: Hemingway Hacksaw
09/11/2019 13:14:41

I have got on and remade the vice slide block. I had to set up the vice riser again in the mill to drill for the screw hole:


And here is the block I made that is a good tight fit in the slide, so that I could use an edge finder and the DRO to find centre:


I then clamped up the vice jaw with a couple of small .8mm aluminium shims to hold the jaw and block in place while I drilled out to 11.1mm. You can just see them poking out of each side of the jaw:


I then set it up in the 4 jaw and spent a long time getting the hole central on the lathe, followed by a lengthy set up of the change gears. The SC4 that I have would be OK for 16tpi right hand, but for left hand, the 120 gear hits the spacer in the gearbox when the 30 gear is swapped to reverse the lead screw. I ended up taking the spacer off, along with the woodruff key and holding the gear in place with a small washer that slid between the 120 and 127 gears. Not great, but usable.

After all that, the 6mm single point tool just sprang away from the hole and didn't touch it... Grr.

I ended up setting it up in the vice and tapping it by hand. It went better than last time, but not much.

Once that was done, it went back in the mill and I brought it down to finished size.


All in and done. The vice is a little tight, though not overly, I'm hoping it will bed in and slacken off a little with use:




Thread: Yet another 'which mill shall I buy'
08/11/2019 18:04:52

I have an SX3 that I bought from ARC a couple of years ago. I’m really just a beginner, but I’m happy with it.

I bought a DRO with it, along with glass scales, all from ARC. I shamelessly copied the bracket setup that is in the showroom at Leicester. It was the first job that I did with the mill.

I still haven’t got around to making the brackets for the z axis scale. If you want some photos, let me know.

If I was doing it now, I would be looking at the smaller magnetic scales, just for neatness.


Thread: Hemingway Hacksaw
07/11/2019 19:30:25


Taper Tap. I had a similar thought re roughing it out on the lathe, in fact I have bought a 55 degree 6mm internal hss tool. The problem is, the slide needs most of the machining doing, so that it can be held in place in the vice to get the hole in exactly the right place.

The other problem is that as the hole is only 11.1mm minor diameter, it needs a tiny internal threading tool. The part is 3/4 thick, so the tool is stuck out a long way in the tool holder. (Also, there is going to be a lot of very close up work to the Chuck. At least it is left hand, so all of the cutting will be going away and not towards the Chuck)



Sorry, I have just clicked what you were saying re the tapping before machining. 
I will have a go at roughing it out on the lathe, once I get it machined down and the hole drilled. I can see a lot of hand winding of the tool back in coming.... I really need to get my hand winder that I have planned for the back of the lathe spindle made. 

Edited By Mark Elen 1 on 07/11/2019 19:55:22

07/11/2019 18:58:56

I have tried....and failed to tap the vice slide. I bought a 1/2” BSF Left Hand HSS tap. I drilled out the cast iron to 11.1mm then had a real struggle to get the tap to start.

When it did, it felt like the tap was going to snap, so when it went ‘click’ I was fully expecting a tap in 2 bits. What I got was this:


Needless to say... there were a few swear words issued. There was a few hours work in that piece.

I’m now busy making a new one out of a piece of 50mm square cast that I bought this week. I’m wondering if I need to drill it out to 11.3 or 11.5 before I have another go, although, this time there will be plenty of meat around the hole, I will mill it back once the hole is tapped.

Pointers would be appreciated



05/11/2019 18:57:20

Hi Simon,

Thanks for the info on the slide bar. Mine is too tight. I ended up making some shims out of 4 layers of tin foil to allow it to slide. It is still fairly tight though. I may need to revisit this before it is finished.



05/11/2019 18:52:36

Hi Folks,

Many thanks for your comments. I have had a bit of time off this build. Lost interest a bit, but recently got the urge back to continue.

I have got quite a bit done but had the odd issue. The first thing I did was to sort out the riser for the vice. I had drilled and bored out for the vice screw as one of the first jobs I started with. Needless to say, they were miles out. I ended up making an aluminium block that was a good tight fit in the slide way of the riser that I could use to pick up the edges with an edge finder.

Before doing that, I set the riser up in the vice and ran a DTI down the slide way. Once I had picked up the centre, I bored the handle end until I had taken out the error, it ended up ~14mm

The other end wasn’t as bad, I managed to set it up the same and a 10mm endmill sorted it out.

I had to adjust the vice screw to my new dimensions. As I want the vice to operate the ‘right’ way, I got set up and screwcut a 1/2” BSF Left Hand thread, finishing it off with a die.


Next job was to set up and bore out the bottom brackets to 5/8”:


Then I got set up to make the drive shaft. This calls for a piece of 1/2” bar to be turned down to 11mm. I ummed and aaared as to how to set this up, but ended up with a small chunk in the 3 jaw and a live centre at the other. The first skim cut showed the tailstock being out of alignment. I had nearly .4mm difference over 5”. There followed a round of adjust, skim, mic, repeat until I got it down to .04mm

Done, in the mill and slot cut for key, key made and in, finished:





It ended up at 10.996mm one end and 10.992 the other. The hole in the gearbox is a touch under 11mm, as a piece of 11mm ground rod will not fit. (I bought it to save making this.....)



11/02/2019 22:23:43

I got the hole drilled in the boss, then set back up on the table using the slide bar and clamps to hold the bow in correct alignment. I took really light cuts, because the bow is just hanging in free space.

I milled off the ends and the waste in the middle, made up the threaded adjuster, I need to mill half of the end off now and drill for the pin. I have marked up for the M5 screws to hold the blade, just need to drill and tap.




I have had to go 'off piste' with the adjuster screw, putting a 120 degree cone on the end. The drawings/casting is a bit out. the boss should be 1" long, but just skimming the end square, left it 3/4". I drilled down 39mm, the drawings called for 1 3/8" (34.93mm) even with this adjustment, if I had left the adjuster square and drilled for the pin at 1/4" the blade would not have fitted.

At 1/4" from the tip of the cone, the blade should fit with a little slack.



10/02/2019 17:08:57

One of the things that I have not been looking forward to was machining the bow. I don’t know why now. I got stuck into it last night, doing the slides first, then today I have set it up on the angle plate and drilled the boss.





Don’t look too closely at the spirit level on the square... I still need to level the mill.



08/02/2019 10:28:18

Hi David,

Many thanks for your kind comments.

I have got a bit more done in the last few days. The con rod is complete, I reamed out the 1/2" hole and bored out the 5/8"



Then I decided to start work on the slide bar retainers. These took a bit of working out how to hold them as the castings were not square. I had to square up one side and make up a set of soft jaws to hold these whilst I worked on them.

The bosses for the screws didn't line up too well either. I decided to use the dro, line up centre on the raised portion on the back of the casting, then place the holes as best I could in the bosses.

The holes are correctly placed at 2" centres (50.8mm) but they don't line up in the bosses very well.







03/02/2019 15:23:56

A bit more done today. I got the crank pin milled down to 1/2” square, then milled out the 1/2” slot in the crank wheel using a 8mm Ali slot drill. I finished off the corners very carefully using a needle file.






02/02/2019 16:40:48

I got to the limit of the boring head, as the head itself was going to hit the step on the soft jaws, so I changed over to the rotary table and end milled off the rest.


I also got started on one of the crank pins


And set it up in a square collet block to mill it down to 1/2” square for the crank wheel:




01/02/2019 10:12:42

I decided to make up a set of soft jaws to hold the crank wheel.....

I have cut up a piece of 1" aluminium to fit the vice jaws and a couple of shorter pieces to hold the 'proper soft jaws' in the correct position.

I also took my own advice, that I gave Ron a few weeks ago, and bought a SCLCL 12mm Left hand boring bar to fit the boring head.

I used a right hand bar, cut down to fit the boring head to take out as much as I could, then swapped to my new left hand bar. First thing I had to do with the bar, was cut it down to fit.


I have still got a way to go, the sides of the cut are great, but the bottom has a few ridge marks. I'm sure for this it wont matter much, but I am trying to think of ways to clean these up.

Thinking about it, these would probably been better set up on the Rotary Table and end milled out.



Thread: Beginners Engine Advice?
28/01/2019 23:53:05

I have made my decision regarding this. I have decided to have a go at building LBSC's Pansy.

A few of things conspired to making this decision:

1) Doug Hewson is running a 'Update' series in Model Engineer (and I have just taken out a subscription)

2) It was what I first wanted to build, but I didn't fancy the bending and fitting work of the pannier tanks... I still don't, but if you don't push yourself, you don't move forward, I'm just going to have to go for it.

3) The GWR 5700 series was the first engine I had as a kid, and I can still remember the Hornby 'steam' experience with the fluid down the chimney.

4) I must be mad.

There are loads of things I'm not really looking forward to, the crank axle and the horrendously expensive cylinder casting being just 2. But there are loads that I am. I can see this being a long term build, but I'm in no rush.

One of the first things I need to do is to join a local engineering club, I have a couple to choose from locally, I will get around to both and have a look around.

I bought 3 full volumes of Model Engineer (118,119 and 120) covering LBSC's full words and music of the build and over the last couple of days have scanned every page and PDF'd and collated the lot into one large file. The build was covered every other ME, but LBSC wrote every issue back then, there are loads of interesting articles in the intervening issues.

I have seen during my research that there are some issues with the plans, I'm hoping these will present themselves during Doug's Updates - any pointers from the combined wisdom here would be much appreciated.



Thread: Hemingway Hacksaw
28/01/2019 17:42:27

I got the collet finished, then bored the crank wheel to 10 degree included. Mounted the wheel on a piece of 11mm silver steel using the collet.

The casting comes with loads of 'meat' to remove to get to final dimension. Here it is when I first started on it:


and here it is coming into dimension:



I have got it marked up and ready to mill out the slot for the adjustable stroke, but have been mulling over ways of holding it for milling. I'm leaning towards making up some soft jaws out of ali to hold it in the milling vice. - it would probably be quicker to just bolt it down to the table....



22/01/2019 21:14:42

Tonight, I got the collet set up in a hex Stevenson’s block and sawed out the cuts. I got 90% done with the saw, the last bit I took out with a needle file.




21/01/2019 21:55:43

Ok, back on with the hacksaw build.

I made up a 5/8”BSF nut and the collet. I still need to slit the collet.





Edited By Mark Elen 1 on 21/01/2019 21:58:39

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