Member postings for AJAX

Oh, I think I may have misunderstood. Did you mean the hole in the hand-operated lever or the cradle that holds the worm gear?

Pete, it's a good fit. However, I don't rule out the possibility of making a modified pin in the future. Have also considered drilling through and tapping so I can adjust the pressure.

As promised earlier, here is a bit of an update.

The lathe is currently stripped down so I am unable to test the powered feed under load. However, I have reversed the unevenly worn worm and made a "temporary feedshaft" (turned to size at work and then milled the slot at home) so I can see what is happening. When I did this it was quite obvious the worm was not being lifted sufficiently to engage with the worm wheel.

There is a lever-operated cam at the front of the apron which lifts the worm mechanism via a pin; I have now added a spring behind the pin to make sure that it engages positively. This has greatly improved the action and the lift. Turning the feedshaft over by hand it all appears to work well; the visual signs and "feel" suggest good gear engagement.

I should have the lathe back together and under power to test in a few days time. The temporary feedshaft will make it infinitely easier to get the lathe back together (the temporary will slide out as the real one pushes in) and means I'm quite happy to pull it all apart again when I turn a replacement worm.

Thanks for your interest and advice.

Brian

Still need to swap gears with the full gearbox? I will have to download a manual as I am unfamiliar with the lathe apart from basic tasks.

The replies on Denford Data and this website have been very useful.

I nipped into work today to borrow a lathe and turn that temporary "feedshaft" so I can test the feed gears with the apron away from the lathe. I noticed their lathe (Harrison ML300) is turning a taper and so presumably the tailstock needs adjusting. Like most equipment there, it doesn't get used. However, I'm not getting involved with that as I have enough jobs to do!

I've finished cleaning up the apron which was thick with an awful paint that had been slapped on top. At least it looks nice.

I will report back in due course.

Martin,

I think that you and the others have raised valid points that need to be considered. It has been difficult to diagnose this problem with the apron assembled and in place as the gears are not not visible. e.g. Is it worn gears, poor meshing, or bad locking mechanism?

When the apron is removed, the feedshaft is no longer in place to hold the gears and see what is happening. What I have decided to do is to turn a short length of "dummy feedshaft" (doesn't need to be particularly accurate) to hold the gears in position when the apron is removed from the lathe. I can then turn it over by hand with the gears in full view. I should then be in a much better position to know what is happening.

Ady and Pete,

I see your point. Actually when I first tried the rotary lever I had the very feeling it wasn't engaging properly. Maybe that's why the worm became worn and not the other way round. I will take another look over the weekend. Let's hope for some warmer weather as my garage is FREEZING!

Brian

Thanks for confirming that. I took some measurements in case anyone is interested.

Pete,

Please excuse my questions.. I'm a novice.

You mentioned 1.098" worm diameter. I assume you got that from (0.429"R + 0.120" tooth depth) * 2 which equals 1.098" or 27.89mm

The least worn diameter of the worm measures slightly less at 27.63mm. Looking at the working drawing should we also take the specified clearance into account when calculating the worm diameter?

Reversing the worm... Great idea! It's definitely worth a try.

Thanks for your suggestion but I don't think so.

Thank you Pete.

Good advice and pretty much what I would have guessed but I can see this ending up as more expensive than the lathe itself. Maybe I might strike lucky and see a whole apron assembly for sale somewhere. Or perhaps one day I may have the skills to make these parts.

As an aside, I'm not totally convinced it is necessary to get the feed shaft working (which requires a good worm and worm wheel). A working feed shaft can power the cross feed (nice feature, but not absolutely necessary) but the separate lead screw and half nuts already work All I need is some more gears or an electronic drive to make it more usable.

I have a long-overdue job that needs to be done to restore this lathe. The feedshaft worm is badly worn and spares appear unavailable. I've been on the Denford Data website where there appears to be a number of knowledgeable and helpful guys and I'm hopeful that I can get the original drawings for the worm. With or without the drawings I would like to get a new worm sourced or made and I'm wondering if anyone can make a suitable recommendation. I'd expect to pay a fair rate but we have to be realistic as this is not a top-end lathe.

Incidentally, by visual inspection it is my presumption the worn worm is the cause of partial engagement (and unwanted disengagement). The worm wheel looks to be in much better condition but it remains in the gearbox and taking a photo is tricky at present. However, I would have expected the worm wheel to wear at a faster rate than the worm but maybe I've got that wrong.

I'm based in Dorset.

Thanks for reading,

Brian

I've been scouring the Internet and found a photo that shows the top slide assembly disassembled. Curiously, I still can't see anything that is holding the compound slide in place. Maybe oil and suction? I'll have to take another look tomorrow.

The photo:

http://www.denfordata.com/bb/download/file.php?id=44

Found in this topic:

http://www.denfordata.com/bb/viewtopic.php?t=457

In my quest to semi-restore (not too interested in paint jobs) and improve the function of my Denford Viceroy lathe I am part-way through dismantling the cross slide, apron and compound slide.

Despite close inspection, I cannot see what stops me separating the swiveling compound slide from the cross slide. The three grub screws that are used to lock rotation are now fully removed. It swivels freely. The compound slide lifts away from the cross slide by a few mm but is clearly being retained by something. But what?

Apart from that, the dismantling is going well. I had to knock out a couple more pins (see my previous thread) but these were much easier and there were no substitute roll pins this time.

You can buy those link belts on eBay - no need to purchase 7.6m

They cost about £18 per metre.

I bought some for my Denford lathe and they work just fine.