Wadkin AGS fine fence adjust dimensions help

[merlin]

Looks like there might be one on the Bay at the moment, expensive but....

 

[deema]

Wow, thank you so much for posting the pictures and making the measurements. That is a very clean almost new looking gear. Your saw looks really nice. Yours is the last version of the saw, mine is an earlier model. However I believe the fine adjuster was a common part across all generations of the saw.

I didn’t remeasure the OD of the gear, just the root. The hole it fits through is definitely 1/2” (ish) I’ve bought new oilite bushes, which are specified in the manual and they are a good friction fit

 

[deema]

This morning, I had arranged to collect from a near by friend (Observing social distancing.....it was left out) his fine fence adjusting knob for comparison.

The OD of the gear on the one I’ve borrowed is 12.66, so very very close to KT, so around that number is the right size. The root of the splines was 9.9! Length of splined is 19.2. So slightly different, but that could be because the end has worn off.

I’ve photoed the borrowed spline (left) and mine (right) that I shortened the splined section as it was so badly damaged on the tip. To make it work, I’ve had to extend the shaft by not putting the handle on as far. Its had a hard life and the shaft is also bent which is why I want to make another.

I’ve attached a photo of the rack with my Very Near measurement.

 

[J-G]

The OD of the gear on the one I’ve borrowed is 12.66, so very very close to KT, so around that number is the right size. The root of the splines was 9.9! Length of splined is 19.2. So slightly different, but that could be because the end has worn off.

The length is irrelevant as far as the gear shape is concerned of course and the 9.9mm dia root makes me consider that it is a 20ºPA STUB Involute form but again that is somewhat academic since the rack doesn't look to be full form either. It is also possible that Wadkin modified the detail but retained the 14T 32DP.

I've thought about the 'about 10 teeth per inch' on the rack and have to apologize I did question my assertion that the DP number was equivalent to the number of teeth per inch and even deleted it from my message but re-entered it on checking a technical paper which agreed. That was totally wrong (hammer) and I ought to have trusted my own tables/spread-sheet which shows the Circular Pitch to be 0.098175" ie. less than 2 thou away from 1/10". (I'll blame the late night/early morning working )

The images from KT_NorCal are useful in-as-much-as they show a near pristine version but without a photo of the rack doesn't help us in determining the PA which I now think is more likely to be 20º.

I doubt that I'm going to be any further help but am pleased to have fuelled your interest in gears/gearing - it really is a fascinating subject and you may like to get hold of a copy of "Gears for small mechanisms" by W.O.Davis which has a wealth of detailed information. That certainly help me when I was designing an internal planetary gear system for a cylinder clock.

 

[deema]

Thank you JG for all of your help, really appreciate it.

 

[J-G]

Thank you JG for all of your help, really appreciate it.

You're more than welcome deema. It's been an interesting exercise.

I do hope you are successful in affecting a repair, be it DIY or expensive purchase

 

[KT_NorCal]

The images from KT_NorCal are useful in-as-much-as they show a near pristine version but without a photo of the rack doesn't help us in determining the PA which I now think is more likely to be 20º.

I actually can take a pic of the rack as well if needed. I just happen to have it in a piece of cut off drain pipe full of a very dilute citric acid solution at the moment, so when I pull it out sometime tomorrow I can get a quick picture of it. Do you need it to show anything in particular? or just the ground in "cogs" on the underside?

 

[J-G]

The images from KT_NorCal are useful in-as-much-as they show a near pristine version but without a photo of the rack doesn't help us in determining the PA which I now think is more likely to be 20º.

I actually can take a pic of the rack as well if needed. I just happen to have it in a piece of cut off drain pipe full of a very dilute citric acid solution at the moment, so when I pull it out sometime tomorrow I can get a quick picture of it. Do you need it to show anything in particular? or just the ground in "cogs" on the underside?

A clear close up looking directly across the rack would be ideal.

Here is an image showing the angle - alpha - that we're trying to determine.

This is of course an 'ideal' basic drawing and the reality will probably have some curvature, either by design or due to wear.

 

[Farmer Giles]

AMS sell them, 96 quid plus VAT though.....

 

[deema]

Thanks FG, I hadn’t actually seen you could buy them........I’ve made a note as a back up solution. But where is the fun in just buying one when I’ve learned so much about gears and will hopefully make one.

 

[J-G]

Thanks FG, I hadn’t actually seen you could buy them........I’ve made a note as a back up solution. But where is the fun in just buying one when I’ve learned so much about gears and will hopefully make one.

There's one on eBay at £85 + £5p&p but it's an auction.

Whether there will be any bids is moot

Getting a 14-16T Involute cutter and learning to use your Dividing Head will be much more valuable in the long run though.

 

[deema]

Hi KT
If you could photograph and if poss determine the angle that would be highly appreciated

 

[Myfordman]

My suggestion to determine the PA would be to turn a taper of 20 and 14.5 degrees on each end of a small off cut of bar. Dont turn to a point but leave a blunt end such that you can offer it up to the rack just without it bottoming. With a good light and maybe an eyepiece, see which end is the best fit in the rack teeth.

 

[DBT85]

Things like this is what might put me off getting one of these great older machines over something newer.

 

[deema]

Thanks Myfordman, that’s a really cleaver suggestion. I will give it a go.

 

[deema]

Things like this is what might put me off getting one of these great older machines over something newer.

I wouldn’t be out of buying old iron. I knew it had a doggy micro adjust when I bought the machine, the price reflected it. I could have just sent the part to a machine shop and had one made (if I hadn’t learnt that I can buy one from daltons) I’m wanting to learn to use my mill, as well as enjoying getting a far better understanding of gears. This journey for me is real fun.

 

[DBT85]

Things like this is what might put me off getting one of these great older machines over something newer.

I wouldn’t be out of buying old iron. I knew it had a doggy micro adjust when I bought the machine, the price reflected it. I could have just sent the part to a machine shop and had one made (if I hadn’t learnt that I can buy one from daltons) I’m wanting to learn to use my mill, as well as enjoying getting a far better understanding of gears. This journey for me is real fun.

Oh OK so it's not basically unobtanium?

For me too the journey is as much a part of it, but with no lathe or knowledge of anyone with one, I'd have to resort to buying one and other parts like it.

I'd much rather drop a few hundred on one of these or a startrite than a used Sip or something for the same money.

 

[KT_NorCal]

Hi KT
If you could photograph and if poss determine the angle that would be highly appreciated

I got busy with all kinds of stupid random stuff, but I'll have time to take some nice pictures this weekend. I'm not sure I would be able to get the angle, but I should be able to get the measurements between the "cogs" and it should be able to be worked out from that. They were smaller than i remembered though that is for sure. My machine also came with a "second" rail which I have no idea why it was on the saw, so I'll compare them as well.

KT

 

[KT_NorCal]

So, the "cogs" (for lack of a better word) were much finer than I remembered. My Google Pixel 3 camera doesn't have a 'macro' or whatever you call the close up mode. I'll see if I can get my digital camera to get a better close up tomorrow when there is better light. There was a marine layer over the Bay area most of today so it was a bit overcast. Added some pictures of what I was able to get for you.

I know there was a lot of a very detailed discussion about proper ratios for gears at whatnot, but to my eye these look straight cut... They were too fine to get my calipers in there unfortunately, so I can't prove that one way or another at the moment. My fence rail does not look to be worn down in any way and I can still see machining marks on them so I'm guessing what you see with this is what you got originally....

KT

 

[deema]

That looks a beautiful rail that’s brand new!
I really appreciate the pictures, thank you so much.
The rack does indeed look to be straight cut! It looks to have had two cuts to make each slot, as there appears to be a slight ridge in the bottom of the gullet.

My initial impression of the cog was that it had straight cut teeth, but I thought that Wadkin would have used a proper tooth firm.