Goodway 1640 end gear details requested.

toadboy65 · Mar 21, 2018

I am getting to the end of repairing and setting up my damaged 1992 Goodway GW-1640. I still need to figure out the tooth count and gear arrangement on the external gears that rotate on a bracket to drive the quick change gearbox. I have most of the rotating bracket, and can fabricate that. It is the tooth count on the gears that mount on it that is the issue.
A clear photo of the arrangement or a scan of the parts or operation diagram would be immensely helpful.
T

Richard King · Mar 21, 2018

You could contact ACRA Machinery out in California as they used to be part of Goodway. Be sure to have the serial number handy.

greggv · Mar 21, 2018

I think a standard gear set to drive the quich change gearbox would be a 36 tooth on the spindle, driving a 120 tooth, driving a 72 tooth on the quich change. I think you change the 120 to 127 for metric threads. At least that's how it works on our Hwacheon.

toadboy65 · Mar 21, 2018

In this case, the spindle outputs to a 36 tooth gear, which drives a 60 tooth gear. then there is the broken bracket/missing gear(s). The quick change box has two gears on the same input shaft, a 49 and a 42.

toadboy65 · Mar 22, 2018

Well, I paid for a manual, and you are correct. 120 and 127.
So one less thing to worry about.
Now I just need to find some that I can afford.

toadboy65 · Mar 25, 2018

I ordered 120 and 127 tooth gears from Boston Gear via Amazon, and it appears that what I need are metric gears, with a module of 1.5.
An affordable source for metric gears seems elusive. The Boston ones were not cheap, either. Does anyone have any suggestions?

toadboy65 · Apr 1, 2018

So, to put it clearly, Does anyone have a reasonable source for a metric, 1.5 module duplex gear, 120/127 tooth?
I have to make the bracket, so I am unconcerned about spindle bore.
Apparently, they are in common use on many European and Asian lathes, but not easily discovered for sale. Ebay has a listing for one from an Emco maximat lathe, but no dimensions are even hinted at.
My free lathe is becoming quite frustrating.

partsproduction · Apr 1, 2018

As for cheap, is this a hobby lathe? I never think about maintenance costs for a machine I'm making a good living with.
I'd send an existing gear to someone like Zanradt with a note requesting recommendations for blank OD's from calculations those gear guys are very familiar with, then buy saw cuts of the material he suggests and make up blanks. Machine the blanks to save money.

That how I've done it using local gear houses.

My Victor's pick off gears are splined internally, which adds to the cost, but you'll be down a few thousand dollars I'm afraid.
The gears from Boston won't cost as much but if your originals are at all like the one's in my Victor they won't work without splined centers, so any way you look at it you are going to have to pay, or learn a complicated set of new skills and make them yourself. My Victors gears are all heat treated too, another layer of expense, though they'd run fine for a long time without that.
The Victor also has extra pick off gears for module and some threads I may never need, you could save a bundle by living without the capability to do a job you may never need to do anyway.

toadboy65 · Apr 2, 2018

Cheap is relative. I wrote "reasonable", which in this case means somewhat proportional to the cost of production. It appears that quite a few lathes use 127/120 gears, and some proportion of those are metric. So it is pretty likely that they are a mass produced item, available somewhere.
These gears do not need thickened hubs, or lightening holes, and only need to be about .50" thick. I have to make the spindle and mounting bracket, so I do not care about the bore size.
I do not appear to have a local gear house.
Luckily, it seems that this lathe needs only that one combo gear to accomplish the whole available range of metric and SAE threading, by engaging either the 120 or 127 gear at the headstock and quick change box, engaging one at the headstock and the other at the quick change box, or engaging both gears at the quick change box simultaneously.
I have considered making them, and may do so. I think the 127 would be a fairly complicated job.

partsproduction · Apr 2, 2018

I made a set of 100/127 gears for a rare little lathe, the good thing about transposing gears is that they don't have to be perfect for most of us 'mercans, beings as we don't use them continuously, and a little noise is more acceptable than the sound of thousands of dollars flushing. I bought blank cuts of ductile iron since the originals for that little lathe were cast iron. If you can borrow a 100 and a 127 gear to mount on one end of a shaft and attach the blank on the other end you can make a simple tooth dog to index, and buy the proper cutter off ebay.

toadboy65 · Apr 2, 2018

That is sort of the direction I am heading.
The other, shorter term option is to use the pile of oddball gears I have acquired crawling over piles of tools at the scrapyard.
The basic goal is to turn the quick change gears a certain number of times for each turn of the headstock gear. I can make a generic gear board and use some combination of scrap gears to achieve the desired rpm ratios. I have been playing with gear simulation software, and it should be possible to do, although changing ratios will be tedious. But that is not an ideal solution to the problem.
Going the other direction, I could switch the gears on the headstock and quick change box to something more accessible. It is odd that metric gears are still a rarity these days.

partsproduction · Apr 2, 2018

Doesn't the lathe have a data plate that tells you what gears the lathe came with originally?

toadboy65 · Apr 3, 2018

Yes, everything is on the lathe, except the 127/120 combo gear. That one combo gear, engaging the fixed gears in different ways, allows the full range of threading options.
The headstock output is a 28, it has a 60 bracketed to it. The 60 engages the missing 127/120, which meets a 49 and 42 on the quick change box. The 49 and 42 can be driven simultaneously by the two sides of the 127/120 combo gear.

partsproduction · Apr 3, 2018

It sounds like all you need is to find out the exact tooth form, find from that the correct cutter needed to cut it, and buy that gear cutter on ebay. Then borrow both a 100 and a 127 tooth gear to attach to the other end of a shaft, key both the sample gear and the gear shaped blank to opposite ends securely with a bearing block between (I used a square 5-C collet block in a Kurt vise set just tight enough to allow turning when the nut was loosened, tightening the nut for each cut) and make a tapered dog indexer that fits the original sample's tooth.
This dog should be spring loaded so you can pull it out to turn to the next tooth to be cut.
The remaining problem I ran into was chatter, it's a big disc and really needs extra support to keep it from "singing". Instead I set a close block behind the back side of the blank and a destaco clamp on the front of the blank so that when engaged it acted as a disc brake.

I really traded much time and effort to reproduce poor gears, but for it's rare use transposing inch to metric the end result in a thread is as good as gears costing thousands.
If you need to turn threads for a telescope tracking mount it may not be accurate enough for the government though.

greggv · Apr 3, 2018

Probably be easier to either buy the other gears that match your 120/127 gears, or buy a 120/127 gear from existing machinery that matches your gears. I know Hwacheon has a large stock of parts, I donno about their pricing.

partsproduction · Apr 3, 2018

The gears on the little lathe were 14 pitch and 14.5 PA, which apparently aren't available. 14 pitch is an old standard, normally I think they go from 12 to 16. In fact I couldn't even find American cutters, ended up with NOS eastern European cutters. The real mystery is that they came out of China.

toadboy65 · Apr 4, 2018

I ordered the two gears from American Metric. this will be the third company I have ordered them from, but I was very specific in my measurements. Hopefully, I will be able to pin them together and get running with a minimum of drama.

toadboy65 · Apr 5, 2018

The Ametric gears arrived, and fit properly. They are stamped "Italy".

xmprx · Aug 20, 2018

toadboy65 said:
The Ametric gears arrived, and fit properly. They are stamped "Italy".

Hey where did you get your manual from? I just purchased a 1640!and need to locate a manual for it. Any chance your copy is PDF?

Thanks.
Matt

Goodway 1640 end gear details requested.

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