45 Tooth changewheel

Boston Gear do 14.5 degree gears, but they don't list 11DP - only 10 and 12 - I haven't come across an odd size before. Although they are States based they have UK distributors. I recall this came up in an earlier thread which you'll probably find by searching the newsgroup, but all their stuff is listed via their website. Are you sure these are

Steve

Steve

I was thinking the same thing about 11DP. Can you post a few OD's and tooth numbers so we can check. They might even be that so they were a proprietary part, at 1" wide they must be a decent sized gear. I have a drawer full of older change wheels, many off dividing head trains and one of these may do if we can determine sizes.

-- Regards,

John Stevenson Nottingham, England.

Visit the new Model Engineering adverts page at:-

I've got 11dp cutters, nos 2 & 3 in 14.5 deg, if you're really stuck I could make you a gear or maybe make some arrangement for you to borrow (hire ) the cutter.

Cheers

Tim Dutton Dry-Dock Traditional & Modern canal craft repairs Vintage diesel engine service

In message , John Stevenson writes

Thanks for all your suggestions, I have measured the diameter of the change wheels that came with the lathe, they are however an incomplete set when compared to the threading charts attached to the lathe gearbox.

The diameter of the 57t and 63t may be a little bit out as there are no teeth directly opposite each other (so a best guess).

I would be grateful if someone could check my calcs that they are 11DP.

Measuring the pressure angle I found difficult, I took one of the larger wheels and with a straight edge projected as best I could the angle of one tooth to the opposite side of the gear, then measured the angle between the projected line and a diameter taken from the root of the same tooth, I got something like 13 or 14 degrees so assume it is a standard 14.5 degree, it seemed well off 20 degrees so unlikely to be that.

Incidentally, I need a 45t gear wheel in order to cut 1.5mm pitch threads, the lathe setup suggested uses the 20tpi gearbox setting modified with a compound gear train of 45/60 and 63/40. The leadscrew is 0.25 inch pitch. Any help you can offer much appreciated.

Regards Ian

I make it 11 dp on a couple of your figures, haven't gone through them all

Tim

Dutton Dry-Dock Traditional & Modern canal craft repairs Vintage diesel engine service

Certainly looks like 11DP

The only suggestion I have that won't cost lots of money is Ivan Law's gear cutting book and the manufacture of some gear cutters. This is what I may well be doing for the 22DP stub form gears for My Hardinge project. Of course, John may come up with something from his box of bits!

Mark Rand RTFM

Hi Ian

Wouldn't using 60/80 be an acceptable substitute for 45/60. (space permitting)

Regards

Russell

Ian

Did you get my email?

Tim

Dutton Dry-Dock Traditional & Modern canal craft repairs Vintage diesel engine service

Ian, Had a look but no joy. The stack I have are 12 DP, probably off dividing heads and there was no 45 anyway, sorry.

-- Regards,

John Stevenson Nottingham, England.

Visit the new Model Engineering adverts page at:-

In message , Tim Leech writes

Hi Tim

Thank you for the offer of cutter hire or making a 45t gear for me. Can I put this on hold for a bit as Russell has come up with a cunning alternative, using a 60/80 gear setup rather than 45/60. I will check to see if these sizes will go onto the quadrant of my lathe first as I already have an 80t gear. Will report back if I may on results obtained.

Many thanks

Many thanks for looking John - much appreciated.

In message , Russell writes

SNIP

Russell

Great bit of lateral thinking Russell, I will go and check to see if the

In message , Ian Cockshull writes

Dear All

The suggestion by Russell to use a 60/80 tooth gear pair rather than follow the thread chart suggestion of 45/60 has worked a treat - a bit of a tight squeeze to get the 80t on the idler pin and avoid hitting things it shouldn't, but all is well.

Many thanks to all for their suggestions and offers of help.