tumbler reverse

[savarin]

I'm looking into making a tumbler reverse for my 9x20.
I'm sort of following the 9x20 LATHE TOP MOUNT REEVERSE TUMBLER by
Jeremy Taylor.
I'm considering making the shaft for the reverse gear (45t in Jeremy's plans) to fit the 42t gear but making the position adjustable for a 45t when I can find one as I may need the 42 for threading at some time.

If I had some brass I would make a bush for the centre of the gear but I dont so would the cast iron gear running on a steel shaft (polished smooth) be ok?

I will also be using a chunk of 6mm steel instead of 3/8 aluminium plate because I have a lot of it and it looks as if there is sufficient clearance so the large steel plate bolted to the head of the lathe doesnt need cutting, fingers crossed.
Thanks

 

[November X-ray]

You would probably be better off making a bushing out of steel and carefully press fit it into the gear and make sure to lube it often instead of just using the gear casting directly on polished steel. Of course if you could find some bronze, that would be even better or you could do what I did and use a roller bearing.

Good Luck.

 

[Pacer]

Oil-lite bushings come in just about every size, one of them would be ideal. Or, you can even get plain bronze bushes.

I use oil-lites a lot.

Steel on steel wouldnt be the first choice - cast iron on steel is good, and of course, brass/bronze, thats why you see CI gears riding on a steel shaft - or with a brass bush.

 

[Bill Gruby]

For some unknown reason my computer is against me this morning. I can't import what I want.

SOOO ----- Google Tumbler Reverse on a 9X20 Lathe. You will find a PDF file there titled," Tricking Out the Asian 9X20 Lathe" In that file on page 11 I believe is the Tumbler Reverse I used on mine. It took only 2 or 3 houre to complete it. Super Simple.



"Billy G" )

 

[rammed]

Hope this works

http://www.akpilot.net/Tricking Out/Tricking Out.pdf

 

[Bill Gruby]

That's the one and it link is OK. Thank you.

"Billy G" )

 

[savarin]

For some unknown reason my computer is against me this morning. I can't import what I want.

SOOO ----- Google Tumbler Reverse on a 9X20 Lathe. You will find a PDF file there titled," Tricking Out the Asian 9X20 Lathe" In that file on page 11 I believe is the Tumbler Reverse I used on mine. It took only 2 or 3 houre to complete it. Super Simple.

Remember this, the size of the idler gear is up to you, all it does is reverse the drive gear at the spindle. It will not change any speeds.

"Billy G" )

I have seen that one but forgot all about it.
I thought that using the above the headstock handle would mean a longer lever thus allowing detant stops for forward, neutral and reverse further apart. I will measure this today to double check.
With regards to the size of the reverse gear not changing the speeds I just cant get my head around, I've seen it mentioned in a lot of places but cannot see why it wouldnt change the speeds.
If the spindle gear is 40T (what my lathe is) then the nylon gear (80T) is driven 1/2 a rev for every rev of the spindle gear.
If the reverse gear is 40T then it drives the nylon gear exactly the same per revolution, but, if the reverse gear is a different size then surely there is a discrepancy in the amount the nylon gear will turn per revolution of the spindle and this will affect how much all the other gears down the train turn.
Surely this would show as a difference between the revs of the spindle and the revs of the lead screw making a left hand threading operation slightly out of size.

 

[Bill Gruby]

You are correct,I worded the other post wrong. My apology for the misrepresentation. Don't know where my head was when I posted that. I will delete that from the other post before it messes someone else up. It should have read "The idler needs to be the same sizs as the driver gear." Mine is the same as the gear on the spindle.

"Billy G" )

 

[savarin]

You are correct,I worded the other post wrong. My apology for the misrepresentation. Don't know where my head was when I posted that. I will delete that from the other post before it messes someone else up. It should have read "The idler needs to be the same sizs as the driver gear." Mine is the same as the gear on the spindle.

"Billy G" )

Phew! thanks for that Bill it was doing my head in as virtually all the posts I've seen state it make no difference but I couldnt see why it wouldnt make a difference.
Now I just need to find a 40T spur gear.
Time for some amber nectar I believe, have a good one.

 

[swatson144]

Don't laugh but I made mine out of 3/8" plexiglass and it worked like a champ I recently removed it to make it out of steel. Steel will allow me to weld a better fixture for adjusting it but a pin and 3 holes worked well just not very techy.


here it is freshly removed from the machine


I turned down hardware store bushings to fit the gears and made steel posts to fit the bushings simple wheel collars to hold it together and a washer for clearance. No harm to the original parts and it can be returned to stock simply enough.


The needed cut away on the gear plate.


I modified the outline to make it easier to cut from metal. I have made a CAD drawing up and will likely let it loose after I finish mounting and testing. Work got in the way.

Steve