2:1 Helical gears for Mastiff

[ozzie46]

 

  I'm having a great deal of difficulty finding a pair of 2:1 skew gears for my Mastiff build. The gears are .6250 overall dia for both of them 32 DP, 8 tooth on one with a bore of .3125.  hub is .4375 by .1875. Gear width is .1875 by .6250 dia. This is the crank gear.

 The oil pump/contact breaker shaft gear is 32 DP, 16 tooth. Hub dia is .4375 by .1562 width.  gear face is .1875 width by .6250 dia. Shaft bore is .250.

 L.C. Mason described them as "2-1 Rating Special Spiral Gears" and he got them from a company cxalled "Bond O" Euston Road" catalogue No C.185. I guess they are no longer in business.


 Any help would be greatly appreciated. Any advise on what to substitute would help also.
  The cost of having a pair specially made is prohibitive.

  Ron

[Jasonb]

Have a word with Hemmingway they sell the gears as part of the casting kit and may be able to supply on their own or say who they get them from

http://www.hemingwaykits.com/acatalog/The_Mastiff___L_C_Mason.html

[JimG]

Bonds actually closed down just over two years ago and they were still supplying their model engineering parts up till then.   You might have some luck following the lead on this web page.

http://modelengineeringwebsite.com/Bonds_OEuston_Road.html

Jim.

[IanR]

Try HPC, Chesterfield or Muffett, Tunbridge Wells (I think) or use ordinary spur gears.

[Jasonb]

Ian they are crossed helical gears so spurs won't do and Ozzie is in America so better off trying Boston Gear than a UK supplier.

Ozzie are your sizes right as you say both the 8T and 16T are the same overall dia??

[JimG]

Try HPC, Chesterfield or Muffett, Tunbridge Wells (I think) or use ordinary spur gears.

HPC's smallest size in 32DP is 9T.  Muffett don't show any details of helical gearing - possibly bespoke. 

Jim.

[ozzie46]

Thanks Jason, Sent an e-mail to Hemingway. Yes the sizes are correct.

  Check out this site. It explains it better than I can.

http://modelenginenews.org/ed.2003.12.html#t7
 

  Thanks for the reply Jim sent an e-mail there also.

 
  Thanks Ian, Jason's right they are crossed Helical gears.

  Jim I already tried HPC. will try the others. Thanks
 

[Jasonb]

Ah yes, different angles on the two gears in which case very unlikely tobe off the shelf from the mainstream gear suppliers.

J

[Alankiff]

Hi,
I'm the bloke who bought everything that was left at Bonds when it shut!
Following your post I've dug through the stock room, which is full of gears of all cuts, pitches and materials.

Unfortunately I can't find any of these anywhere.

Bonds part number c185 would indeed have been the item you are looking for. The original part number was 5/84.  I have found reference to the gear set in a 1964 Bonds catalogue but it doesn't appear in anything past 1980.

I also have a large number of  Bonds production drawings.  They produced their own gears until about 1975 when they moved from London to Midhurst and outsourced production. Since I don't have the drawings, I cannot even get a set of these cut (one off would be quite expensive but can be done). 

What I can confirm is:
2:1 ratio.
Steel
Both gears have .562 pitch diameter
32DP
1/4 " bore
16 tooth cut 27º
8 tooth cut 63º


I suspect you need to contact Hemmingway who may have stock or may at least have the production drawings.

I Have loads of other 32dp spiral cuts but as the PCDs are all different you would have to make huge design modifications to get them to fit.

Best of luck sourcing a suitable alternative.

Al

[MuellerNick]

How much is such a set of skew gears?
I think I could cut them. But just a single set for $10 would be a total loss for me.


And I'd have to buy an imperial reamer. OMG! 


Nick

[steamer]

Ron,

Check your email...

Dave

[ozzie46]

  Thanks for checking Al. I do have an e-mail sent to Hemmingway but as its a weekend I haven't heard back from them.  Received your e-mail and replied before I read the new posts here.  I was able to figure out the 63 and 27 degrees with help from Marv Klotz's helixcf.exe program. Thanks Marv.

 Thanks for the thought Nick. I understand. A one off is quite job. As far as the bore if it was under .250 I could drill and ream it. 

   Dave, were you referring to Als' e-mail or did you send one?. If so didn't get it.


 Thank again guys.

 Ron
 
   

[cfellows]

I made a fixture for cutting true helical gears on my lathe.  Attached is a document I put together about it.

Here's videos of me making the gears and the finished gears...

<a href="https://www.youtube.com/watch?v=oSeMX9SZXXY" target="_blank">http://www.youtube.com/watch?v=oSeMX9SZXXY</a>

<a href="https://www.youtube.com/watch?v=zLZo0ggLoHI" target="_blank">http://www.youtube.com/watch?v=zLZo0ggLoHI</a>

<a href="https://www.youtube.com/watch?v=kAG808sAQ90" target="_blank">http://www.youtube.com/watch?v=kAG808sAQ90</a>

Chuck

[pgp001]

Hi Chuck

That looks to be a very interesting set up, did you say you had a document attached, I can only see the videos.
I would be very keen to see how you have done that.

Phil

[John S]

If you have a 1/32" end mill, a copy of Gearotic and a CNC mill it's a doddle. 



Took al of 5 minutes to do this using Al's information