Randa lathe missing back gear

[Reggie ChantParticipant @reggiechant34558]

Ok cheers nick. I just think it's my best solution. Thanks again for your help and patience.

Reggie

[Reggie ChantParticipant @reggiechant34558]

Actually can I confirm something is a myford 60t change wheel the same as a Randa a 60t change wheel?

[Reggie ChantParticipant @reggiechant34558]

As far as I can see online the measurements seem the same. Not sure on OD though. My change wheel that came with the lathe fits the back gear fine I just don't want to use that one through fear of messing up the thread that I will have to create.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Reggie, the only difference between the Myford change wheels and the RandA change wheels is that the Myford ones have a keyway to drive them and the RandA ones have a small hole for a pin to drive them, which you would have to put in a Myford one if you need to replace any of your change wheels. The 60 tooth change wheel will fit as you say, but the teeth will not be in the gear on the cone pulley to the proper depth, it might only seem a small amount but when using the backgear, you will have the full load of the whatever you are turning and any load on the leadscrew which could result in broken teeth on your change wheel and don't forget, these are slightly thinner than the original wheel. This is why you should check the O/D of your 60 tooth change wheel and the Bull wheel you have on the spindle that is driven by the small wheel of the backgear. If you find the Bull wheel is bigger than the change wheel (as I suspect you will) then you will probably find a Myford 62 tooth one a better bet even if you have to fettle it a bit. A 61 tooth one would be a little better than a 60, but is still a bit shy. However the call is yours.

Regards Nick.

[Reggie ChantParticipant @reggiechant34558]

Ok thanks nick. You have been very helpful so thanks again

[TigerParticipant @tiger]

Hmmm… I just acquired a RandA today. It was on facebook for more then a week. Just wondering if you missed it or you sold it to me?

[Ady1Participant @ady1]

I just had a look at my Drummond M arrangement and I'm 99% sure that my backgear arrangement is exactly the same as my spindle arrangement

but in reverse

Would make production easier and cheaper

There's a good chance yours is exactly the same

Edit: Bullwheel gears and backgear gears tend to be chunkier than change gears because they have to do harder work than change gears, the teeth are stronger and can be slightly wider to help cope with higher loads

That being said, using change gears would save you an awful lot of work and get you to first base

GL

Edited By Ady1 on 04/10/2020 01:50:22

[Reggie ChantParticipant @reggiechant34558]

No I did not sell it. My old man brought it for me because I wanted to learn. I try not to sell gifts. I'm just going to wait for the right part to turn up. Working on building a countershaft for it when my 1 yr old lets me. Sadly she goes for anything sharp and dangerous.

I'm not on Facebook. I used to be but it started to annoy me although that was about 8 yrs ago maybe Facebook is better now.

I can live without a back gear and I don't mind waiting for the right part to surface.

[Ady1Participant @ady1]

Posted by Reggie Chant on 07/10/2020 17:36:24:

I can live without a back gear and I don't mind waiting for the right part to surface.

Well worth getting backgear fitted for the torque

It turns your lathe from a turning machine into a metal muncher

[Reggie ChantParticipant @reggiechant34558]

Ha yes metal muncher. I will get one as I hate incomplete things and I want this lathe to be the best it can be. A case of waiting for the right part to rear it's head.

[BazyleParticipant @bazyle]

FYI there is quite a nice complete unbadged one on ebay today but notice the first backgear is thiner so I think it has also been replaced during the v-belt conversion. When you think about the potential weak point if someone locks the backgear to undo the chuck it is this gear that will take the force so probably are lots of them out there with one broken tooth.

eBay item number:

254833902453

[Reggie ChantParticipant @reggiechant34558]

Hi bazyle. I have seen it, but could tell that the gear was too thin for my lathe. I have been keeping my eyes peeled. I have been using it fine without the back gear but really need to find one. I have to just wait till one appears.

Managed to source a counter shaft and put correct belts on. I even have a spare change gear but I don't want to fit as a back gear as it looks to thin.

One day the correct elusive back gear will appear

[Mario JonesParticipant @mariojones44715]

Hi all I've just acquired my first lathe it's a RandA and I'm currently establishing if I have any missing parts hence reviving this thread instead of starting a new one, trust that's okay.

So I'm missing the back gear shaft I think that's the correct terminology and wondered if anyone would be kind enough to provide me a sketch/dimensions so I can make a replacement.

Also what grade of steel would be required for the shaft and does it need to be hardened?

Thanks in advance.

Mario

[bernard towersParticipant @bernardtowers37738]

Out of interest flat drive belts are still made, they are made from a modern oil proof material and usually coloured green. Try transmission suppliers/ bearing suppliers like Hayley’s etc.

[Mario JonesParticipant @mariojones44715]

I have a belt that came with the lathe and the main spindle including the chuck and three pulleys, there's also a gear on the end. I also have a secondary/lay shaft with three timber pulleys run off a motor with a further three pulleys so there's plenty of options to change speed.

I spent a couple of hours cleaning, oiling and adjusting everything and set the lathe up temporarily on my work bench she runs great.

Also just ordered some spindle oil as I really have no idea what I'm doing and learning as I go, I could see the holes and worked out it must be for oil to lubricate the bushes, in fact I was surprised to learn it didn't run on conventional bearings.

For now I loosened the spindle clamps, washed the oil ways through with WD40 and compressed air several times and put a drop of 30w engine oil with just a spec of WD40 to thin it slightly just so I could try running her. I've adjusted the clamps and end float C nuts to the point where you can just by feel find a little play, I read this was req'd to leave a small margin for expansion due to heat and to check by touch for heat in the spindle carriage after running. I think I have it set perfectly to be fair I'm fairly good in terms of thinking things through and working out how things work etc but still have a lot to learn.

Anyway back to the main topic I am certainly missing the back gear shaft although the change wheels appear to be complete and present. One problem though the main change wheel 60t I believe that engages with the spindle gear has two missing teeth, but I'm fairly sure I can get this repaired.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Mario, do you have the swivelling bush that the backgear shaft runs in? which is shown in the photo below.

The shaft is 5 / 8" in diameter and is precision ground but it is not hardened and a piece of silver steel as purchased should be OK or even something like EN8. I will have a measure up of my father's old one and get the length and the size of the gears and post them later.

Regards Nick.

Edited By Nicholas Farr on 07/07/2021 13:55:28

[Mario JonesParticipant @mariojones44715]

Hi Nick,

Yes I do have the swivel bushing as your picture, if you can spare the time to have a measure up that would be great & thank you. I'm sure the information you provide will also be useful to others who happen upon this thread and may help keep more of these lathes in service.

I'll try to work out how to post some pictures of the lathe I have so you can see what I'm working with.

[Howard LewisParticipant @howardlewis46836]

When you are searching for a gear, it is important to know the dimensions, but also the DP and Pressure Angle.

Gears with different DP will not mesh properly, if at all.

Gears with different Pressure Angles will not mesh properly.

Take a gear, count then teeth.

Measure OD of the gear in Inches (Teeth +2 ) /OD = DP.

You will not be able to measure the Pressure Angle, so you need gears of similar vintage

Modern gears will be 20 degree P A, so not suitable.

Drummond, or Myford gears will, be 14.5 degrees. Myford gears will be 20 DP. Gears for the 7 Series will have a keyway, so you will need to drill a hole, partway through for the driving pin.

In this way 7 Series gears can be used on the earlier ML1, 2, 3 and 4 lathes.

If you can find a gear of the right DP, PA and width, you may be able to modify to fit your lathe mby either boring out, or by bushing the centre.

Howard

[Mario JonesParticipant @mariojones44715]

Some Pictures

Edited By Mario Jones on 07/07/2021 17:05:00

[Mario JonesParticipant @mariojones44715]

Posted by Howard Lewis on 07/07/2021 16:34:29:

Drummond, or Myford gears will, be 14.5 degrees. Myford gears will be 20 DP. Gears for the 7 Series will have a keyway, so you will need to drill a hole, partway through for the driving pin.

In this way 7 Series gears can be used on the earlier ML1, 2, 3 and 4 lathes.

If you can find a gear of the right DP, PA and width, you may be able to modify to fit your lathe mby either boring out, or by bushing the centre.

Howard

Hello Howard thanks for the info, re My Ford change gears I have a set that came with the lathe, they seem to mesh with the RandA gears fine but as you said they have a key way not a hole.

[Mario JonesParticipant @mariojones44715]

I can't seem to work out how to get the images to display?

Seem to have worked it out now.

Edited By Mario Jones on 07/07/2021 17:06:58

[Mario JonesParticipant @mariojones44715]

Posted by Mario Jones on 07/07/2021 16:11:12:

Hi Nick,

Yes I do have the swivel bushing as your picture, if you can spare the time to have a measure up that would be great & thank you. I'm sure the information you provide will also be useful to others who happen upon this thread and may help keep more of these lathes in service.

I'll try to work out how to post some pictures of the lathe I have so you can see what I'm working with.

Nick would this bar do the trick?

**LINK**

[Howard LewisParticipant @howardlewis46836]

Gears for the Myford 7 Series are more likely to be available, so if you have one gear with a hole for the driving pin, it can be drilled through and used as a template to drill the Myford 7 Series gears. with both mounted on a 5/8" diameter (From memory ) shaft.

When I did this, the hole was positioned opposite the keyway.

Howard

[Mario JonesParticipant @mariojones44715]

Thanks Howard that makes sense.

Nigel apologies if you have taken the time to measure the spindle I was digging through the bits and pieces I have with the lathe and pretty sure I've happened upon the missing spindle.

Athough I do appear to be missing a pin from the change gear arm.

[Mario JonesParticipant @mariojones44715]

It only bloody works 🙂

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