I need a small rotary table to undercut some transmission gears. biggest gear I have is about 3" in diameter. Will a 4" table be suffice? What are your opinions on the cheap ebay ones for $80-$200? I dont have the money for a more expensive one. I need to finish a few jobs then I will reinvest in a better one.
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EBAY rotary table reviews... your thoughts?
- Thread starter R1Rider
- Start date
- Replies 26
- Views 6,862
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A 4” Chinese rotary!? I would say that might not even have enough usefulness to weight down a stack of papers.
I subscribe to the mindset of buy once by buying quality. If you keep an eye on eBay you can find a quality 8-10” Japanese plate for $2-300.
Also, if you talking about a 4” chuck/rotary, I think you’ll find that a 4” chuck might leave you wanting a little more holding power
I subscribe to the mindset of buy once by buying quality. If you keep an eye on eBay you can find a quality 8-10” Japanese plate for $2-300.
Also, if you talking about a 4” chuck/rotary, I think you’ll find that a 4” chuck might leave you wanting a little more holding power
Limy Sami
Diamond
- Joined
- Jan 7, 2007
- Location
- Norfolk, UK
Some thoughts, .....may be a waste of time, might save you wasting your $$
Are those transmission gears hardened?
What machine is the rotab going on?
Are those transmission gears hardened?
What machine is the rotab going on?
plastikdreams
Diamond
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- May 31, 2011
- Location
- upstate nj
Radioactivity...
If you just need to spin a part on the table, a lazy Susan will work. If you need to machine a gear, I would not waste your money
HAHAHA true
Yes, they are hardened.
Why is it a waste of time/money? Can I get some reasons?
its going on a JET JMD-18.
Errr...
This is a forum of mostly professional machinists. Guys that have done this sort of thing day in and day out. If you’re just trying to have fun in your garage than buy what you like and don’t ask opinions. If you are looking for genuine advice, than don’t buy it.
If you are first and foremost trying to modify gears, than I would suggest giving that money toward a shop that can properly machine these. Especially is they will see any sort of power and/or RPM.
Might I ask why you are buying Far East junk when you are in the land (Illinois) of quality used machines??.
Tyrone Shoelaces
Diamond
- Joined
- Apr 19, 2006
- Location
- Manchester, England
If it is a rotary table and not a chuck you need room to mount your clamps to hold the gear. A 4" table wouldn't be anywhere near big enough in my opinion.
Regards Tyrone.
Regards Tyrone.
Limy Sami
Diamond
- Joined
- Jan 7, 2007
- Location
- Norfolk, UK
You are not going to cut hardened steel transmission gears with almost any milling cutter, and most definitely not in that machine, for it is nowhere rigid enough.
If you must go ahead on that machine with a rotab - (you will need a much bigger one though - rigidity is everything!!) there is a possibility of grinding the gears, but it's a very dodgy operation for an experienced machinist, so one I am not prepared to comment any further on.
People are doing it every day...... guys are repairing these gears at home crudely in a drill press and with dremel tools.
I'll figure it out on my own.
Peter Colman
Stainless
- Joined
- Sep 22, 2004
- Location
- Rugeley UK
You have had a lot of negative responses but let's be realistic, you can't afford a top quality rotab so it's this or nothing.
I prefer to cut gears using a dividing head with the blank on a mandrel and a tailstock so getting greater rigidity but if you are going down the rotab route I would say you will get away with what you have in mind.
Milled gears will never be super precise however good the dividing is, I assume you are not going to be grinding them.
Without getting too technical, however rough the worm and gear in the head are,they will give you your divisions with surprising accuracy. Take care with eliminating backlash, make sure that the centre bearing is not loose and lock up before each cut.
I prefer to cut gears using a dividing head with the blank on a mandrel and a tailstock so getting greater rigidity but if you are going down the rotab route I would say you will get away with what you have in mind.
Milled gears will never be super precise however good the dividing is, I assume you are not going to be grinding them.
Without getting too technical, however rough the worm and gear in the head are,they will give you your divisions with surprising accuracy. Take care with eliminating backlash, make sure that the centre bearing is not loose and lock up before each cut.
That’s why I genuinely recommended other forums. Guys here are only going to give safe, and sound advice.
Before you undercut gears, please understand the dangers of creating stress risers. I would hate to see a gear come apart at 10000 rpm on your R1 going down the freeway. Good luck, and use some sense in whatever route you chose.
Limy Sami
Diamond
- Joined
- Jan 7, 2007
- Location
- Norfolk, UK
You came to a professional machinists forum for advice - which you have received, .....whether you take said advice is obviously up to you, .but please take care.
Spruewell
Hot Rolled
- Joined
- Sep 8, 2015
- Location
- Northern California
This is sounding more and more like wrong tools for the job. However you are asking this in a forum filled with people whose business it is to have the proper tools for the job, so the responses you are going to get are going to reflect “best practices”. What you are trying to set up is something that should be done on a lathe. Way quicker, more accurate and will produce far superior results to what you are trying to rig up. For the money you have spent on the equipment you have (unless it was given to you) you could have had a professional machine shop do the work right probably about 15 times over.
Spruewell
Hot Rolled
- Joined
- Sep 8, 2015
- Location
- Northern California
But for the sake of wanting to learn and expand your knowledge and capabilities. You could put a locating ring on the rotary table with a stud up middle and a plate to hold the gear down. Then you will need a good mandrel to mount a grinding wheel or cut-off wheel to that will fit into your collet (1/2” min.). Make sure you are wearing personal safety gear!
Good Luck! And be safe!
Good Luck! And be safe!
Bill D
Diamond
- Joined
- Apr 1, 2004
- Location
- Modesto, CA USA
You need several inches on each side of a gear for clamps to hold it down. For a 4" gear I would think 8" table or more. You can not hold it down well enough with one clamp in the center hole. If you try that it will spin a little and ruin the tooth relationship geometry. This is simple physics of leverage arms. Similar to the laws of physics that prove you can not pull a rope horizontal by pulling at both ends.
Bill
Bill
projectnut
Stainless
- Joined
- Mar 4, 2006
- Location
- Wisconsin
I agree with those that say don't waste your money. First off your going to need at least an 8" table to mount the gear and hold it with clamps. Secondly the Chinese tables are sloppy and difficult to rotate accurately to the proper degree settings. They are also made of poor quality materials that wear and crack easily. I think you'll be more than disappointed with what your getting for the money you spend.
When I was in a pinch a while ago I bought an 8" Palmgren rotary table. I bought it used for less than $75.00. It isn't the same quality as a Tryoke but far better than the stuff from China.
PALMGREN 328�3 Rotary Cross Slide Table, 8 In | eBay
For all I know they may be made in China today. I do know I certainly wouldn't pay a fraction of what they are asking today for a new one. I would much rather find used Tryoke, Moore, Bridgeport or other quality name brand before I would even consider something from China.
There are currently over a dozen 8" - 15" used rotary tables on craigslist's throughout the Illinois, Wisconsin, and Iowa. Here's one in East Dubuque:
Troyke & Palmgren Rotary tables & tapping head - tools - by owner - sale
It's a far better investment than anything you could buy from China.
When I was in a pinch a while ago I bought an 8" Palmgren rotary table. I bought it used for less than $75.00. It isn't the same quality as a Tryoke but far better than the stuff from China.
PALMGREN 328�3 Rotary Cross Slide Table, 8 In | eBay
For all I know they may be made in China today. I do know I certainly wouldn't pay a fraction of what they are asking today for a new one. I would much rather find used Tryoke, Moore, Bridgeport or other quality name brand before I would even consider something from China.
There are currently over a dozen 8" - 15" used rotary tables on craigslist's throughout the Illinois, Wisconsin, and Iowa. Here's one in East Dubuque:
Troyke & Palmgren Rotary tables & tapping head - tools - by owner - sale
It's a far better investment than anything you could buy from China.
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