Gear cutter help

[RobonthemoorParticipant @robonthemoor]

Hi John, we have been down this road before, the early Deckels FP1 mills was indeed 14.5 PA as one of these shafts was made further back in this post by a forum user. Speed"" slow as it will go, think about 150rpm, yes the fly cutter is indeed a 7.5 " x 1" round disc solid as a rock on a 4 MT, as I know nothing about gear cutting but thinking of purchasing a 20 degree just to see if it works.

Rob

[Ian S CParticipant @iansc]

I'd make the fly cutter half the diameter that you have, or less, and keep the same speed. For a similar size gear, my fly cutter is around 1 1/4" diameter. Ian S C

[John Stevenson 1Participant @johnstevenson1]

Still think the Yank was wrong.

Anyway to prove a point throw a sketch up of the shaft sizes and give me a week, few pressing concerns at the moment, and I'll run a 1 MOD hob down a lump of steel and send it to you.

[RobonthemoorParticipant @robonthemoor]

Ian hi,, I have an inch one I could use how will this make a difference? All this is new to me, do you have any problems fly cutting gears, I have 14 teeth to cut @ 82 mm deep, lot of cutting for one, as a gear cutter as 12 teeth or so lot more cutting action,

rob

[John Stevenson 1Participant @johnstevenson1]

There's your problem 82 mm deep on a 16mm shaft is going to cause problems.

Just joking mate, we all knew you meant 0.82

[RobonthemoorParticipant @robonthemoor]

Sorry I do this a lot, 0.82" 2 & a bit mm. Ok John shaft size is 16mm 14 teeth if you do that I can try it in the Deckel I'm not saying your wrong John, you have forgotten more about this type of work than I will ever know, I have a thought that you have been on the money all the time, as when I measure the angel ( best I can) 14.5 looks wrong to me, but with no experience!,, if I can use a gear cutter that will cut the profile I will be well happy. Maybe I should stick to clay shooting at least I can win some money on that.

rob

[John Stevenson 1Participant @johnstevenson1]

I packed in clay shooting.

Don't care how well you cook them they still taste like roof tiles………………

[IanTParticipant @iant]

I like my clays cooked 'medium rare' but I now know who to blame for all those lead pellets in them!

[Howard LewisParticipant @howardlewis46836]

Hi Fellas!

A while ago, I had to make a one off 1 Mod 15 tooth gear, but had only a 1.25 Mod cutter.

After completely messing up one blank, I reduced the depth of cut shown on the cutter by a factor of 1:1.25, and a useable gear resulted.

This is theoretically wrong, but it sufficed for that particular application.

So, if you can get a 14.5 PA cutter, even if it is 1.25 MOD, you MAY be able to bodge in a similar way.

"Where needs must" and all that!

Howard

[John Stevenson 1Participant @johnstevenson1]

There would be less error using a 20 degree PA cutter than the method advised by Howard above.

Long Short is the depth has to be correct or close or the tops of the mating gear can't fit in.

[RobonthemoorParticipant @robonthemoor]

Just rang and bought a number 7 mod 1 20PA should be here Wednesday / Thursday try it and see how I go.

rob

[Roy MParticipant @roym]

Back in the olden days when I was tasked with the job of repairing gears, usually urgently and with little information about the gear form, I would make a single point cutter but try and keep the diameter to a minimum.(more cuts per minute). Having established the tooth form on the shaft or wheel, standard cutters can be used to remove most of the material allowing the form tool to last longer and so reduce re-setting time after touching up. Maybe useful in the future!

Edited By Roy M on 03/02/2014 18:48:41

[jonathan heppelParticipant @jonathanheppel43280]

You could settle the PA story by measuring the rack- that's what I would do.

[RobonthemoorParticipant @robonthemoor]

Just put the fly cutter cutting tool in a 1" fly cutter. Been cutting now for 2hours works perfect. Lesson learned .

[Ian S CParticipant @iansc]

Answered by Roy M, but the reason goes beyond the number of cuts per minute, importantly it reduces the cutting speed, as you have found. Ian S C

[RobonthemoorParticipant @robonthemoor]

1 rev is 1 rev""" but it now cuts smaller chips rather than a long slither.

rob

[RobonthemoorParticipant @robonthemoor]

Hi" almost done now, the gear cutter did the job, 20pa mod1 No7 just didn't go full depth, as the gears are 14.5pa mod1 No7 but you guys found a way to solve the problem. Just putting a taper on the end for the handle, & I have the woodruff key to cut, that arrived today, & I will post a photo.

thanks to you all.

Rob

[RobonthemoorParticipant @robonthemoor]

All done now, works well, thanks again to you all.

Rob

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