Gear Cutters vs Gear Hob

[ironman]

I am thinking of buying either a set if Involute gear cutters or a gear hob in the 48DP and 14.5 or 20 degree PA range.

I am thinking the individual cutters would be best because they would not need sharpening as quick as using the hob. Is this a good choice?

I have found RDG, UK has cutters with 48DP, 14.5 PA with 1" bore and the M2 Stub Arbor.

Maxwell Tools, India has 48DP, 20 PA, 3/4" bore and M2 Arbor.

CTC Tools, China has same as RDG.

RDG Tools in UK are cheaper in price not including shipping. Not sure of shipping from UK to Texas.

Any recommendations or advice from the more experienced to help me decide? Thanks guys.

Ray

 

[Lakc]

A commercial hob will be for a hobbing machine, so unless you have one of them your not likely going to purchase a useable item.
A lot of it depends on how many gears you feel like cutting.
Homemade hobs dont have any lead, cut all tooth ranges, and once you learn how to make them, sharpening them isnt a hard job.

 

[mklotz]

Travers sells cutters...

http://www.travers.com/skulist.asp?RequestData=CA_Search&navPath=All+Products%2F%2F%2F%2FUserSearch1%3Dgear+cutter&q=block+id+64074+and+class+level3+id+30188&minPrice=$29.84

I've never bought from them so I can't praise or condemn them.

 

[steamer]

A commercial hob will be for a hobbing machine, so unless you have one of them your not likely going to purchase a useable item.
A lot of it depends on how many gears you feel like cutting.
Homemade hobs dont have any lead, cut all tooth ranges, and once you learn how to make them, sharpening them isnt a hard job.

IF you only have a mill, +1 for cutters instead of hobs...and buy what you need....

Dave

 

[kcmillin]

I purchased two 48dp cutters from Travers. After my purchase I was sent a coupon for 20% off my next purchase. So I bought the rest of the set. I cant say this will be your experience but I was very pleased.

So far I have only used them a few times, but I am sure glad to have them. I like to do a lot of my own design work and having a full set gives me a lot of freedom when designing. But if you have a specific project in mind, only buy what you need.

Kel

 

[ironman]

Thanks guys for your replies. I have been single pointing my gears for a long time after watching how to make them and gear hobs on youtube from "Hobbynut" Shorty Leatherwood. I have been using his gearcodeit program for figuring gears and producing my G-code for making them for quite a few years now.

I haven't tried to make a hob yet. May try that before buying cutters.

Thanks again.

Ray

 

[John S]

Commercial hobs are different to the 'hobs' that Shorty shows on his You tube video's.

If you haven't seen them they are worth watching, I really rate this guy.

Commercial hobs have a helical tooth form and unless you have some way of driving them in mesh with the blank they will not work.

Shorty's 'hobs' are not actually hobs but stacked rack cutters with angled sides and instead of generating a true involute like the correct hobs do his cuts a series of flats on each tooth.

Not geometrically correct but satisfactory for home shop use.

John S.

 

[ironman]

Thanks John for the info. For my use, his type hob will probably work. He uses W-1 drill rod. All I have is O-1 drill rod. That will probably be OK for me.

I will use aluminum for my gears. They will be for a gearbox to use on one of my RC Tugboats.

Ray

 

[John S]

Ray, if you are using O1 for the hob and only cutting alloy gears then harden out and just grind the front cutting face, do not temper them, the heat from the grinding is enough to temper the very fine teeth and give you a far better cut.

John S.

 

[tel]

Yeah, I'm in favour of cutters over hobs as well. Most of mine come from RDG and they are of good quality for the price tho if I was cutting gears all day, every day, I might want something a bit better.

Just one thing with getting them from RDG - do it direct from their Web site rather than through eBay , as what you will save in the initial price difference, + not having to pay the 20% VAT + (after your first purchase) the 5% 'Customer Loyalty discount' will well and truly pay the postage and put a bit of change back in your pocket.

 

[ironman]

More good usable information. Thanks all.

Ray

 

[gmac]

Ray;
Before you give up on the hobbing concept you may want to review this gentleman's work - I can spend time on his website just admiring the quality and style of his machining!!!

http://metallmodellbau.de/GEAR-CUTTING.php

http://metallmodellbau.de/ lots of tooling projects and ideas here

It does translate to english - poorly - but for the most part the photo's speak volumes.

Garry

 

[ironman]

Thanks Gary,

Lots of good pictures. I am sure the information within was very informative.

Ray

 

[///]

...
http://metallmodellbau.de/GEAR-CUTTING.php
...
Garry

Mate that is an awesome page, cheers Thm:

 

[kasiktools]

Ironman : We are the company from Czech Republic. We produce exactly this tools. You can see at our website and find more informations - www.kasiktools.eu

 

[gus]

I bought from CTC. Module 0.8 and 1.0 which for now cover gear cutting for small 4 stroke IC engines. Timing gears for Webster and Rupnow engines were all DIY.

Currently there are about 6 HMEM Folks cutting DIY gears and all getting to be very competent.
Three of us went on to cut mitre gears too.

There is nothing shy about half having 1/2 tooth which part of the learning curve. Gus has 1/2 dozen such paperweights.