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Vertical to Horizontal Mill conversion.

Use gear from Angle Grinder to get a horizontal mill.

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Skarven18/12/2011 19:08:03
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93 forum posts
11 photos
Hi,
I have no supply of all the standard pieces of steel and Al, square and round in different dimensions ..., so I have to cut most of the pieces from large pieces of steel and Al. I use a slitting saw in the mill for this, and it works great, but I often think that the work holding would be a lot easier if I had a horizontal mill shaft for the slitting saw. I have 3 angle grinders (why?) and I have been looking at the gearbox on them to make a Vertical to Horizontal conversion for my mill.
 
These angle grinders are cheap at about £20 on special offer, and if you let them idle at full rpm for a little when they start to smell burnt insulation, they will last a long time.
I have never had a gearbox on them fail, so they must be quite good.
 
My mill has a cylindrical quill 96mm diameter at the lower end, ISO 30 shaft, and it should not be to difficult to make an adapter for the quill and shaft.
 
Has anybody tried something similar to this!
 
I know there are commercial products out there, but they cost a lot, and most of the fun is of course the making of it.

Edited By Skarven on 18/12/2011 19:24:33

Nicholas Farr18/12/2011 21:51:53
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2549 forum posts
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Hi Skarven, I've thought of using an old burnt out 100mm angle grinder that I have had now for some time in exactly the same way, but alas have not yet had the time to make such an adapter and like yourself think that it should not be too difficult to achieve.
 
Regards Nick.
Ian P18/12/2011 22:04:24
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2452 forum posts
101 photos
I am pretty certain the gears will be up to the job but the weak point might be the bearings on the output spindle.
 
Ideally you want the saw to be solidly mounted with no play in the bearings. By design the the ballrace/s in an angle grinder are going to quite close together which will make any play in the baerings more noticeable.
 
Presumably the grinder input shaft is actually the motor armature spindle so if you ditch the motor you will have to engineer something to hold the gear.
 
Other than that the idea is sensible.
 
Ian
charlie murphy18/12/2011 23:06:02
6 forum posts
7 photos
hi
i have done this from a u/s grinder and it seems to work ok am loathe to publish anything
for fear of being ridiculed by some of the better engineers out there but if you are interested
you can contact me no problems
cheers
charlie m
Skarven19/12/2011 08:28:01
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93 forum posts
11 photos
Hi
 
Ian wrote:
Presumably the grinder input shaft is actually the motor armature spindle so if you ditch the motor you will have to engineer something to hold the gear.
 
I think it should be possible to remove the motors rotor from the shaft and then make an adapter that fits into the ISO30 shaft. Then I can use the motor bearing in the gearbox end as is, and support the 'upper end' of the shaft in the mill. I would have to sort out how to fasten the ISO30 adapter to the motor shaft. A key or maybe Loctite?
I could use the ER32 adapter with a suitable collet, but that would require a very long adapter for the grinder body. If I turn the outside of the grinder stator, I could make a simple adapter by turning one end for the quill, the other for the turned and cut grinder stator. There are so many possibilities, so this will have to lie 'working in the background' for a while. I'll be back with some pictures later on.
 
One possible solution would be to make fixture for the whole grinder with motor.
But mounted on the quill it will at least look ugly
 
Charlie:
I do not think that you will be ridiculed by some of the better engineers on this forum. I have only seen friendly and helpful responses not only to my own questions, but to all generally as well. That is why I like this forum so much.
Please put in a few pictures if you have them. To a 'want to be engineer' it is interesting to see other people's methods and solutions.
Versaboss19/12/2011 10:35:40
461 forum posts
51 photos

Skarven, what I don't grasp at the moment is which side of the angle grinder gear you want to use as 'input' and which as 'output'. The a.g. motor is geared down at least 4:1 or 5:1 I think. So either the mill has to run fast and a small cutter is still too slow, or vice versa?

Greetings, Hansrudolf

Ian P19/12/2011 11:08:42
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2452 forum posts
101 photos
Posted by charlie murphy on 18/12/2011 23:06:02:
hi
i have done this from a u/s grinder and it seems to work ok am loathe to publish anything
for fear of being ridiculed by some of the better engineers out there but if you are interested
you can contact me no problems
cheers
charlie m
 
 
Charlie
 
The last thing you should do is worry about what the others think! Regardless of how poor your opinion of what you have done, be assured there are plenty of people who have done jobs that are a complete mess. If solves the problem for that person that is all that matters.
 
I for one would be interested in how you mounted your gearbox.
 
Ian
 
 
Skarven19/12/2011 11:28:33
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93 forum posts
11 photos
Hi Hansrudolf
I intend to use the input as input. My mill has a maximum of 3200 rpm, so with 5:1 i would still get 640 rpm and that should be enough for most sawing with a 100 or 125mm saw.
I'm also installing a VFD that might give me a little bit higher rpm.
Ian S C19/12/2011 11:32:46
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7468 forum posts
230 photos
As far as speed goes, if you run the mill at 5/ 600rpm, it should be about right for a slitting saw on mild steel. You havn't had a gear box fail! I suppose the cheap grinders that we use in our comercial workshop get a bit of excess use, they only cost about $NZ15 (about 8 pounds), they last about a year, then the bloke I work with tries to get me to fix the b****y thing, so between the ones with burned out motors, and the ones with blown gear boxes, I usually get one working. It might be worth changing the bearing on the output side. Ian S C
Skarven19/12/2011 12:37:18
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93 forum posts
11 photos
Hi Ian
I guess the commercial workshop use is more intense than my hobby use of them, but they have seen quite hard work, especially when cutting steel. That is when they burn out too!
If you have a good nose, they will often give you a "smelly" warning before they start smoking!
 
I have begun using a power meter to have an indication of the load. You get a cheap one for about £10 where you can read Volts, Amps and Watts. If you look at the power from time to time when using it, you will after a while know how much you can push the machines. This is useful for all kind of machines, mills, drills, lates, grinders... This may be the reason why I don't burn them. This will also probably be kind to the gearboxes.
Gray19/12/2011 17:17:06
1040 forum posts
13 photos
Having destroyed a couple of 'good quality' angle grinders, their main failing is the gearbox or the bearings.
Angle grinders are not built to be accurate or particularly efficient in the transfer of power/drive from the motor to the spindle. You will find that the gearbox is the biggest source of noise in these machines and is testament to the poor fit and quality of the gears.
 
I would look for a proper right angle drive for your mill.
You didn't state what make/model of mill you have but have a look on ebay for a bridgeport horizontal drive adapter, they do come up occasionally and are well worth the money.
Alternatively, there was an article in MEW a few years back describing the construction of a right angle drive for a mill. I f you can't find it, I may have the details somewhere.
 
Anyway, as a recommendation - Don't use an angle grinder gearbox if you want accuracy and longevity
Skarven19/12/2011 19:01:28
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93 forum posts
11 photos
Hi Coalburner
The proper right angle drives that I have found cost something like £1700 + + +, and they do not fit my mill, a 'Tongli ZX45 Super'. That price is not very far from what I payed for the mill.
 
Even if the gearbox of the grinder does not last for long, at a price of £17 I could buy a few to swap when they wear out.
I do think that they will last for a while though, because the power they are made for is 900 watts at 11000rpm input. The mill is 1100 watts at 3200 rpm, giving about 4 times the torque, and at lower speeds I can certainly overload the gear more than that.
But you do not use the full power for normal operation, so if I keep the power at let's say 500 watts it will be relatively easy on the gear.
 
I think
 
The cutting operations that I intend to use this setup for, does not have any accuracy criteria, so the question is if it is good enough to not brake the slitting saw.
 
I will have a look in MEW for the angle drive, but the gear cutting is still a bit scary for a beginner!
wotsit19/12/2011 20:21:34
188 forum posts
1 photos
Hi, Skarven
 
There is an article/design on constructing a vertical to horizontal slitting saw drive in ME Vol 196 no 4276 (23 June - 6 July 2006) which may point you in the right direction - this was fitted to a Warco Mill, but could probably be made to fit whatever you have.
 
In our local markets (Not UK) it is possible to buy spare parts for almost any angle grinder, and there are many different sizes of these gears available. My mill had quite a lot of backlash in its Z drive, and I built a modification to it which used a set of these gears. I removed the modification very quickly, because the gears are anything but precise!. They appeared to be finished 'as cast', and it was impossible to get a smooth drive using them, despite all the bearings being fitted with ball races.
 
At first, I thought it was because these were cheap replacement gears, but later I had the opportunity to dismantle a Bosch (expensive) machine, and found that its gears were also finished 'as cast'. I guess they may wear smooth with time (!), but then will doubtless have lots of play, since there was no adjustment. In my opinion, a large part of the loud noise these evil tools make is due to the state of these gears.
BERTO19/12/2011 22:55:21
46 forum posts
Hi, Skarven
Wouldn't it be easier to buy or make a small metal bandsaw or power hacksaw ?
That way you are not upsetting the set up of the mill to cut materials , i use my bandsaw and it is set and forget until it switches itself off leaving me to nd to other duties .
 
Ian
 
 

Skarven20/12/2011 04:00:57
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93 forum posts
11 photos
Hi wotsit
I agree that most of the sound of these grinders comes from the gear, probably because of the rather low quality. But this will not have a major impact on the sawing operation. I would be more concerned for the quality of the bearings.
 
Ian
Yes, it would be easier, but they are also quite expensive and at least the power hacksaw has a limitation when it comes to long cuts, say 500mm. I already have a 'metal cutter' which is more like a 2200w angle grinder with a 355mm cutting wheel in a stand. The longest cut I can do with this cutter is about 140mm. With an angle gear and slitting saw I can do cuts as long as the mill table's travel, about 600mm.
 
A band saw would of course be the answer to all problems. I have one which will cut aluminum of about 2mm thickness. I think that a bandsaw that can cut, say 25mm of steel for 300mm, would be quite expensive.
Les Jones 120/12/2011 09:24:31
2188 forum posts
150 photos
Hi Skarven,
I spotted a right angle gearbox on Ebay. It does not say what ratio it is but you could ask the seller. It looks more substantial than an angle grinder gear box. The Item number is 290640471114
I also noticed that you planned to use the grinder gearbox in reverse. I think that way would be increasing the speed not reducing it.

Les.
Ian S C20/12/2011 11:09:57
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7468 forum posts
230 photos
About 15yrs ago I built a power hacksaw, only cost was a 1"x 12" blade, the saws gone now,I have a bandsaw now, but the old saw was good. Ian S C
Skarven20/12/2011 14:31:57
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93 forum posts
11 photos
Hi Les
The guy with the gearbox only ship to the UK, so Norway is out! But this gearbox looked really good.
 
No, I want to use the gearbox the 'right way' with the mill shaft connected to the grinders motor shaft,'input shaft', and the saw at the output shaft, where the grinding wheel is. I think the torque would be reduced to much the reverse way.
Stub Mandrel20/12/2011 16:25:11
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4311 forum posts
291 photos
1 articles
I dismantled a cheap angle grinder to get the gears for the 3.5" gauge shunter project.
 
It burnt out as a result of cutting a surface plate out of granite composite kitchen worktop...
 
I was stuck at the quality of both bearings and the helical gears - not aerospace stuff but smooth and no noticeable play. It would be very easy to replace the motor spindle and use the front end of the case to ensure proper alignment. The 10mm bore bearings on the output shaft could easily be replaced if you wanted better quality ones.
 
Neil
Les Jones 120/12/2011 17:17:08
2188 forum posts
150 photos
Hi Skarven,
I suspected from your name that you may not be from the UK but your profile did not show which part of the world you are from. I thought it worth mentioning just in case you were in the UK.
 
Les.

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