Compact 5 change gears

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fourjc
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Compact 5 change gears

Post by fourjc »

Need help with change gears
I purchased this lathe 7 years ago It did not cone with change gears. I just finished designing 8 of the gears that I hope to print on a 3D printer. Looking at the Emco manual the gear selection for the pitch is confusing to me. They give you W 20 teeth (spindle) then Z1 72, Z2 40-20, L 25.
I guess I would need to post a picture of this unless someone knows this lathe. My problem is The 72 meshes with the 20, there is a secondary gear that meshes with 40 teeth. There is no mention of how many teeth on this one. The remaining 20 and 25 I have no problem with.
The gear selection above is for 10 TPI... My lead screw has 16 TPI. Any help would be appreciated.
jcfx
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Re: Compact 5 change gears

Post by jcfx »

Posting a picture would help, I'm not familiar with the Compact 5 but I am familiar with Emco machines since I own two of them ( V10P and V7 ).
My V7 required me to swap gears out so I'm familiar with the weird way they diagram out the change gears, I'm hoping that it's similar,
but your change gear banjo should be angle adjustable and should have a T slot that the gear axles connect to, on my V7 I had to slide
the gear axles and adjust the banjo angle till the gears meshed. There may also be bushings and gears that may have to be added or subtracted
in order for the gears to mesh.
Hope this helps.
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fourjc
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Re: Compact 5 change gears

Post by fourjc »

Thanks jcfxfor the reply...
2 pictures attached.
There are 2 gears in position Z1 but the chart only list's one. Am I missing something.
Attachments
compact 5 gear table.jpg
Emco gears.jpg
earlgo
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Re: Compact 5 change gears

Post by earlgo »

Here is the change gear page from the book "How To Run A Lathe" by the South Bend Lathe Co. It should at least let you know one method of calculating the proper change gears. Whether you have the right gears or not is in your hands.
From HTRAL book
From HTRAL book
Some change gear stacks that are used, for example on the Atlas, use a second gear just as a spacer to keep things aligned. Sometimes there is a plain spacer available.
Hope this helps steer you in a useful direction.
--earlgo
Before you do anything, you must do something else first. - Washington's principle.
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fourjc
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Re: Compact 5 change gears

Post by fourjc »

Thanks for the response "earlgo" but I cant see how the Atlas information can help me. I know all of the gears I need except for the sister gear in position Z1. I think I need someone who is familiar with the Compact 5.
If you look at the table for 10 TP,I position Z1 needs 72 Teeth, but it also has a sister gear that drives Z2. that is the one I need to know. The same problem exists for all thread pitches. I presume it might be 25 teeth but cant be sure.
spro
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Re: Compact 5 change gears

Post by spro »

I've been trying to figure this Compact 5 chart out. "W" is spindle and "H" is so important that they would have had to make the chart wider. I think "H" is toward the Headstock. So they abbreviated the gear number by the vertical " I " mark to the next gear. In this case it would be 20T.
maybe. The ratios seem off but 10 TPI is the fastest thread feed with the smallest Lead gear.
jcfx
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Re: Compact 5 change gears

Post by jcfx »

fourjc wrote: Tue Jan 16, 2018 9:46 am Thanks jcfxfor the reply...
2 pictures attached.
There are 2 gears in position Z1 but the chart only list's one. Am I missing something.
Looks like you doubled up gears on Z1 and you're missing a spacer, my Emco V10p and V7 manual
has a legend that says H is a spacer or bushing. The gear axles on Z1 and Z2 look reversed to me
does your banjo have a T slot milled in it ?

This is how I'm reading the chart for a 10 tpi gearing -
W - ( spindle ) 20 t*
Z1 - ( H = spacer) H spacer and 72 t gear
Z2 - 40 t gear and 20 t gear
L - 25 t gear and H ( H = spacer )
* t = tooth
You have to look at the columns for the gearing as a vertical flow chart,
So the mesh and assembly sequence is spindle ( 20 t ) with a spacer in front of
72 t gear which meshes the 20 t gear thats behind the 40 t gear that meshes with the
bottom 25 t gear with spacer behind that gear.
jcfx
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Re: Compact 5 change gears

Post by jcfx »

fwiw here is the page out of my V7 manual, I'm assuming that the letter designations would be the same
for all Emco machines.
Emco V7 change gear chart.jpg
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fourjc
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Re: Compact 5 change gears

Post by fourjc »

Thanks "spro" you comments put me on part of the right track...
W is the spindle with 20 teeth... and now I found the English version of the manual with the paragraph that mentions " Spacer H"
Now I understand the H but there is still a need for a second gear at position Z1.
If you look at the first pictures I posted, the big gear at Z1 is meshed with the spindle W while the smaller gear is driving Z2.
Attachments
Spacer  HHHH.jpg
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fourjc
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Re: Compact 5 change gears

Post by fourjc »

jcfx, Thanks again.. your chart looks more usable than mine if I ignore the upper gears and concentrate on the W, Z1, Z2, and L. The one problem however is that W is my spindle and the gear is integral to it.
jcfx
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Re: Compact 5 change gears

Post by jcfx »

My W is the tumbler gear assembly that gives me forward/neutral/reverse, and is driven by the spindel, the compact 5 doesn't
seem to have a tumbler assembly at least not that I can see in your picture. But I'm not sure if you can use the chart from my V7 lathe
it's meant for a imperial lead screw that's 16 threads per inch, not sure what the tpi is of your compact 5 lead screw is.

I still don't think you need a second gear in Position Z1, it's not called out in the diagram, as in my earlier post
there are spacers involved, and after looking at a video of your quadrant ( or banjo as I call it ) it has the ability to
move the gear axles to account for the different gear diameters .
Z1 72 t gear is driven by the spindle ( W ) which drives the 20 t gear which is behind the 40 t gear on Z2, the 40 t gear on Z2 drives
the Lead screw gear which is 25 t.
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fourjc
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Re: Compact 5 change gears

Post by fourjc »

Thanks "jcfx" your explanation got me to view the attached gear layout very differently. Using you logic, I now can look at the chart and make sense of it. I now feel confident enough to have the 8 gears that I designed 3D printed. Now if someone had dimensions on the quadrant arm that holds these gears it would save me some time.
Attachments
gears.png
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