Making gear cutters and gears

[HuubParticipant @huub]

For some years, I make my own gear cutters and gears on the lathe and the mill using the "button method". I made a video that covers all aspects of how I do this. Maybe it is help full.

Making gear cutters and gears

[HuubParticipant @huub]

A video about making gear cutters and gears

[Bill Davies 2Participant @billdavies2]

Huub, many thanks for linking your video – very detailed. And also for linking the spreadsheet for the button calculations.

Bill

[Alex DU PRE 1Participant @alexdupre1]

Huub, thanks from me also for the video and spreadsheet.

I have a question – are the button tool calc tables on p114 of Ivan Law's book correct (Gears and Gear Cutting book)? Ivan's tables do not agree with the results of Huub's spreadsheet or my own calculations from playing with CAD. My calcs agree with Huub's! Ivan's tables give button diameters/separations about 50% bigger. Ivan's tables also don't appear to match the results I would expect using his figure on p113.

To get from Ivan's figures to the values you want, you have to divide his figs by the diametral pitch of the gear required. If using Module gears rather than DP, 25.4/MOD = the DP value. e.g. 0.75 MOD = 33.87 DP.

I'd be very grateful if anyone can confirm, or otherwise, the accuracy of Ivan's tables!

Thank you!

[Martin ConnellyParticipant @martinconnelly55370]

The recent thread on making change wheels Thread 184394 contains a link to GearDXF. If you have a suitable CAD program you could use this to cross check a couple of button based tools from both sources against the required thread form to see what matches best.

Martin C

[HuubParticipant @huub]

Posted by Alex du Pre on 03/01/2023 08:43:08:

Huub, thanks from me also for the video and spreadsheet.

I have a question – are the button tool calc tables on p114 of Ivan Law's book correct (Gears and Gear Cutting book)? Ivan's tables do not agree with the results of Huub's spreadsheet or my own calculations from playing with CAD. My calcs agree with Huub's! Ivan's tables give button diameters/separations about 50% bigger. Ivan's tables also don't appear to match the results I would expect using his figure on p113.

To get from Ivan's figures to the values you want, you have to divide his figs by the diametral pitch of the gear required. If using Module gears rather than DP, 25.4/MOD = the DP value. e.g. 0.75 MOD = 33.87 DP.

I'd be very grateful if anyone can confirm, or otherwise, the accuracy of Ivan's tables!

Thank you!

My book of Ivan Law is the reprinted version of 2013.

On page 107 if have made a note for the bevel gear calculation to use cos not sin

On page 113 if have made a calculation note: Button Diameter = sin (pressure angle) x PDM (Pich Diameter in mm)

The table on page 114 is made for 1 DP gears 20°. Divide the value in the table by de DP of the gear to cut.

According to this table, a T17 20DP 20° gear would need a button diameter of 0.39" and a button separation of 0.435".
According to the spreadsheet, you need a button diameter of 0.207" and a button separation of 0.341"

I can confirm there is a difference in the results of the spreadsheet and the table in the book.

I will check the results using the formula's of MikesWorkShop and will report it later this day.

[HuubParticipant @huub]

I have checked the results using the formula's of MikesWorkshop. I find exactly the same results as in his table so I probably used, at least part of, his formula's.

The 30° table in the book of Ivan Law is OK.

[Alex DU PRE 1Participant @alexdupre1]

Huub, thank you so much for checking and confirming my suspicions that the 20 degree table on page 114 of Ivan’s book appears incorrect. Interesting that the 30 deg table is correct, I wonder how the error crept in.

I made some 0.75 MOD gears about 15 years ago, using button tools that I assume were based on the 20 degree table (can’t quite remember). They did seem to work ok but maybe because I machined a bit of extra clearance for good luck. I made a Eureka tool at the time which worked ok but was slightly out of tolerance; I am going to remake its main spindle part.

I am looking to make some 0.6 MOD button cutters. The button sizes are really tiny for the gears with few teeth, so I may end up making the gears with 25 or more teeth and buying the smaller ones.

Thank you again.

[Alex DU PRE 1Participant @alexdupre1]

Posted by Martin Connelly on 03/01/2023 09:21:16:

The recent thread on making change wheels Thread 184394 contains a link to GearDXF. If you have a suitable CAD program you could use this to cross check a couple of button based tools from both sources against the required thread form to see what matches best.

Martin C

Thank you for the link Martin, much appreciated. I’ll check it out.

[John HaineParticipant @johnhaine32865]

Though I seem to recall that GearDXF makes proper involutes rather than circular arcs so it may give small differences anyway.

[Roderick JenkinsParticipant @roderickjenkins93242]

I have this copy of a page from ME pinned to my copy of the book

Rod

[HuubParticipant @huub]

Posted by Alex du Pre on 03/01/2023 17:10:41:

Huub, thank you so much for checking and confirming my suspicions that the 20 degree table on page 114 of Ivan’s book appears incorrect. Interesting that the 30 deg table is correct, I wonder how the error crept in.

I made some 0.75 MOD gears about 15 years ago, using button tools that I assume were based on the 20 degree table (can’t quite remember). They did seem to work ok but maybe because I machined a bit of extra clearance for good luck. I made a Eureka tool at the time which worked ok but was slightly out of tolerance; I am going to remake its main spindle part.

I am looking to make some 0.6 MOD button cutters. The button sizes are really tiny for the gears with few teeth, so I may end up making the gears with 25 or more teeth and buying the smaller ones.

Thank you again.

A T15 M0.6 gear cutter has a 0.65 mm tip. That requires some precision but I think making a fly cutter using the mill and a vice or CNC lathe is still doable.

To compensate for the low rigidity of my mill, I cut the gears 0.1 mm deeper than required.

A rotary table can also be used for making a fly cutter. Rotating the cutter 180° to mill the actual cutting edges is a bit more accurate then using the vice.
I am currently working on a procedure to mill the end mill style gear cutter using the rotary table.

[GreensandsParticipant @greensands]

I seem to remember seeing one of Clickspring's masterly videos on turning up an involute gear cutting tool without the use of button tools and from what I could see he finished it to size by eye using fine emery cloth. Perhaps somebody could elaborate on this.

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