Search found 129 matches

by KellyJones
Thu Sep 15, 2016 10:00 pm
Forum: General Discussion
Topic: MSC-Enco Transition - Quality-service-price-etc.
Replies: 9
Views: 1879

Re: MSC-Enco Transition - Quality-service-price-etc.

I dunno. Had to replace my 6 inch dial calipers recently. My old ones were from Enco and cost about $36. Not the highest quality, but felt good to use and serviceable for my needs. Dropped them ( sad story) and had to replace them. The new MSC calipers, for approximately the same money, feel cheap a...
by KellyJones
Tue May 19, 2015 2:27 pm
Forum: General Discussion
Topic: Basic Gear Information
Replies: 21
Views: 2730

Re: Basic Gear Information

Well, you've got me.

As a gear designer I have never heard that one before. Since I don't actually run the hobbing machines, it might be true, but in 30 years I've never heard or read that.

Next time I'm in the shop I'll ask the machinists.

thanks
by KellyJones
Tue May 19, 2015 8:21 am
Forum: General Discussion
Topic: Basic Gear Information
Replies: 21
Views: 2730

Re: Basic Gear Information

Good points. The lead of the hob is accounted for in the pitch diameter of the hob, the width of the hob teeth, and the timing gears between the hob and the work. By the time the next set of hob teeth engage the work piece, the work has rotated tot he correct position to accept them. In other words,...
by KellyJones
Mon May 18, 2015 9:27 pm
Forum: General Discussion
Topic: Basic Gear Information
Replies: 21
Views: 2730

Re: Basic Gear Information

We have discussed how many gears are machined using a generating method using either a hob or shaper, and a brief overview of how the generating process produces the desired tooth shape. So let's see if we can bring this subject a little closer to the HSM. First, we are going to get a little theoret...
by KellyJones
Mon May 18, 2015 12:51 pm
Forum: General Discussion
Topic: Basic Gear Information
Replies: 21
Views: 2730

Re: Basic Gear Information

Mauro Sorry - I saw your login name and misread it - before I had my morning coffee. Yes, I think you have it right about the hob moving to cut the face width. Could an arrangement such as you describe work for cutting helical gears? I have never seen one and my first reaction is that the hob (havin...
by KellyJones
Mon May 18, 2015 8:11 am
Forum: General Discussion
Topic: Basic Gear Information
Replies: 21
Views: 2730

Re: Basic Gear Information

Good question Tom. First a word of clarification. The hob only rotates, it does not move axially to generate the teeth. The hob moves along the axis of the work piece to enable cutting the entire face width of the work, and it moves radially with respect to the work to change the depth of the tooth ...
by KellyJones
Sun May 17, 2015 3:45 pm
Forum: General Discussion
Topic: Basic Gear Information
Replies: 21
Views: 2730

Re: Basic Gear Information

Thanks for the comments folks. Tom - I couldn't ask for a better straight man. If I understand your question correctly, that is today's topic. We've talked about the involute, and the basic rack, but how does that allow us to cut parts (on an industrial scale)? Good question. Hobbing is an example o...
by KellyJones
Fri May 15, 2015 10:17 pm
Forum: General Discussion
Topic: Basic Gear Information
Replies: 21
Views: 2730

Re: Basic Gear Information

So what does an involute curve look like? It's not a circular arc, or an ellipsoid, or anything else. Perhaps you've hear this one before. Take a can and wrap a string around it. Keeping the string taut, unwind the string from the can. The path traced by the end of the string is an involute curve. h...
by KellyJones
Fri May 15, 2015 9:56 pm
Forum: General Discussion
Topic: Basic Gear Information
Replies: 21
Views: 2730

Re: Basic Gear Information

Thanks for the words of encouragement. Last time we said we would discuss the involute and how it's generated. We're going to get a little theoretical here, so bear with me. If we have two arbitrary cams, mounted on different centers, and use one to drive the other, the two cams will (hopefully) con...
by KellyJones
Wed May 13, 2015 9:48 pm
Forum: General Discussion
Topic: Basic Gear Information
Replies: 21
Views: 2730

Re: Basic Gear Information

One of the problems facing HSMs is, given a gear sitting on a bench, how do I order a replacement (or make a replacement)? One of the first things you need to figure out is the diametral pitch. If you have removed the gear from an operating machine, it's pretty simple. The center distance is equal t...
by KellyJones
Wed May 13, 2015 9:28 pm
Forum: General Discussion
Topic: Basic Gear Information
Replies: 21
Views: 2730

Basic Gear Information

I get the impression that many folks on this forum find gears and splines a bit of a mystery. I am a gear designer by trade and weekend (relative newbie) home shop machinist. I thought I might be able to repay the many machinists on this forum for their sage advice and wisdom by posting small, diges...
by KellyJones
Mon Mar 23, 2015 9:22 pm
Forum: General Discussion
Topic: Metal working clubs
Replies: 1
Views: 565

Metal working clubs

Are there any metal working clubs in the Seattle or Everttt, Washington area?