Bentall Corn Mill

I've been looking for a small corn mill to run off my Lister D and I've eventually found this :-







It is a Bentall no.3 corn grinder and in relatively good condition apart from surface rust and corrosion on the grinding plates.It is a hand operated mill but I have seen ( on google) these mills converted to run off a stationary engine.The easiest way of doing this would be to take the hand drive wheel off and replace it with a pulley - however I would like to keep the wheel on as a feature, so am thinking of putting a V belt pulley between the wheel and the mill body.The drive shaft is 1" diameter,the length of the shaft up to the mill body is 3",the wheel hub is 2.25" - I think that it just might be possible to have only say 1.5-1.75" of the wheel hub actually on the shaft.What do you experienced members think?

Using Dr Sandors Universal Pulley Calculator, I think that I would need a 5" pulley -does that seem right? It strikes me as being a bit on the small side.

I am wanting to paint the mill in the original factory colours - under the surface rust the paint appears to be a pale greyish green/blue.Does anyone know what the original colour was?

Any thoughts/ideas/advice would be greatly appreciated.Thanks in advance.

i think i would put an external belt whel on the outside, problem is you have to watch the speed ratio.

I would think that a 12-14" pulley or bigger would be more like it if you run the smallest pulley you can get on the engine, running at 700 rpm.

At least that would seem to be about right for approximately 60-70 revolutions per minute as by hand.

The engine wouldn't know to stop when a feed jam occurs though, and I wonder if that could damage that nice nice grinder.
On the other hand.., it wouldn't nessesarily have to be grinding either

Just my two coppers worth, it's interesting

Regards, John.

You will find it very difficult to slow this down enough to be able to run it off a Lister D, I recently spoke to a chap with a couple of very old open crankers who had one of these mills and he warned me against them. The trouble is these machines are designed to be hand cranked and were never engineered to take the power or speed of an engine.

The best way of slowing it is via a radicon box or similar as you want it turning as slow as you can. Those plain bearings will not tollerate fast running, I have a Bentall OKB mill around somewhere and that is on my 'to do' list to put a reduction gearbox on it though I have no intention of actually milling with the thing!

Pete.

Just to say my bit you need to watch the speed very carefully as the handle in heavy and it's going to be spinning quite fast and centrifugal force will want to send that handle all over, so it will also need securing down very well. Also to agree with what's already been said about hand operated implaments are not designed to be run by anything but hand, I know a few that have pedestal drills set up and run off an engine and they say there fine but I would be a little bit worried if they were mine.

Stu.

Speed is an issue, but not the only issue. As you reduce the speed the torque goes up (someone else mentioned the word power). Hand implements were never meant to take all that power & torque. It will be fine though, if it's just idling, but as soon as something goes wrong, like a feed jam or a bearing gives out, there will be a lot of power & torque there, ready to pull it apart.

Just be careful.

Thanks guys for all the helpful replies - they are really appreciated.

This is not going to be as easy as I thought,my inexperience in this hobby showing! - so back to the drawing boards for me I think! I was looking for a small mill to actually use to produce flour for home baking but me thinks this is not the one to try and hook up to my 'D'.

I hadn't thought about a feed jam!!but thats a good point made.

Thanks once again.

Oh just one other thing - what is a radicon box? Being new to this hobby/interest I have never come across this before!

All the best,

Kev.

You can still use it to make flour, & it will still make a good restoration project.

People do convert hand wind machines to run off engines, & plenty get away with it with no problems, but it doesn't make it correct (in an engineering sense).

It's up to you what you do with it at the end of the day, but none of us want to see any harm come to you, your machine or anyone else for that matter, so we always tend to err on the side of caution when it comes to advice.

BTW, I think Pete meant a "Reduction" box (as in a reduction gear drive box) probably just a miss-type (unless it is a particular type of reduction drive box?).

Sorry, a Radicon box (or similar) is just a reduction gearbox with usually a right angle drive, it is used to provide a lower speed for impliments etc.
http://www.radicon.com/catalogues.php

Pete.

Foden wrote:Sorry, a Radicon box (or similar) is just a reduction gearbox with usually a right angle drive, it is used to provide a lower speed for impliments etc.
http://www.radicon.com/catalogues.php

Pete.

I didn't think it was like you to miss-type anything Pete. Your posts are usually very well typed. I must say though, I haven't heard of them either.

You may find you could add a simple safety device like a shear pin somewhere along the line of you wanted to use this seriously and keep it safe. I would strongly urge you to remove the handle if you are going to drive it off an engine though.

You can reduce speed another way via a countershaft. Have a small pulley on the engine to a larger one on the countershaft, then a small pulley from the countershaft to the mill. Many hand operated barn machines were converted to run off an engine via a line shaft so you would be replicating that. I'd say you would be looking at about 30rpm. I wouldn't want to try and turn that by hand at 60-70rpm, that's some going! So if you have your Lister D running slightly slower at say 600rpm with a 4" belt pulley to a 12" pulley that would reduce the countershaft speed to ( 600 times 4 divided by 12 = ) 200rpm, then with a 4" pulley to a 24" pulley on the mill the further reduction would be ( 200 times 4 divided by 24" = ) 33.33rpm. I'd suggest using flat belt rather than V belt for the final drive as they can slip if there is a jam but you would probably be best with a V belt from the engine pulley to countershaft if that is close to the engine, short flat belts are not too good.

Here are some pics might help you understand about a line shaft that's fixed between your engine and mill. You'd only need a small one with 2 pullies a large one and a small one.

http://aolsearch.aol.co.uk/aol/imageDetails?s_it=imageDetails&q=line+shaft&img=http%3A%2F%2Fwww.americanartifacts.com%2Fsmma%2Fadvert%2Faw9g.jpg&v_t=sb_uk&host=http%3A%2F%2Fwww.americanartifacts.com%2Fsmma%2Fadvert%2Faw9.htm&width=183&height=138&thumbUrl=http%3A%2F%2Ft2.gstatic.com%2Fimages%3Fq%3Dtbn%3AANd9GcRiR_Hl7PiK76zAHlKjrjgq5Dlcr--IX0XHJLq6qavvqMh7yE-2BH_IkAS7Sg%3Awww.americanartifacts.com%2Fsmma%2Fadvert%2Faw9g.jpg&b=image%3Fv_t%3Dsb_uk%26page%3D4%26q%3Dline%2Bshaft%26s_it%3DimageResultsBack%26oreq%3Dfa38925cd68d4bf495a886cb0712ed64%26oreq%3D40d7752f29964cf6bf8a7742b7e0d073&imgHeight=342&imgWidth=450&imgTitle=Line+shaft+with+5+pulleys+and&imgSize=40327&hostName=<a href=

Stu.

Thanks very much guys for the further very informative replies/suggestions.

I hadn't considered a line shaft but I can see the sense in this from a speed reduction and safety point of view, and also I like the idea of replicating what they used to do in earlier times.Getting a shaft should be easy enough but I am not so sure about the bearings.Still further food for thought!
I should add that I will be removing the handle otherwise I could end up with a machine like Boudicea's chariot!!

Kev.

You could use a couple of plumb blocks for the bearings. Two together will self align, you just need the right diameter shaft for the bearing and get a slot machined in either end for retaining circlips.

This is the type of thing you need (x2) but ignore the price as you can get them a lot cheaper or even a scrappy should have some in. It could need to be altered with collars or the line shaft itself may need it's size altered either way.

http://www.ebay.co.uk/itm/FORD-RS-ESCORT-SIERRA-COSWORTH-CENTER-PROP-BEARING-AND-HOLDER-/221140111241?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item337cfa4f89

Stu.

Something like this. The correct name for it is either a pillow block or a plumbers block. You can get even cheaper, pressed steel, ones, but these are cheap enough & should last for ages....

http://www.ebay.co.uk/itm/UCP-NP-Metric-Pillow-Block-Bearings-/320887516146?pt=LH_DefaultDomain_3&var=&hash=item4ab662ebf2

Try to use these if possible as they are self aligning, but you need 2 of them at least for each shaft. The bearing is mounted in the casting in a kind of eyeball-socket affair, hence why you need 2 of them.

Pick your sizes carefully though. A 20mm shaft would be easiest to get hold of, but you might have trouble getting a flat belt pulley to fit on a 20mm shaft (V belt pulleys can be had, very cheaply, for any size shaft, brand new, it's the flat belt ones which tend to be harder to find, so you might be better off finding pulleys first, then getting shafts & bearings to suit).

Also, as Ian mentioned, you will need to make sure the shaft doesn't come out of the bearings or any of the pulleys come off. Having a groove machined on the shaft for a circlip is a good way to keep it on there, most pulleys should hold themselves on there anyway.

Might be better off not going for a keyway on the shaft, as this would give you a bit of security if there were any problems (IE, if there were a blockage, the pulley would rotate on the shaft, rather than damage the machine).

If you could find a local engineer/machine shop he'd probably be more than willing to machine you up the right bits for a fair price. I think you'd be surprised at how cheaply it could be done. Also, getting one local engineer to do the whole job is better than listening to a load of different people on the internet with their various ideas (although all of our basic ideas have actually been very good up til now, there are many different ways to go about this, & different engineers will have different ways of doing things & over coming problems like end float, shaft fixings, pulley fixings etc etc).

Thanks nuts for putting the correct block up, I forgot about them so put the center bearing up just as a guide so he had some idea what he'd need to find.

Stu.

Stamford24 wrote:You can reduce speed another way via a countershaft. Have a small pulley on the engine to a larger one on the countershaft, then a small pulley from the countershaft to the mill. Many hand operated barn machines were converted to run off an engine via a line shaft so you would be replicating that. I'd say you would be looking at about 30rpm. I wouldn't want to try and turn that by hand at 60-70rpm, that's some going! So if you have your Lister D running slightly slower at say 600rpm with a 4" belt pulley to a 12" pulley that would reduce the countershaft speed to ( 600 times 4 divided by 12 = ) 200rpm, then with a 4" pulley to a 24" pulley on the mill the further reduction would be ( 200 times 4 divided by 24" = ) 33.33rpm. I'd suggest using flat belt rather than V belt for the final drive as they can slip if there is a jam but you would probably be best with a V belt from the engine pulley to countershaft if that is close to the engine, short flat belts are not too good.

Lol,

I just took a rough guess at the rpm, one per second seemed reasonable.
But I like the countershaft idea a lot better, that goes along with the older technology and may well make it so much more interesting.

John.

At the end of the day John all we want is for him to be safe. I know we've all said a little of what to do but I think at the back of everyones mind is... will it be safe, and I wish we could say yes but there's so many things to be considered we just don't know.

Stu.

stationary stu wrote:At the end of the day John all we want is for him to be safe. I know we've all said a little of what to do but I think at the back of everyones mind is... will it be safe, and I wish we could say yes but there's so many things to be considered we just don't know.

Stu.

Saftey at home while testing a pump , genny or belt driven equipment out is a must but i am one to when get someting to test it out of when im on the patio i cant peg anything down so i have been using peices of wood to act as packing to keep tension on the belt but the engine can move about a tad and erlier i had a belt come off and wrap itself over me luckly its when i was stopping the engine so just sort of high speed rolled onto me

and i have caught my finger in a belt once while the engine was running and ouch that hurt and lucky didnt break my finger .... was badly bruised and my nail fell off in the end .

So remember be safe and try not to make short cuts and it can be dangerous .

Matt

matt86 wrote:

stationary stu wrote:At the end of the day John all we want is for him to be safe. I know we've all said a little of what to do but I think at the back of everyones mind is... will it be safe, and I wish we could say yes but there's so many things to be considered we just don't know.

Stu.

Saftey at home while testing a pump , genny or belt driven equipment out is a must but i am one to when get someting to test it out of when im on the patio i cant peg anything down so i have been using peices of wood to act as packing to keep tension on the belt but the engine can move about a tad and erlier i had a belt come off and wrap itself over me luckly its when i was stopping the engine so just sort of high speed rolled onto me

and i have caught my finger in a belt once while the engine was running and ouch that hurt and lucky didnt break my finger .... was badly bruised and my nail fell off in the end .

So remember be safe and try not to make short cuts and it can be dangerous .

Matt

It's amazing the accidents that creep up on one, one minute you're having fun and the next all hell broke loose and yer in a panic and reality looks different then!
I learned some of my lessons the hard way also, and regardless of how we excuse things away or think it will hold for a minute.., time and fate do not wait for anything and leaving yourself open to posibilities is not a good thing and sooner or later you bite the big one!!!

I used to look at people who were careful and laughed at that, but being smart and careful will save the day eventually.
I'll tell my story some other day in some other post where it belongs, but I definitely am a believer in safety!

Thanks Stu for reminding us from time to time, it's invaluable advice you give.

I'm done now lol,
cheers, John.

We all take stupid risks and most have a tail to tell when we've been doing something and instead of turning the engine off or what ever we stick a finger where it's not wanted. (then were in the sh*t LOL LOL) and pay the price. Starting handles that can fly is popular but I think the most accidents occur when moving the engine mainly loading or unloading where just about most body parts can get hurt from toes upwards.

Lets becareful out there, Play safe,

Stu.