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Member postings for Jed Martens

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

Thread: Warco GH600
18/03/2020 13:39:04

As Howard says, the chucks bolt onto the flange of the spindle, there is no thread. There are holes for both 3 and 4 bolt patterns.

For some reason the 4 jaw chuck was supplied with a back-plate, but the chuck will bolt directly to the flange, so I ditched the back-plate.

I use ER32 collets, and purchased a collect chuck from ARC. Again, this bolts directly to the spindle flange. So I haven't had to use back-plates at all.

The internal taper of the spindle is 4MT, but aside from a dead centre (supplied with the lathe) I haven't made use of this.

Jed

10/03/2020 15:43:32

I've never tried it (still trying to get the hang of right hand threads), but you can reverse the lead-screw direction relative to the spindel - ie: have the cutter move left to right when you engage the the half-nut. Does that result in a left-hand thread?

Thread: New member from Dunfermline
14/02/2020 22:18:07

We have a lot in common then Jim

13/02/2020 16:44:18

Hi Jim, I'm just down the road from you in Inverkeithing, and have a similar Warco lathe (GH600). If you need any help, just ask.

Jed

Thread: Warco GH600
08/02/2020 20:17:18

TB and Martin - thanks for the suggestion re: drilling the counter-sinks for the cap-head bolts. I think that in retrospect I should have done this (God knows I have enough chewed up drills to grind flat) and made the part from scratch.

Sadly patience isn't one of my few virtues. I spent the day going with my first idea...

I started with some stainless square stock that was about the right size, and used my rotary table to mill out a 12mm round shoulder. I would have used the lathe for this, but...

The shoulder was drilled and tapped to M8 (which I didn't get concentric, as you can see). The setup was a bit shonky, hence the poor finish. And the collets everywhere, and the swath.... it was one of those days...

20200208_145012.jpg

Note to self, when I can't find the spotting drill tomorrow, it's hiding in the t-slot...

As for the original plate, the chewed up M8 hole was drilled out to M12, and the new part inserted...

20200208_144953.jpg

The idea is that the thread engages where it did previously, but there are many more threads than before, and the plate underneath spreads the load, hopefully relieving pressure on the crack. I did manage to get a nice tight fit.

20200208_144958.jpg

 

The piccy above was before I ran some M3 screws through the part to fix it to the clamping plate. I added loctite for good measure, since I hope never to see this part again. Here it is fitted...

 

20200208_163456.jpg

It looks close to the lead screw, but there is plenty of clearance.

Here's the new "shoulder bolt" for locking...

20200208_163534.jpg

Ok it's just a regular bolt with a bushing, but it works well. It goes from loose to totally locked in less than half a turn, and it's a lot sturdier than the original.

There's still a lot of reassembly to do, but I've called it a day and opened a beer. In retrospect...

* I learnt a lot about how the lathe works.

* It was a great opportunity to give the lathe a decent clean

* The new clamp works better than the original, and should last a bit longer, given it was twice the number of threads. I also prefer using a spanner to lock the carriage, as I have plenty of spanners, but usually have to go looking for the alan key to lock the carriage with the old bolt. And I get more leverage with a spanner...

* It would have been a lot quicker to just make the part from scratch

* This was an entire day of my life I will never get back...

@Martin Wood, my fingers are shredded, there is no part in that thing that has been de-burred. If you have time to take it to bits and clean it up, it will be time well spent. On a positive note, the internals of the apron looked pretty clean and well made (not that I'm an expert), and it all came apart and went together again without issue. So I'm not complaning

 

Edited By Jed Martens on 08/02/2020 20:22:43

08/02/2020 10:27:11

So I managed to convince myself that removing the carriage would be easy enough...

And it was! Not as heavy as I feared either.

That was the good news. Bad news is that I still can't get at the locking plate...

One of the fixings is hidden behind a cast-in lug...

20200208_094131.jpg

So nothing for it but to take the apron off. Which is easy enough with the carriage already off the lathe...

So the offending part. Not just a stripped thread, but a chunk of the casting has chipped away...

20200208_095700.jpg

And to complete the picture, it has cracked through...

20200208_100052.jpg

So I'm glad I went to the trouble of removing the carriage and apron to get at the part, as it clearly needs properly repaired or replaced.

What to do?

* I can ask for replacement part and wait for it to arrive. Will the new one be any better than the old?

* Make a new one from scratch. I don't have the cutters to do the counter-sunk cap-head screws. And the mating surface with the under-side of the bed looks to be be ground, so perhaps this needs to be finished beyond what I can manage on the mill.

* Repair the part - there is a fair bit of clearance between the underside of the part and the lead screw - enough space to bolt on a chunk of something to give the part rigidity and drill/tap it to provide the locking function...

Any thoughts? I think I'm leaning towards repairing it at the moment...

 

Edited By Jed Martens on 08/02/2020 10:28:43

07/02/2020 19:35:57

Thanks guys, the helicoil is an interesting solution I hadn't considered. I've never used one, but the simplicity is tempting...

Another thought that occurred to me as I stared at the lathe this evening - is appears simple enough to removal the carriage entirely, which would give me direct access to the locking plate. If I remove the "thingy" (don't know the technical term) that holds the right-hand end of the lead screw I should be able to wind the carriage off the end of the bed. It is no doubt rather heavy, and there looks to be some gib screws that will need to be slackened off, but this seems to be quite a clean way of getting at the problem part. Or is it a daft idea? I've never removed the carriage before...

07/02/2020 14:30:06

A wee update, really enjoying the lathe, and still very much on the steep part of the learning curve, but starting to make some useful and accurate (albeit simple) parts.

However I now have to make my first repair, and I don't think it was my fault...

I've belatedly discovered what a good idea it is to lock the carriage when parting or making facing cuts, so the locking bolt (discussed earlier in this thread) has been getting a work-out. I noticed that it seemed to lose holding power, and then the cap-head bolt stopped tightening. It looked to have minimum thread engagement, so I replaced it with a longer bolt, which worked for a while, but now it's clear that I've stripped the threads.

The threads are in a steel plate that sits under the lathe bed, behind the apron, and is pulled up when you tighten the locking bolt. I can see a few ways of fixing and even improving the mechanism, but the big challenge is getting at it. I suspect I might have to remove the lead screw and/or the apron.

So first question - has anyone modded the locking plate or had it off? Any tips on how to get at it?

I managed to get a nut between the lead screw and locking plate, run a long bolt down to it, and tighten it all up. The saddle locked up rock solid. So I'm happy that the basic mechanism can work, it just needs some decent threads to you can really tighten it up.

Edited By Jed Martens on 07/02/2020 14:30:51

Thread: Moving a Sieg SX3 Mill
23/01/2020 15:09:50

I moved my sx3 from one shed to another by breaking it down, as Jason suggests. It is fairly easy to remove the table, and the column comes away from the base cleanly (need to remove 4 bolts, from memory). The head is easy to remove from the column but there are two cable conduits between the two. If you're comfortable around electrics it isn't hard to disconnect everything inside the column and detach the conduits, but it will take a little time.

Don't drop the column on the concrete floor like I did...

Thread: Has anyone watched this Girl
18/01/2020 21:31:30

As a novice I've found her videos for beginners to be very helpful. I enjoy the entertainment value of the popular youtube machinist channels (Abom, This Old Tony, et el), but Quinn's equipment and projects are much more appropriate for my level of experience.

Thread: DIY magnetic DRO
21/12/2019 15:46:46

And here it is fitted to the mill...

20191221_125829.jpg

18/12/2019 22:36:30

I decided to go ahead with my first idea. But only for the Y axis for now, as it's the shortest and if things don't work out, it's easy to replace the tape.

I machined the read head enclosure out of aluminium. I started with a drawing but ended up free-styling a lot of it.

20191218_095859.jpg

The bracket for the tape is pretty simple...

20191218_100033.jpg

I ordered some armoured cables from Machine Dro. I removed the DB9 from one end and drilled a hole to accept the cable sleeve in the read head body (10mm). This is retained with a M3 grub screw. The cable quality is very good - all connections individually sleeved, and good screening. 20191218_100045.jpg

Next, I bodged together the electronics with parts I scavenged from the left-overs bin in the office. It ain't pretty...

20191218_201634.jpg

But it works!

drogui.jpg

Ok, only the axis labelled "X" is live in the above GUI pic.I'm just moving the read head against the tape bracket by hand, but it increments in one direction, decrements in the other, and it changes by roughly what you would expect.

To be honest, it's all gone too well, so I'll stop now before something blows up. Next step is to fit it to the mill, and to consider how to tidy up all the electronics and mount it in some kind of enclosure.

Edited By Jed Martens on 18/12/2019 22:44:04

Edited By Jed Martens on 18/12/2019 22:51:02

Thread: Machining a curve
16/12/2019 15:58:15

Ok, done. Thanks for the prompt feedback.

16/12/2019 15:47:45

I'm trying to figure out how to make the part below. It's a "bell" that is used for crimping crown caps onto glass bottles. Most of it is simple turning and threading, but I'm not sure how to tackle the "bell mouth". My best guess so far so to successively approximate the curve using the compound, and then use some kind of abrasive to blend it together.

I don't think the exact nature of the curve is critical, just that it is smooth and gradual, and that the minimum internal diameter is spot on.

Is there a better way?

cap_bell.jpg

Thread: Slip gauges
15/12/2019 09:45:59

Thanks chaps, that's an impressive collection of advice in just 24 hours.

I appreciate the arguments for and against buying second hand, and I have no doubt that there are bargains to be had. But I don't have the experience to judge the quality of a second hand slip gauge, and given their role as a reference, I want to have confidence in them.

The gauge holders look interesting, and I can see how they would be useful. The holder itself appears simple to make, but am I correct in thinking that the jaws (placed either side of the gauge block stack) need to be of similar accuracy to the blocks?

Based upon the above advice, my feeling is that this 47 piece set will be more than adequate for my needs - cheaper than the ones I listed originally, and just the 5 micron block below 0.01mm accuracy.

47 piece set

Again, many thanks for all the input.

Jed

14/12/2019 08:49:03

I'm considering asking Santa for a set of slip gauges for Christmas. These will be for set-ups on the mill, checking the calibration of equipment, verify the accuracy of my work, etc. I think this means "workshop" grade (grade 2).

Are there any obvious pros/cons to look for?

If they claim compliance to some standard (eg: DIN861) can one consider the quality to be adequate?

Is 0.01mm resolution good enough, or are there reasons to go to 1 micron? My machines and measuring kit only go to 0.01mm...

Some of the sets I've been looking at...

88 piece set

56 piece set

Any advice gratefully received.

Thread: DIY magnetic DRO
28/11/2019 13:08:18

I've taken the plunge and ordered two read heads and tape, which I'll use for X/Y on my mill. If it's a success I'll roll it out to the mill Z axis, and maybe the lathe too.

I'm still pondering the pros and cons of the various ways to mount the tape to the table, thanks for the feed-back above. I like the simplicity of mounting the tape directly to the side of the table, and see the advantages of accessibility, but it makes mounting the read-head more challenging...

dro_side.jpg

I've ordered the aluminium to make the tape bracket, should I chose to go down that path, as it was cheap, but I'll probably wait until I have the read-head and tape before I decide.

For the electronics I'm planning to go full DIY. Something like...

* RS-422 receivers to convert differential signal from read head to 3.3v single-ended.

* Small programmable-logic card to count the pulses and present the data on an SPI interface. This is timing-critical "real time" stuff, which I don't like leaving to software.

* Raspberry Pi with touch-screen, reading SPI data and running a DRO GUI. The software will be written in Qt (a cross-platform C++ IDE with decent gui/widget support)

I've used similar set-ups for other DIY projects so I'm not having to figure much out from scratch.

On a slightly different topic, I note that RLS also make rotary magnetic tapes, which are used in conjunction with the same read heads. Given that electronic lead-screws are en vogue, has anyone used a magnetic encoder instead of rotary optical encoders to track the spindle position? I imagine that the rotary tape could be fitted directly to the back of the spindle, and monitored with no physical interface, removing the timing belts and pulleys that I've seen the guys on youtube use.

Thread: Warco GH600
25/11/2019 20:56:52

Yes, the mechanism that attaches the lever to the control shaft is shoogly, and it can be depressed beyond the detent if you're not careful.

I hadn't thought this an issue as the tray itself stops you pushing it too far, but failed to considered the case where the lever is beyond the end of the tray...

Edited By Jed Martens on 25/11/2019 20:57:58

25/11/2019 17:24:11

Ian wins the prize, that red ball in the middle of the picture is the culprit. I had the carriage close to the tail-stock end of the lathe, turning a piece that was about as long as the lathe can manage. The lever was depressed to start the lathe (with power feed towards the chuck), and since I was watching the work, I didn't notice the ball hooking under the edge of the stand.

@Triumphboy, very grateful for the offer of help, but I'm up in Scotland

@John I think you're right, the top sheet of the stand is lifted a little around the front right corner of the lathe bed, which will likely have an affect on how straight the bed is. The irony is that the work I was turning was supposed to be a test piece to help get things into alignment - I've yet to seriously tackle getting the lathe set up properly. So at least I haven't undone any previous work in that regard. But now I need to do some metal-bashing before I can get back to checking if everything is true.

24/11/2019 15:31:09

Good guess, but the lathe is immobile. There was no other object involved, all damage was self inflicted.

The metal beating advice is much appreciated, as it's something I've never attempted before. As you say, yet another skill to master

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