Member postings for Jed Martens

In other news, I had my first major oopsie with the lathe. I'm not sure if this a classic beginner's mistake, or my ineptitude is unique, but here's the result...

It's just bent sheet metal, that I might just be able to persuade back into shape. Does anyone care to guess how I managed it?

Edited By Jed Martens on 24/11/2019 14:20:24

Yep, that does make me feel a little better :D There's no mention of how to operate the lever in the manual (no surprise there) and the diagram on the apron only illustrates two positions, so unless you're familiar with these things from previous experience, it is easy to overlook. That's my excuse anyway...

I haven't got around to fettling the gibs and so forth yet, but given my first attempt at parting was a bit of a disaster, it sounds like I should get onto it.

@Brian, sorry I missed your explanation earlier, your input since I purchased the lathe has been much appreciated.

Thanks Bazyle - that explains it.

It still took a few seconds to figure it out. The lever appears to only have two positions - neutral and down (engages power cross feed). The third position is engaged by sliding it to the right and then up.

Thanks for the help

Jed

I agree, that seems to be the sensible explanation...

But how to change between those two scenarios? The machine only has the one driven lead screw...

Unless there's some change-wheel combination that isn't obvious, the values in the top table appear unobtainable...

I'm probably missing something simple here, but it's bugged me long enough to risk embarrassment on a public forum. I have no idea what the numbers in the top left table mean...

I'd always presumed they were feeds. In mm/s I would guess. There is a suggestion that facing is half the speed of turning, when using power feed, and that is indeed the case. But I can't make sense of the 0.044 figure (setting A1) for example.

What does make sense is the next table down, which is for thread cutting, and has a value of 0.25 for setting A1. The saddle does indeed move 0.25mm for each rotation of the spindle, I've checked with a dial indicator. I've also cut threads that work, so I'm pretty happy that the thread cutting table is correct.

But is 0.25mm / revolution the minimum feed rate? I was watching a youtube video where the machinist used a feed rate of 0.03mm / revolution, and checking the specs of his Emco 13 lathe, that is indeed the lower limit of feed rates. Is my minimum feed rate really ~ an order of magnitude higher?

It almost feels like there should be a change wheel or lever to switch between thread cutting and regular feeds. But I can't find a facility like that on the lathe.

Hopefully I'm just being daft and missing something simple. Humble pie is my favourite flavour

Edited By Jed Martens on 23/11/2019 20:52:12

I've been thinking about how to mount the magnetic tape and head to my mill. My idea is to make an aluminium bracket and bolt that to the x-axis of the table, with the tape on the underside facing down. The head will be under that facing up. As in the diagrams at the bottom of this post (apologies for my amateurish modelling).

Are there any obvious draw-backs to doing it this way? It seems that the whole ensemble is better protected from crude (and me dropping things on it), and the read head is easier to mount. I'll make an enclosure to fit over the read head too, similar to what Chris has done.

Hi Chris - how is your magnetic DRO system working? I've considering using the same components for adding a DRO to my mill. I think the version with integrated RS422 driver would works best my case (differential signalling having better noise immunity)...

My main question - do you see any issue with using the high accuracy versions (~1/4 micron per edge, 8192 edges per 2mm)? Assuming the electronics at the far end can cope with the data-rate of course. I know that the mill isn't that accurate (and the operator even less so) but I see no obvious reason for going with a coarser output.

Hi Triumphboy, I'm a novice too, so I can't address all of your questions. But I think you can lock the saddle - if you look to the left and right of the cross-slide there are are a pair of socket-head bolts that hold the apron to the saddle. But on the right there is a 3rd bolt, above the other two, that can be tightened to lock the saddle.

I haven't used it yet, as I fear that I'll forget I've locked it and then engage the power-feed...

You can also lock the compound, but I've not found any way to lock the cross-slide.

Best Regards

Jed

I believe they are ground flat. More info here...

**LINK**

I'm from NZ originally, but having lived in Scotland for ~20 years any advice I can give is out of date. I also had no interest in engineering/machining when I left, so there could well be a lot of stuff I never noticed. I don't think I ever used a train until I moved to the UK. Cars rule in NZ.

I'm from the Far North, so if you head up that way, one thing that springs to mind is the Bay of Islands Vintage Railway, opened in 1868 according to Wikipedia...

**LINK**]

The line runs straight down the middle of the main street of Kawakawa, which is about all the town is known for. The nearby towns of Paihia and Kerikeri are pleasant and have plenty of tourist facilities.

I second Niloch's advice, Kauri trees are fantastic. The largest of them all is not far from the Bay of Islands...

**LINK**

The Far North remains one of NZ's poorest regions, but if you want to get off the beaten track it has plenty to offer. PM me if you'd like specific recommendations.

Jed

70.2 x 63.5 x 16.1 mm

Here's the main body of the tool holder

The square body of the holder is 66mm across. The bore is 38mm. That leaves 16mm of wall. The base is 20mm thick

@David, I don't mind you saying at all. I'm new to this and any advice is gratefully received. The tool had been fitted for the purpose of evaluating the centre-height, and hasn't been used for any real cutting. I'll adjust it before I do so.

@Ian, I don't understand the difference between the two models, so I just went with the one referenced in the MEW article.

I'm pretty ignorant about difference material types. It certainly isn't aluminium. I don't think it's cast iron. I guess it must be steel

I'll take some measurements for you, but I'd say that there is plenty of material to machine. The base which I had to bore through is a little thicker than the height of the compound post shoulder.

I didn't last very long shimming tools in the tool-post that came with the lathe, and ordered a qctp from Arc Euro...

**LINK**

There was a helpful article in MEW detailing how the tool-post was fitted to a Chester lathe. My lathe has a different kind of compound, but it was still helpful to get an insight into how the tool-post was fixed.

**LINK**

Here is the GH600 compound - it has a fixing post that is M10, and has a shoulder at the bottom that is wider (22mm from memory)

The tool-post fixes via a 16mm rod, and it comes with a base-plate that the rod screws into. I believe the idea is to machine the base-plate and slot that into the compound, but my compound has no t-slot...

So instead I cut the 16mm rod to an appropriate length and drilled a deep hole that was internally threaded M10 at the end....

This screwed down onto the compound post. Next, I had to bore the base of the tool-post so that it cleared the 22mm shoulder.

That was no fun at all. My mill was struggling with the cheap boring head and chattering like crazy. I got there in the end, and the surface finish is rubbish, but it's a better fit than the original tool-post holder.

And here it is fitted...

There was one last problem. Some of my tooling was still above the centre-line, even with the holder at its lowest setting, so I had to mill a few millimetres from the bottom of the holder.

It all appears to work as expected. My nerves were shot after drilling the rod and boring the tool-post, as it was my first time doing those kind of operations, and any mistake could well be costly. But I am happy with the results.

There's a cross-slide lock??? I found the compound lock, but I didn't realise there might be one for the cross-slide (stop laughing, it's my first lathe). If there is, the combination of a lock and power feed spells trouble...

Nice work with the base. Puts my concrete slabs to shame :D

Thanks for that Brian, I'd spotted that the spurious gear (as opposed to a spur gear) had 48 teeth, as referenced by the splash-back diagram, but it also referenced a 42 tooth gear, and I had no idea where that was. The threading indicator explains it all (unlike the diagram, or the manual)

Cheers

Jed

I had the same issue when using my warco gh600 for the first time. I found that setting the compound to 45 degrees (which means rotating the toolpost the opposite 45 degrees to compensate) has the effect of moving the cutter forward and to the right. This gave me just enough room to engage the dead-centre without running into the carriage with the tailstock.

Obviously this isn't helpful if you're trying to use the compound for cutting tapers or the like.

Jed

Here it is in place...

Still a bit of work to be done. I'be put some machine feet on the stand so that I can bring it up to a comfortable height. I'm not happy with how high they are. I'm going to put some concrete slabs under the feet so that they are at a minimal height, but still offer some adjustment. Then I need to ensure everything is twist-free.

But I couldn't wait any longer to try it. My first project is a part for a friend's motorcycle stand. It's simple and in aluminium, so a good starter project. Here it is half-done...

I've taken it out of the 3 jaw because I need to flip it. I'll put the 4-jaw on the lathe tomorrow and see how much fun it is getting it to run true.

Aha! Can't remember where I found mine, but I'm pretty sure it wasn't under the foot. I guess they randomly toss one into every crate before nailing the lid down