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cityhick

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#1
Crashed my Logan (powrkraft) lathe. Anyone here able to fix me up. I can get the gears through logan but they aren't cheap.
gears.jpg
 

Sleddog

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#2
What DP are they & how many teeth? If I don’t need to buy a cutter I could possibly help out.
Jack
 

cityhick

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#3
The dual gear is 16/32 toorh the single is 40 tooth. Excuse my ignorance but what is DP?
 

francist

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#4
Diametral Pitch

In addition to knowing the tooth count, one needs to know the diametral pitch of the gears so that they all mesh properly.

Edit: I "think" Logan gears are 16DP, at least that's what I see on a MrPete video where he cuts a new one. I don't own a Logan though, so cannot verify this firsthand.
 
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Sleddog

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The dual gear is 16/32 toorh the single is 40 tooth. Excuse my ignorance but what is DP?
No problem....tell me the outside diameter of each gear & approximent tooth depth. I can calculate from that information.
 

cityhick

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#6
40 tooth... 2.105 diameter x.108 tooth depth
32 tooth... 1.701 diameter x .108 tooth depth
16 tooth... .900 diameter x .108 tooth depth
 

cityhick

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#7
I can send the gears to you whoever can make them to copy also
 

RJSakowski

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#8
Also, you need to know the pressure angle.
 

Sleddog

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#9
The gears in your picture appeared to be 24 DP, of which I have several sizes in both 14 1/2 & 20 PA. With your information I believe they are 20 DP which I do not have cutters for.
Hopefully someone with the proper cutters will chime in.
BTW, out of curiosity, what does Logan want for the gears?
 

cityhick

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#10
$218 for the 32/16 and $108 for the 40
 

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#11
Check Boston gears and see if they have them. They will have an ID site you can look at for the DP. Or go to Mr Pete’s you tube site, watch the video on logan gears and I believe he will give a formula for figuring the DP. Watching the video will help in ordering from Boston or in looking on eBay for what you need.
 

Ray C

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#12
Without a doubt, those are 20DP. No idea what the pressure angle is. You'll need to know the PA if the new gears must work with others in the original set. Change gears like these are typically a special breed of animal because they are hub-less. How many gears are in your complete set?

I have only 1 cutter in 20DP and off the top of my head, don't know what PA or tooth range it is for. I make custom stuff like this all the time but in this case, I doubt you would want to absorb the cost of the cutters. In this case, you need 3 different cutters.

Ray
 

Ray C

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#14
Take a picture of a good gear in the set. It must be very clear and fill the whole frame without cutting-out any portion of the image. It needs to look something like this. High resolution is needed. Never mind all the circles drawn... I'll need to do that to your picture to determine the pressure angle. You must photograph one of the good gears in the set. If I can't get a perfectly good image, I won't be able to determine the PA.

If all gears are badly worn or if by some chance, it's not a standard 14.5 or 20 degree pressure angle (very unlikely) I won't be able to determine what type of cutter is needed. If I can figure out the PA, we can work something out.


GearCloseUp.jpg


Ray
 

cityhick

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#15
Here s pics of the good gears. I can also send the gears to you and we can go from there if that works.
gear 40.jpg
good gear 40.jpg
 

Ray C

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#16
Here s pics of the good gears. I can also send the gears to you and we can go from there if that works.
View attachment 268508 View attachment 268509
Check your Inbox for a PM with my email address. When downloading the pictures, they are very low resolution and pixilate badly after 1.5x magnification. You'll need to email them directly to me. THe basic quality is good. If possible just re-do them with the lens dead in-line with the axis of the bore so you cannot see any of the sides of the bore in the photo. BTW: I'm having a memorial day observation with family and friends today so, I won't be able to do much with this until later this evening.

Ray
 

cityhick

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#17
I understand. Im in no hurry. I appreciate your time and willingness to try to help
 

Ray C

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#18
I understand. Im in no hurry. I appreciate your time and willingness to try to help
Thanks... BTW, this is not some wild goose-chase. I've done this before. In days gone by, the techniques I'm using were done with optical comparators / magnifiers and calibrated circular cut-outs. Nowadays, we have the advantage of digital cameras.

Ray
 

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#19
What are the logan stock numbers for the gears? Are they out of the QCGB?
 

cityhick

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What are the logan stock numbers for the gears? Are they out of the QCGB?
Not sure of the stock numbers. I have a catalog at work. Yes they are out of the QCGB
 

cityhick

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#21
Tubalcain did a repair to the lathe that I have on one of the gears that I have that is bad. Shows all the information we have been trying to figure out.
 

Ray C

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#22
From the earlier info you have, we knew DP was 20. Based on you picture, my gut feeling was these were 14.5 PA. This was because of the rounded nature above the visible center-pitch line. 14.5's always look more rounded and 20's are flatter looking. Again, this was just a visual guess. My plan was to overlay 2 circles on the the photo, one pitch circle for a 20PA and another for 14.5PA. From there, two things can be viewed to make the determination. One is the amount of clearance in the root. Sometimes it's obvious just based on root clearance. The other is to draw tangent lines from the pitch circles then, overlay PA circles to see which circle best fits the upper curve of the tooth.

Water under the bridge since you found MrPete's information...

Let me know if you want to try to obtain 3 cutters of DP20, PA14.5 in size #3 (40 tooth), #4 (32 tooth) and #7 (16 tooth).

Send PM to discuss details.

Ray
 

cityhick

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#24
I put an offer in on the ebay listing for the 32/16 gear.
 

Happycamper

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#25
You might ask the seller if he also has the 40 tooth gear.
 

cityhick

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I ended up buying a 16 tooth gear and a 40 tooth gear from Boston gear. Both will need some machining to make work but I have 40 bucks into the two total. I'm going the route that Tubalcain did in his video for the 16/32 gear and the 40 tooth gear has a .375 center hole that I will need to size to fit the oillite bushing. I appreciate the feedback from you guys and I've learned a few things so far along the way. Thanks again.... I'll post up some pics of the new gears when I'm done.
 

cityhick

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#28
Here is a pic of the finished gears. Lathe is back together and everything is working...sort of. Im going to pull the gear box back off and check some things. Seems to be a tight spot and you can hear and see it slow down then speed back up. Not sure if I bent one of the shafts that the gears ride on just slightly or what.
 

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markba633csi

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#29
Nice job and you saved some bucks too!
mark
 
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#30
Here is a pic of the finished gears. Lathe is back together and everything is working...sort of. Im going to pull the gear box back off and check some things. Seems to be a tight spot and you can hear and see it slow down then speed back up. Not sure if I bent one of the shafts that the gears ride on just slightly or what.
You may have a gear not quite round when running , something may not have been set up to a tight tolerances. It might need rebushing and bored out . Not just drilled and or reamed to size.
 
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