Boxford model A gears

[john barnes 4Participant @johnbarnes4]

Hi all, I need a couple of gears for my Boxford model A gearbox. I have identified them as 16dp using the formula – number of teeth plus 2 divided by diameter. Can anyone confirm that is correct. Also does anyone know the pressure angle.

[john barnes 4Participant @johnbarnes4]

[larneyinParticipant @larneyin]

I think the gears are 18 D.P. with a 14.5-degree pressure angle and 0.125" depth of tooth. They are 3/8" wide, have a 9/16" bore, and have a 1/8" keyway.

I stand to be corrected on this and suggest you wait for others to confirm, or otherwise

[larneyinParticipant @larneyin]

Oops! On re-reading the post I see it is the gearbox gears you need the info for, not the change gears.

Sorry for for not reading the original post correctly

[larry phelan 1Participant @larryphelan1]

You know what they say "Read twice, comment once" or something like that !!

No offence intended, Larneyin, just could not resist it ???

[BazyleParticipant @bazyle]

The normal changewheels are 18DP, the back gear cogs are 16DP but I've no idea what the ones internal to the gearbox are. If you have it apart try running a gear with the ones mentioned above and it should confirm either way.

[Brian WoodParticipant @brianwood45127]

If it's any help, when I overhauled my Smart and Brown Sabel on purchase, [their clone of the Southbend lathe], the gears in the gearbox were all 16 DP and at that age they would be 14.5 degree pressure angle.

I imagine Boxford followed the design in that respect as well.

Regards Brian

Edited By Brian Wood on 16/07/2020 09:18:28

[larneyinParticipant @larneyin]

Larry

Fair comment – I can only plead advancing (even advanced) years in mitigation

Tommy

[William ChithamParticipant @williamchitham75949]

There was a thread on this topic recently: **LINK**

William.

[larry phelan 1Participant @larryphelan1]

Hi Larneyin,

Welcome to the club. The older you get, the worse it gets, trust me !, I ,m well advanced at this stage.

I need to keep two pairs of reading glasses around all the time, to be sure of finding at least one set when required, and I,m only 82 and a bit !

I hate to think what I,ll be like when I get REALLY OLD !!!

[john barnes 4Participant @johnbarnes4]

Thanks for all the replies guys. I know the gearbox gears are definitely not 18dp because they would not mesh with my change gears when I stripped the gearbox last weekend. Unfortunately I can not try them with my back gears as Bazyle suggested because the gearbox is now reassembled and re fitted. I assumed the back gears were the same as the change gears. I am leaning towards 16dp and 14.5 degree pressure angle. I am going to try Williams link to confirm pressure angle. If I am correct does that mean I can use Myford gears. I know they will need to be adapted but they seem more readily available and much cheaper.

[Brian WoodParticipant @brianwood45127]

John,

Myford gears are 20 DP so they will definitely not mesh with the 16 DP gearbox gears.

Regards Brian

[john barnes 4Participant @johnbarnes4]

Thanks for that info Brian. I have had a quick look for the gears that I think I need. One in particular seems very uncommon. It may be cheaper and quicker to make my own.

[not done it yetParticipant @notdoneityet]

Raglan and Drummond, amongst others, used 16DP with 14.5 PA change wheels. Presumably they would need keyways cutting, if hard enough. Both were 16mm bore and 3/8” thick, I think.

Give us a clue of tooth count required?  And any other pertinent detals.

Edited By not done it yet on 16/07/2020 23:31:46

[Keith LongParticipant @keithlong89920]

Posted by not done it yet on 16/07/2020 23:31:00:

………Drummond, amongst others, used 16DP with 14.5 PA change wheels.

No, Drummond used 14DP with 14.5 deg PA.

[john barnes 4Participant @johnbarnes4]

I have been searching for gears using Boxford as a keyword but I am going to omit Boxford from my searches from now on just in case there is another maker such as Raglan or Drummond using 16dp gears. The gear I want to replace is a 16 tooth / 32 tooth combination. I also have a couple of 32 tooth gears showing signs of wear which I will change if I can find them cheap enough or can find the cutters I need to make them. The gearbox was dismantled and all gears cleaned and deburred where necessary, oiled and replaced. It is working better than it was but when the 16 / 32 combination is selected it sounds noisy and feels rough. I wish I had taken pictures of the strip down so you could see the damage but it did not occur to me.

[Brian WoodParticipant @brianwood45127]

Hello John,

Here's a suggestion.

There are two combination gears [16/32 teeth] in the doubling gearing part of the gearbox. The noisy one has perhaps had a lot of use and you could perhaps put off the day when action has to be taken by swapping them over

Regards Brian

[john barnes 4Participant @johnbarnes4]

Hi Brian, I am not absolutely sure but I think one pair of gears is keyed and the other pair not. I tend to avoid using the bad gear unless I need it for screwcutting.

John

[Brian WoodParticipant @brianwood45127]

Hello John,

You could well be right, it is several years since I rebuilt the Sabel gearbox and I could easily have forgotten that small but important detail.

Sorry if I have raised your hopes prematurely

Regards Brian

[john barnes 4Participant @johnbarnes4]

No need to apologise Brian I welcome your input.

John

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