KT 2HL ,Need gear for vertical head - Page 4

1. Originally Posted by thermite
As far as CL distance.. yes, we CAN get that by measurement - covered earlier in-thread.
I can be sore tedious because it is awkward. OTOH, it need not be to "tenths", nor probably any closer than +/- 30 thou.
There are only a limited number of possibles for a mating gear.
Simple enough to disprove. Do the math, and you'll quickly understand that the center distance has EVERYTHING to do with the Helix Angle. Then ask yourself how long you want that gear ( that you just paid for ) to last.

2. Diamond
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Simple enough to disprove. Do the math, and you'll quickly understand that the center distance has EVERYTHING to do with the Helix Angle. Then ask yourself how long you want that gear ( that you just paid for ) to last.
We are not INVENTING a gear that has not already existed, though. The reverse, actually.

One goals is to insure our new gear is NOT "different" from the missing OEM one.

We are only getting close enough to ID which one of the limited subset of all possible gears that K&T actually USED is to be duplicated.

Specs won't come off the field measurement.

For closest match to what had been there? Specs need to come off the K&T data.

Same as a guy comes in with "I need 20 3/16" inch tires for my 2005 Jaguar." Or 19 7/8".

No. Your cheap tape measure is f****d. You actually need 20".

But at least we know it isn't the 18" for the taller-sidewall sofa-pillow ride Van Den Plas nor the 22" gumbands for the 500 HP blower model "R".
Last edited by thermite; 08-21-2018 at 07:29 PM.

3. Hot Rolled
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Standard 2HL Vertical Head drive gear:
24 Teeth
Disc Dia. = 3.000”
Disc thickness = .196”
Gear OD = 3.219”
Gear thickness = .878”

Sorry for the delay J.O., getting power to the shop has consumed me the last few days. I tried pulling the driven gear and it didn’t want to come out. Maybe the OP can post the dimensions of his driven gear and we can compare notes in a couple more days.

Andy

4. Plastic
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## Gear

Thanks ,
Everyone thanks for all the help. No matter how many times I count I come up with 23 teeth on my head , see pic and it is 3" od , see pic in first post for that pic , Is this the same as Hobby Shop's head ? I would guess that it would need to be the same 23 teeth in the head , 40 taper machine , 40 taper head ?We are getting close. I have talked to one guy on line who is searching , believes he has drawing , that will state to be used with a head having 23 teeth , maybe KT drawings? Many thanks to all , what would I do without all of you ! Thanks Daniel

5. Either Andy or Unobtainium needs to have driven gear out of head so they can tell us related disc diameter - or maybe it can be measured while installed. Looking at Unobtainium's photo in post above - it will be immediately behind (and smaller than) the 23 teeth See exploded parts scan in an earlier post.

So 24 driving 23 = .958333:1

Early forties full line catalog says this for Standard High Speed ....at 1400 main spindle RPM, the head spindle turns 1460 ....on 1H / 2HL

Very close to that above ratio.....1400/1460 = .958904 : 1

We are getting there, but the need for the DRIVEN (in the head itself) disc diameter is paramount - essential for coming up with actual centerline distance

6. Originally Posted by johnoder
We are getting there, but the need for the DRIVEN (in the head itself) disc diameter is paramount - essential for coming up with actual centerline distance
John ( or Ramsay1 for that matter ) -

Strictly a curiosity question - Is the disc ( that theoretically signifies PD ) a matter of law to be observed? In other words, are they always present? And, are they always cut to the actual, working PD of the gear that it is installed upon? Or, are they cut to some other working dimension? ( backlash added, possibly? ) Was this something done by the assemblers at KT at the time? Do the discs ever get banged up, or murderfied, making them unreliable indicators? Just curious. If they really are that reliable, it would be a fairly impressive and admirable effort and practice by the people at KT, back then. Would that more would do the same these days.

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## Rpm

johnoder , Thanks
How right you are! see attach pic , for attach speed.

Thanks Daniel

8. Originally Posted by Zahnrad Kopf
John ( or Ramsay1 for that matter ) -

Strictly a curiosity question - Is the disc ( that theoretically signifies PD ) a matter of law to be observed? In other words, are they always present? And, are they always cut to the actual, working PD of the gear that it is installed upon? Or, are they cut to some other working dimension? ( backlash added, possibly? ) Was this something done by the assemblers at KT at the time? Do the discs ever get banged up, or murderfied, making them unreliable indicators? Just curious. If they really are that reliable, it would be a fairly impressive and admirable effort and practice by the people at KT, back then. Would that more would do the same these days.
Those discs are always present in units that require them to keep the center distance unless some trunk monkey has removed them to make installation and removal of the unit "easier"...Ramsay 1

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John ( or Ramsay1 for that matter ) -

Strictly a curiosity question - Is the disc ( that theoretically signifies PD ) a matter of law to be observed? In other words, are they always present?
No, they are not. At least a few heads did not need them - as already posted. Their spacing was fixed and it was very rigidly fixed.

And, are they always cut to the actual, working PD of the gear that it is installed upon? Or, are they cut to some other working dimension? ( backlash added, possibly? )
Backlash added "probably". The disc was never going to grow any larger. It might wear smaller, so why would one not?
Was this something done by the assemblers at KT at the time?
Almost certainly finished to a stock size, AND NOT hand-fitted. NB: That may have been AFTER attachment to the gear. I would. Takes any mounting variation out of the variables set.
Do the discs ever get banged up, or murderfied, making them unreliable indicators?
Certainly probable some got the odd ding. Filing or stoning it off would not affect the "rest of" the spacer", so not a show-stopper.
Just curious. If they really are that reliable, it would be a fairly impressive and admirable effort and practice by the people at KT, back then. Would that more would do the same these days.
Fair certain K&T did not originate the method, nor the implementation of it. The "theory" could have been as old as the helical gear itself - if not older. OTHER gear forms have pitch lines, too, and they are many and varied. Putting it into actual practice was practical and silly-cheap vs the cost of generating the gear itself, having it fail prematurely, or having it damage its host.

The K&T gearsets may, however, have been among the "heavier" of applications of it as far as transmitting actual power, not just to support a range of optional ratios for indexing, timing, calculation, pointing, or such.

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Thanks again , here is a pic from Ramsay 1 (Post 15 , 4th pic), with his gear out of his head , looks like I will have to take my head apart to get the gear out to measure it , I see a snap ring grove , would have to remove the snap ring from inside the head ? correct ? And there is some ring behind it , about the right diameter , or a bearing , etc ?
?? Pull the head apart ??

Thanks Daniel

11. Originally Posted by unobtainum gear
Thanks again , here is a pic from Ramsay 1 (Post 15 , 4th pic), with his gear out of his head , looks like I will have to take my head apart to get the gear out to measure it , I see a snap ring grove , would have to remove the snap ring from inside the head ? correct ? And there is some ring behind it , about the right diameter , or a bearing , etc ?
?? Pull the head apart ??

Thanks Daniel
Yes it is not that hard to remove.. Take the cover off and I think the snap ring must be removed from the gear so that it can be removed from the bearing to come out....It has been awhile since I removed it and reassembled the unit....Here are a few pics...As can be seen, I had a crack in the housing that I had to braze..This unit is for a 2h that is why I don't just send the measurements as they would not apply to your unit... Ramsay 1

I think it should be crystal clear to all now just exactly why the spacer discs are needed to insure proper gear tooth backlash... Nothing at all dowels this unit to the overarms, in other words it is completely independent of the cutter head...

12. Originally Posted by unobtainum gear
Thanks again , here is a pic from Ramsay 1 (Post 15 , 4th pic), with his gear out of his head , looks like I will have to take my head apart to get the gear out to measure it , I see a snap ring grove , would have to remove the snap ring from inside the head ? correct ? And there is some ring behind it , about the right diameter , or a bearing , etc ?
?? Pull the head apart ??

Thanks Daniel
Sir: Here is an exploded view of the drive unit for your 2hl assembly.. This should make it as clear as mud... Ramsay 1

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The driven gear on my vertical head has 23 teeth too.

14. Thumbnail is Mr. Buckingham's great hand written effort on every thing needed from starting with center distance and tooth counts to selecting form type cutters for milling a 14.5 degree PA helical pair

Higher resolution versions can be emailed if one cares to private message that address

From the book Manual of Gear Design Section Three Helical and Spiral Gears by Earle Buckingham

I have no idea at all if the K&T gears are 14.5 degree or not

15. ## Involute Cutters For Helical Gears

Colvin and Stanley Second Edition "Gear Cutting Practice" 1943...Ramsay 1

16. Titanium
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Referencing post #63- If the 24 tooth gear has a 3" diameter disc that tells me the gear pitch is 8DP Tranverse. Now the only question is what the helix angle is. My guess is it will be 30 degrees based on the addendum I calculated from the od mentioned in that posting. This would be a normal DP of about 9.26, and you're not going to cut that correctly with a space cutter.

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Originally Posted by Dan from Oakland
Referencing post #63- If the 24 tooth gear has a 3" diameter disc that tells me the gear pitch is 8DP Tranverse. Now the only question is what the helix angle is. My guess is it will be 30 degrees based on the addendum I calculated from the od mentioned in that posting. This would be a normal DP of about 9.26, and you're not going to cut that correctly with a space cutter.
So is this something you can do ? would you need the gear , or do you have enough info ? How much do you think it will cost \$\$
Thanks

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Originally Posted by unobtainum gear
So is this something you can do ? would you need the gear , or do you have enough info ? How much do you think it will cost \$\$
Thanks
Dan is one of the gear guys on the site and offered to make it a while ago.. I’m sure he wouldn’t have any issue making your missing gear or any other gear. Did you pull the driven gear and get the measurements off it?

19. do you have enough info ?

Dan will have
enough info when you get the disc mic diameter behind the 23 tooth gear

None of this is magical - it depends entirely on the math related to what is there

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Originally Posted by johnoder

Dan will have
enough info when you get the disc mic diameter behind the 23 tooth gear

None of this is magical - it depends entirely on the math related to what is there
This is what I get , very fine ground finish on disc

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