Thread: Gear cutting with chinese cutters.

I don't know where my cutters come from - either China or India - but they are probably similar to yours.
At 16 DP you can probably cut in one pass rather than gash and then cut but the choice is yours and will depend on how rigid things are. I don't run flood coolant (not set up for it) but do put an occasional drop of oil on the cutter. As the smoke clears I tell myself that it was a good thing to do.
I do go over the cutting face with a diamond hone just in case some burrs are hanging around or an edge has build up.
Other than that, usual stuff applies (check for cutter run off clearance before cutting, make sure everything is tight and so on)

Michael

Hi RC,
I have some ctc ones, not sure if these are much better than the generic Chinese ones or not. I have found running them slow, around 80-90 fpm and with a feed around .0005" per tooth they last ok, mind you I have only cut CI and 1020 with them. Oh, and flood cool for sure. It's funny, I'm just about to set up to cut some gears myself, and had never noticed the numbering be the wrong way, but mine are the same, #8 is the 135- rack cutter.

Ew

For some oriental reason they number there cutters opposite to norm.

For 16Dp full depth in one pass will be fine with 4140.

If you have coolant use it,if not try to rig some constant feed up.

How are you mounting the cutter?

How are you supporting the work piece?

Thanks everyone....

Not sure how I am mounting the workpiece in the dividing head or the cutter yet, the job will be awhile away as I want to put a DRO on the mill before I start... But I may make a start on the blank tomorrow...

I have to make a new part for the 10EE for the telescoping cross slide screw..

This is what happens when you let coolant get into your apron, most of the apron gears looked in similar condition, lucky I got good second hand ones for replacements from the US....

20131206_075142.jpg

Originally Posted by .RC.

Thanks everyone....

Not sure how I am mounting the workpiece in the dividing head or the cutter yet, the job will be awhile away as I want to put a DRO on the mill before I start... But I may make a start on the blank tomorrow...

I have to make a new part for the 10EE for the telescoping cross slide screw..

This is what happens when you let coolant get into your apron, most of the apron gears looked in similar condition, lucky I got good second hand ones for replacements from the US....

20131206_075142.jpg

That looks nasty RC.
Where and how was coolant getting into the apron??
My understanding is they are a sealed unit...

Matt

Coolant shouldn't be getting in - below is a section from my manual of where the gear and shaft sit (gear + shaft coloured in purple)

apron (Large).jpg
There isn't an obvious place. The gear is not even visible when the cross slide is cranked all the way across, exposing the screw. If coolant gets into the apron proper (again, no obvious way if everything is where it should be) then the cross slide feed gear in the apron could pick up coolant and pass it onto the gear in question, but as oil floats on water the amount of coolant would need to be large - and the saddle oil pump feeds from the bottom of the apron so both ways (X & Z) would have had coolant introduced to them, as would gears, bearings and half nuts.
The only way that I can think of is if the SHCS that hold the apron onto the saddle were missing or not tight then coolant could possibly collect in the counterbores for them and funnel in but that's a lot of coolant being splashed in the wrong place.

I agree - nasty.

Michael

Just an update....

I got up early this morning and cut the gear that is made out of 4140...

The cutter did it no problems....

20140113_071254.jpg

Originally Posted by .RC.

Just an update....

I got up early this morning and cut the gear that is made out of 4140...

The cutter did it no problems....

20140113_071254.jpg

Congratulations. One step closer to the 10EE refurbishment and addition of capacity to the shop. Both a plus.

IME it's often years before you need to cut some gears, and then you need to do it fast, so having the ability is well worth it.

PDW

well this thread popped up just at the right time , i have 2 gears to cut very soon too . i was wondering weather to buy a set of ctc m0.5 cutters or just buy the 2 correct cutters that the plan calls for from elsewhere .
the plans call for 48DP 14.5 number 2 and 3 for the 2 gears i have to cut one is 72 tooth and the other 36 tooth =2 to 1 .now i know zip about cutting gears would it be ok to swap from the 48DP to the module 0.5 cutters and are the ctc ones ok , a set of 8 is cheaper than what i can find 2 of the others for .
sorry to butt in on your thread mate but its all related me thinks .

johno

My cutter came from withmybest2010 on eBay

If you can adjust the plans you might be able to use the Module cutters,if not you would have to stick with the DP cutters. If the plans call for a particular centre distance between the gears the Module gears will not be the same as DP. The standard size for 72 teeth is 1.625" and 36 teeth is .7916" with 48DP. The same tooth count in .5 Module will be 37mm and 19mm.( 1.456" and .748" ) The conversion of the DP od to metric is 41mm and 20.1mm.

ok thanks for that , may be easier to source the 48DP cutters rather than change to much . the plans are imperial and call for the teeth to be cut 45 thou deep on the 2 blanks of 1.542" (72T)and .792" (36T) diameter .

johno

Johno,
Can you post a picture of what you are trying to do? It may be that the centre distance can be adjusted enough to make using M0.5 cutters feasible (and we all like to see what others are up to as well). I have some M0.6 cutters that you could borrow but only have a no. 5 48DP.

Michael

i have hardly any of it built yet , it is the farm boy hit and miss model engine , the gears are for the valve timing there is not a lot of room for changing centres i am a bit worried that changing things may cause probs further into construction .i have decided to try and track down the 2 48DP cutters that i need and stick to the plans to the letter .
dont need to do the gears for a while yet at my current rate of progress so i have plenty of time to find some cutters
johno