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BaronJ
12th Sep 2018, 03:08 PM
Hi Guys,

I thought I would do a WIP for a project that I thought about quite a long time ago but it got put aside because something more urgent came up. Some of you will know of a simple quick change tool holder for the lathe called the "Norman Toolpost" !

Some time around 1890, an improve lathe tool holder was patented, this became known as the "Norman Patent Toolholder". This design was adopted and used by many makers of lathe, including "Drummond". It was also used by "Rolls Royce" on various lathes in their experimental workshops.

It is an easily adjustable and versatile device that can be adapted to suit most lathes, particularly smaller ones. I have redrawn the plans to make this tool holder and of course sized it to suit the Myford lathe.

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I propose to describe the steps that I took in order to make this tool holder. Whilst not an accurate copy of the original 1890 patent, it is my interpretation of it.

The design consists of three basic parts. The tool holder block itself, the support post and the pinch clamp. I'll post a drawing of the support post later. The tool holder block is a 65 mm long piece of 50 mm by 25 mm of bright mild steel bar. I cleaned up the ends and brought it to length in the mill. After de-burring, I painted the top and one long edge with a permanent marker prior to marking out.

To be continued:

BaronJ
13th Sep 2018, 03:56 AM
Hi Guys,

I've done some more work on making the Norman Toolpost.

As I mentioned in the previous post, I had painted the top and one edge, prior to marking out.

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I used a green permanent marker, but as you can see it ran out so the other edge is in red. I think the green is better to see the scribe lines.

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Some of you may remember the digital hight and marking out gauge that I made some time ago. This is the device that I used to scribe the lines on the block.

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The first line was down one edge. I set the gauge to 6 mm and then scribed a line down the block for the centres of the three tool holding screws. I then marked each end screw position and last the one in the middle.

Setting the gauge to 12 mm, I marked the back of the slot where the tool bit will sit.

Next I needed to find the centre on the edge for the split clamp hole. Setting the gauge for 12.5 mm, I scribed a line, then turned the block over and scribed it again. Surprise the two lines were one on top of the other ! I had expected to have to split the difference.
I'm quite pleased at that.

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After marking the centre line for the split clamp hole, a few minutes with a centre punch and I was ready to drill some holes.
I first drilled the three holes 5 mm, the tapping size for M6. I didn't drill right through, I only went down 10 mm. Since this area has to be milled out to 12 mm by 12 mm, the milling will clean up the bottom of the holes. Saving having to deburr the underside later.
I followed the drilling by countersinking the holes slightly. This should stop any burring at the top when threading.


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At this point I moved over to the lathe and swapped chucks for the independent four jaw. I spent some time getting the tool block
accurately aligned. Unfortunately I didn't take any pictures of this. Its quite fiddly and requires concentration.
Note to self: there has to be something easier than squinting at a dial gauge and not going the wrong way.

Now whilst I remember ! That jaw stuck out is a hazard ! I really ought to have removed it, but I didn't ! Though I did take care to keep my hands and any clothes well away from it whilst drilling.

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But no mishaps. My missus would have been very upset if I had got hurt, and then she would have gone to town, telling me off. :o

Right I'm going to stop here, because I want to move on to boring the hole for the post.

To be continued:

jack620
13th Sep 2018, 06:52 PM
Hi John,
I'm not sure what method you used for centring the punch mark in the 4-jaw, but a very easy method is to use a wobbler and a dial indicator. I used this method to centre the crankshaft bore for my model diesel engine. Here's a pic. Hopefully self-explanatory.

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You already have a spring centre, so all you need is to make the wobbler. It just needs a sharp point and a centre hole in the back end for the spring centre to rest in.

That protruding jaw sure caught my eye!

BaronJ
13th Sep 2018, 07:51 PM
Hi Chris,

Thank you for your picture ! Now I have seen what you use, I can see why I struggled.

I was trying to use a dial gauge supported by a stand on the topslide, with the gauge on top of the work.
So I will make a gauge holder like yours and a wobbler !

I was going to bore out the post hole using the mill, but I will make the bits that I need and try again.

Pictures to follow...

Thanks:

BaronJ
14th Sep 2018, 03:17 AM
Hi Chris, Guys,

Thanks to Chris for the enlightenment. I've spent most of today making a dial gauge holder to support my Mercer using the toolpost.
I've also made a wobbler.

I promised pictures so here goes !

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This is the piece of aluminium that I cut from the end of a length of 120 mm by 80 mm bar. By hand with a hacksaw. It was just too big a lump to use the bandsaw. However after facing it flat on the mill, both sides, I then cut it in half. This gave me this bar 120 mm long 20 mm wide by 12.5 mm thick. I don't fancy cutting that big chunk of alloy again too soon.

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After cleaning the sides up and a little bit of marking out and drilling two holes, one 8 mm diameter for the dial gauge stem and a 3.2 mm tapping size for M4. Gave me this.

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After threading the hole I then cut a slit from the end right through to about 6 mm past the hole for the gauge stem. I drilled out one side of the threaded hole to clear the M4 cap screw. This alloy is quite soft and whilst it traps the gauge stem just fine it gives a lot. Steel wouldn't have given as much. I didn't measure the dial gauge stem length till I got to this point, the bar is 20 mm wide, but the gauge stem is only 15 mm long, so it looks slightly odd in this picture. But that hole is dead square to both sides. I checked :D

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And the final result. Its a perfect fit into the slot on my lathe tool holder.

Thanks again Chris.

Steamwhisperer
14th Sep 2018, 09:20 AM
Hi Baron
for getting a centre punch running true in the lathe I use a different kind of wobbler. The beauty is that I don't need a dial indicator. :)

Phil
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jack620
14th Sep 2018, 10:04 AM
John,
You'll also find that indicator holder very handy for centring square stock in the 4-jaw when you don't have a punch mark to work with.

Phil,
I haven't see one like that before. I assume you adjust the jaws until the point on far end of the wobbler and the point on centre in the tailstock are aligned by eye? Is it accurate?

BaronJ
14th Sep 2018, 10:47 PM
Ooo Phil, I like that one. Very simple, elegant even. A mechanical amplifier. :2tsup::2tsup::2tsup:

What did you use for the pivot ?

Steamwhisperer
15th Sep 2018, 07:31 AM
John,
You'll also find that indicator holder very handy for centring square stock in the 4-jaw when you don't have a punch mark to work with.

Phil,
I haven't see one like that before. I assume you adjust the jaws until the point on far end of the wobbler and the point on centre in the tailstock are aligned by eye? Is it accurate?
Hi Jack
You have it spot on. The point on the end doesn't have to be in alignment, I just line it up there for a reference. So long as the end isn't moving or at the least moves very little then it is accurate.
As far as accuracy goes, the distance from the work piece to the pivot and from the pivot to the end (near the tailstock centre) is the key. For arguments sake lets say the distance from the chuck to the pivot is 50 mm and the distance from the pivot to the tailstock end is 500mm then the movement of the centre punch mark will be 1/5 of the movement of the end near the tail stock. It is actually quite easy to get next to no movement at the tailstock end so even less movement will be at the centre punch. A prick pinch can work for extreme accuracy.

Ooo Phil, I like that one. Very simple, elegant even. A mechanical amplifier. :2tsup::2tsup::2tsup:

What did you use for the pivot ?
Hi John the pivot is just a small tie rod end. It then gives free movement in all directions.

Phil

BaronJ
15th Sep 2018, 08:27 PM
Hi Guys,

Phil: I'll make one of those later when I've finished the Norman toolpost thread. Mm 500/50=10 :q

Chris: It works a treat, I don't know why I pratted about so long before.

Its nice to learn something new.

Thanks Guys.

BaronJ
15th Sep 2018, 10:19 PM
Hi Guys,

There are two things that need to be done before setting up to bore the large hole in the tool block.
Making this pin and drilling and threading it.

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This is a drawing of the pin that is used to make the split clamp. Whilst I have shown the hole as 1/2" inch (12 mm) on the drawing, I didn't have any silver steel of this diameter, so I used 14 mm diameter, of which I have a full length of.

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I cut a length of silver steel bar to fit into the 14 mm diameter hole that I had drilled through the width of the tool block.
I then faced off the ends.

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The next step was centre drilling and then drilling all the way through with a 5 mm drill, the tapping size for M6.

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After drilling I threaded both ends the full length of the tap. Later It is going to get cut in half anyway. And one half is going to be drilled to clear M6.

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This is after checking and cleaning the swarf out. I used the threaded rod to clean the threads, since all the tapping swarf gets trapped in there.

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The pin was a little over length, in this case 17 thou. So I took an 19 thou cut off one end. (No that isn't a typo) There is a good reason for doing this. That pin is going to get machined when I bore the large hole for the mounting post. The pin is a loose sliding fit in the hole. It will drop through smoothly without being sloppy.

At this point I seem to have lost the pictures of setting the tool holder block up in the four jaw. Sorry about that ! :o
All the excitement of using my new dial gauge holder and wobbler pin.

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Here you can see how I secured the pin into the tool block to secure it for boring. The pin will get a hollow machined into it exactly the same diameter as the hole. That nut you see is just on short bit of threaded bar, it does not go all the way through. There is a large washer on each side. The idea is to clamp the pin securely in place. Now you can see why I machined a couple of thou more than needed from the end of the pin.

That boring bar is over a hundred years old ! It was given to me by an old mentor. Apart from being touched up now and again it leaves a great finish, and is very rigid.

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Another picture whilst cutting. I don't care for taking pictures this close to running machinery.

More Later:
Thanks Guys.

BaronJ
16th Sep 2018, 01:03 PM
Hi Guys,

Its just turned 2:15 am here. I'm struggling with getting to sleep, so I thought that I would chronicle yesterdays progress on my Norman Toolpost.

As you know I got the large post hole bored out and after removing it from the four jaw chuck, spent a little time removing the rather nasty harrage from the back of the hole. I also removed the pin that I had secured in the block with screws and washers.

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Here I am taking a final check on the bore size with a pair of inside spring callipers. I'm aiming for 35 mm diameter. It doesn't really matter if I'm a bit out because I haven't made the post yet. But it is nice to see how accurate I am, particularly with an imperial lathe and metric sizes.

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Well here is the result. Give or take a tenth, that will do !



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The surface finish looks to be very good. The pictures make it look worse than it really is. The boring was done at about 200 rpm with a
1 mm depth of cut and feed of 16 thou. The final cut was done with a depth of cut of 10 thou and a feed of 2 thou. What I did notice was the sound of cutting change as the cut went over the pin material. Obviously a much harder metal.

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This is what it looked like when I removed the pin. It was a bit harder to remove than it was to put it in place. Those edges are like razor blades. No way do you want to be rubbing your fingers in there. Still the pin is a nice sliding fit.

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This is the pin as it looks when I removed it. The two screws and washers are stopping it rolling away.
The surface finish in the scallop is really smooth, almost as if it had been ground. I wish I had realised how different it looked and taken a picture before I removed it.

The next job is to deburr and split it.

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I swapped chucks putting the three jaw on and parted the pin in the middle of the scallop. Whilst I had it in the chuck I de-burred the end and drilled it 6 mm clear, removing the threads from this end. I swapped the pieces and de-burred that.

That's all for now.

Thanks Guys:

BaronJ
17th Sep 2018, 04:13 AM
Hi Guys,

Moving on !

I've now machined the slot for holding the tool bits.

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I set the tool block up in the mill vise. I did check that it was square, though it doesn't look it in the picture. The 12 mm diameter slot drill is a Sutton Tools one. After finishing the slot to depth 1/2" inch, I took another cut of 1 mm off the bottom edge to give me a 13 mm wide slot.

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Here I'm cutting down to depth in a series of 4 mm deep passes at 600 rpm. This is about as deep as I can go without causing both the spindle and the table drive to bog down. It takes just under a minute to do a pass. That creamy off white stuff is the cutting oil that I'm using.


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Here is the result. I'm quite happy with this so far.

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I have now tapped the three holes for the clamp screws and de-burred the inside of the slot where the threading had raised burrs.
I also went round and broke all the sharp edges. I used a countersink to take the edge off the holes.


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One of the last jobs to do on this tool block, was to drill and recess a hole for the hight adjusting screw.
After using mark one eyeball, because I forgot to mark it out and centre punch where it needed to go.
I drilled a 5 mm hole, M6 tapping size, all the way through. Then using an 11 mm drill, because I don't have a 10.5 mm one, I drilled a recess to a depth of 10 mm, to accommodate the head of the M6 cap screw that I'm going to use for hight adjustment.
M6 is a nice size to use for this kind of adjustment because the thread gives you a nice 1 mm per turn.

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I also trial fitted the split clamp, to make sure that it didn't bind when I fit the screw in there. I also checked the gap, which works out at exactly 2 mm.

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You will also notice that I have rounded the split clamp end of the tool block. Not for any particular reason other than it looks good.

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And here is the tool that I did it with.
It is an ordinary woodwork carbide router cutter intended for rounding the edge of wood. I used neat cutting oil and experimented with cutter speed. I found that the cutter seemed happiest at about 1100 rpm and 0.25 - 0.3 mm depth of cut. What really surprised me was how the surface finish improved as I pushed the speed up from 600 to 1100 rpm. No colour change of the fine chips that were produced, so I could probably pushed the cutter harder. Though the fact that the cutter is only on a 1/4" inch shank, made me a little cautious.


So that is it for the tool block ! Next up is making the mounting post to fit in place of the existing one.

Thanks Guys.

BaronJ
18th Sep 2018, 07:52 AM
Hi Guys,

This part is the easy one, making the post ! Warning this part is picture heavy :)

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This is the drawing for the post that the tool holder block is secured to in use. I've not shown a dimension for the central hole, since it will depend upon the size of the tool post bolt on your lathe. However for the Myford 7 series of lathe it is 7/16" inches or 11.11 mm.
This is the size that I will use since it is correct for my lathe.


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I had this 50 mm long off cut of 40 mm diameter bright bar. I think I picked it up out of the scrap box at one of the engineering places I visit from time to time. So what the material actually is, is not known.

One of the problems with using this piece of material, is that it is barely long enough, I only have about 10 mm that I can grip with the three jaw chuck. So what I did was to chuck the whole length, then face off the end, marking where jaw No:1 was, removed it and turned it round, then faced off the other end. After facing it, I then centre drilled it.

Swapping the drill chuck for a live centre, I packed behind the bar with a packing piece and used the live centre in the tailstock to press the bar against the packing and support the free end.

Unfortunately I didn't take any pictures of turning the piece of bar to size.
However I was running at about 700 rpm and using 1 mm depth of cut with a 8 thou feed, except for the last cut which was 0.25 mm and 2 thou feed.

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This picture will give you an Idea of how I supported the bar whilst I turned it down to 35 mm diameter. Though I am actually parting off.

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Here I'm just doing the final drilling of the 7/16" diameter hole, and a picture of the turned to size and drilled workpiece.

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Yes this is the same picture from above, where I am parting the waste bit off the end.

The second picture shows the parted off end. Notice the score mark at the bottom. That was caused by a piece of swarf getting trapped between the blade and the workpiece, and having nowhere to go, so it embedded itself in the side of the softer material. It also stalled the chuck. Fortunately just belt slip and no damage.

I've got the belt tension quite low. I really should replace the belt, its black, horrible and oily.

The parting was done at the same rpm as the turning and fed by hand. The cuttings were coming off as quite long strings with intermittent small chips. This material is definitely not as free cutting as it appeared to be whilst turning.

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After I had parted the waste off, I then put a 45 degree chamfer on each end and de burred the hole by countersinking.

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This is the finished tool holder mounting post.

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Trust me to have an 11 mm drill in the box at the 7/16" position :doh:
Luckily I have a spare box of drills and a new 7/16" one in there.
The part below the threads is a smidgeon larger than the thread.

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After running the new drill through, it fits perfectly.
As an aside the diameter of the post was chosen so that the tool block would fit over the ratchet at the bottom without having to remove it from the topslide.

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And it all fits together perfectly. In use there should be about 5 or 6 mm gap under the tool block.
All that is needed now is to finish the split clamp and fit it.

But I'm going to leave that for the last part !

Thanks Guys.

caskwarrior
18th Sep 2018, 11:16 AM
Nice work Baron, I really like the grind and size of that chamfer tool! Are you going to be using or removing the ratchet mechanism?

BaronJ
18th Sep 2018, 09:22 PM
Nice work Baron, I really like the grind and size of that chamfer tool! Are you going to be using or removing the ratchet mechanism?


Hi Caskwarrior, thanks for the kind words.

That tool I used, It is just a cheap carbide wood router bit ! I've done nothing to it other than put it into a 1/4" collet in the mill chuck.

My only reservation is that it is a small shank diameter, I would have preferred to have used a 1/2" shank one ! But I don't have one, and unless I'm going to make regular use of it, I wont buy one. Particularly since they want more than four times as much for the thicker shank ones. I think the box of ten that, that one came in cost me £9.95p out of Lidl. Though I notice that they have now put the price up to £12.99p.

I originally was going to leave the ratchet on, and cut a recess into the bottom of the tool block, then realised that because the tool block was going to be lifted by the screw it wouldn't work properly, if at all. Also the rigidity relies upon the tool post being clamped firmly to the top slide surface.

So no the ratchet is coming off.

KBs PensNmore
18th Sep 2018, 11:32 PM
Hi Baron
for getting a centre punch running true in the lathe I use a different kind of wobbler. The beauty is that I don't need a dial indicator. :)

Phil
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Sorry to hijack your thread John. Nice work by the way.
Phil could I have some more details on setting up your wobbler, please? Does the tool post have to be in a certain position, height, etc?
Thanks
Kryn

Steamwhisperer
19th Sep 2018, 07:29 AM
Phil could I have some more details on setting up your wobbler, please?
Kryn
Will do Kryn, I'll do a thread on it.

Phil

BaronJ
20th Sep 2018, 11:54 PM
Hi Guys,

Just making some last touches for the Norman Toolpost.

One of the things that I discovered was the end of the hight adjusting screw scratches the top of the topslide surface.
So I drilled out the end of the cap screw and made a brass tip for it. It also helped that the cap screw could have done with being a few mm longer. The brass tip added about 3 mm to the overall length.

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I used a pair of M6 nuts to lock the cap screw whilst I had it in the chuck jaws. As it happens the across flats distance is exactly the same as the head diameter. Very convenient for holding square in the chuck jaws whilst drilling.

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This is how I shaped the end ! The same router cutter that I used to round the edges of the tool block.
It is held in a bit of 1/2" square, drilled down the middle 1/4" to suit the cutter shank, and then hack sawed through so that it will close up
on the cutter when the pinch screw is tightened.

I now need to find a 50 mm long, M6 cap screw to go through the pinch clamp, for locking the holder to the post.

BaronJ
26th Sep 2018, 04:03 AM
Hi Guys,

The finale ! I've made the last items needed to finish off the Norman Toolpost.

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One of the items I needed to make was a 7/16" BSF nut. I found that the original ball handle got in the way, even with the original tool holder. So I decided that an oversized nut would be a good replacement. I knew that I had a very short length of free machining, 1" hex bar kicking about. So I chucked it up in the lathe three jaw and drilled it tapping size for 7/16" BSF. Fortunately I have the correct tap for this size. So no problem threading it.

I had to use a piece of square HSS to allow me to get it far enough out of the jaws, in order to round off the corners. I didn't take any pictures of this since I know that you have seen the pictures of me using carbide wood router bits as lathe tools. I did one half and then turned the work piece around to knock the corners off on the other side. A little bit of careful filing got rid of the little sharp bits that I couldn't get at on the lathe.

I don't know whether its just me or not, but this metal stinks when being machined...


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Even after I had completely de-burred the nut I was concerned that the edges would dig into the post fastened to the top slide, so I made a brass washer from a 30 mm square of 1.5 mm thick brass plate.

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Out with the wax chuck ! I used the 7/16" drill to bore the hole in the middle, and turned the brass down to 29 mm diameter.


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Here is the finished project, complete with a M6 cap screw for the split clamp. No it isn't on the wrong side. Its just easier to get at.

Thanks Guys.

Steamwhisperer
26th Sep 2018, 08:26 AM
Nice bit of work there John, functional and looks great.

Phil
(I must dig out my router bits)