By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by Forum House Ad Zone

Gear cutting

All Topics | Latest Posts

Search for:  in Thread Title in  
Ron Todd21/10/2013 18:07:36
1 forum posts

I am building a 2" ploughing engine the drawing calls for 11 teeth 8Dp the nearest cutter is number one 12DP would they run together

JasonB21/10/2013 19:02:12
avatar
25215 forum posts
3105 photos
1 articles

This is one of the problems with Haining specifying 8DP for all the gears. If you want to build a truer engine then you need to use 7, 8 and 9DP geras, the smaller teeth being on the crankshaft, largest on the final drive. This also has the advantage of putting the shafts in the correct locations.

Hopefully Jo will see this and comment, she is currently redrawing the BB1 to give a better representation than Haining did, if not she has started a thread on MEM forum.

Edited By JasonB on 21/10/2013 19:02:46

Jo21/10/2013 19:22:47
198 forum posts

Thanks Jason,

Hanning in his designs made maximum use of his set of 8DP gear cutters that he had no doubt invested a lot of money in. But on the full sized engines you find that each of the shafts have a different DP. On a 2" model this will normally be 9DP, 8DP and 7DP. The result of this 'bodge' to use the same DP gear cutter is to change the centre lines of all the shafts and be warned they do not necessarily move at right angles to each other. So be aware that correcting the number of teeth to make a gear chain that looks much like the original is not an easy task, you will need to change the 2nd shaft location and assuming it is a Fowler the 3rd shaft location. Having said that having all the gears of the same DP is instantaneously recognisable to any rivet counter.

You cannot run a 12DP gear with a 8DP gear the profile is totally wrong. Also a 11 tooth gear cannot be cut with a standard gear cutter: the minimum number of teeth using a standard gear cutter is 12 teeth . You might want to look to buy a commercially hobbed 11 tooth gear once you have worked out which DP you want.

Which engine are you looking to build?

Jo

P.S. My own BB1 design is only out by one tooth on one gear from the original Fowler BB1 gear chain wink 2 I am looking for somewhere to post my full BB1 build (where I retain full rights to the copyright of the posts ) if anyone can suggest a suitable location

John Stevenson21/10/2013 20:03:39
avatar
5068 forum posts
3 photos

If they were hobbed Jo you could have the right number of teeth and the correct centres.

All different numbers of teeth but all on the same sized blanks and you can interchange these as you like.

John S.

All Topics | Latest Posts

Please login to post a reply.

Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

Sign up to our Newsletter

Sign up to our newsletter and get a free digital issue.

You can unsubscribe at anytime. View our privacy policy at www.mortons.co.uk/privacy

Latest Forum Posts
Support Our Partners
cowells
Sarik
MERIDIENNE EXHIBITIONS LTD
Subscription Offer

Latest "For Sale" Ads
Latest "Wanted" Ads
Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.

Click THIS LINK for full contact details.

For subscription issues please see THIS LINK.

Digital Back Issues

Social Media online

'Like' us on Facebook
Follow us on Facebook

Follow us on Twitter
 Twitter Logo

Pin us on Pinterest

 

Donate

donate