New guy from Norway, planning a Bonelle grinder

[FulmenParticipant @fulmen]

Greetings everybody. As the title says I'm not from the UK, but that shouldn't matter too much right? There is just no good forum for this in Norway (other than some Facebook (shudder) groups.

My reason for joining is that I'm planning a Bonelle/Quorn build, and there seems to be a fair bit of experience with them here.

[FulmenParticipant @fulmen]

[DaggersParticipant @daggers]

Welcome Fulmen.

Aways a warm welcome to a fellow machinist from anywhere in the world.

Ask your questions and there is always help and advice.

Look forward to seeing you progress.

[OldironParticipant @oldiron]

Hi Fulmen. Welcome to the forum. You should find info & help here for your build.

regards

[FulmenParticipant @fulmen]

Please don't hold your breath waiting for that, it's a loooong project and I'm just getting started.

I'm still in the process of modelling everything, and I also need to rework everything into metric units and dimensions. I'm also looking for suitable stock material which so far is pretty much unobtainium. I really would like to get cast iron for the base, but I'm also considering aluminum.

[BizibilderParticipant @bizibilder]

Hi Fulmen – You will find that there are already metric plans/drawings for the Bonelle online. The thing to watch out for is that you get the latest version of the drawings (all those that I have found are OK but the latest has a few notes and one or two missing dimensions corrected.

The "Quorn owners group" on groups.io has the latest drawings and is a good resource of notes and pictures of various builds. Hope that helps. It is a good project but does take quite a while to build – as I am finding out .

[John HaineParticipant @johnhaine32865]

https://groups.io/g/Quorn-Owners/topics

**LINK**

[FulmenParticipant @fulmen]

@Bizibilder & John Haine: Thank you that's very useful.

I'm working off the PDF by Don Williams, and I think I will model the original design first in Fusion 360 just to get a good reference. Besides I need the practice. The metric conversion doesn't look that hard, I haven't found any inherent geometry that can be screwed up. But it's nice to have something to follow, even if I choose to alter the design somewhat.

The real problem seems to be the materials for the base. Obviously cast iron is the top choice, but square stock is impossible to source here. Making it from round stock isn't too appealing either. There are some suppliers in the UK, but the shipping cost is pretty horrendous.

Has anybody seen a build with an aluminum frame? It would make it easier to stow away between use, and casting it myself isn't entirely out of the question.

[DaggersParticipant @daggers]

I the past i have fabricated a machine base from 6mm plate with a frame of rectangular bar steel 20×10, used edge on. With a couple of cross brace pieces from the same material. I did not have a welder so used 6mm countersunk hex screws through top plate into the rectangular bar.
It was a compromise but worked well.

If large material is not available or too expensive then fabrication can be useful.

Best of luck.

[lfoggyParticipant @lfoggy]

Hello and welcome.

I built a Quorn Mk3 from the Hemingway kit and plans. Its a great project and the quality of the kit and castings is excellent. Might well be no more expensive than getting all the parts and materials together seperately.

[Richard MillingtonParticipant @richardmillington63972]

Aluminium base – I made my copy from what I had lying around, photo's here:

https://www.model-engineer.co.uk/albums/member_album.asp?a=58414

I did get a copy of the construction book with some other books I bought, it was / is very useful. Fit a cover over the front bar and I use a vacuum cleaner as well – it does wonders keeping grinding dust down.

Things I would change – put the 0 pointer at the front of the degree scale, under the arm may have been the easiest to machine out of one lump of steel but is a PITA to use.

[FulmenParticipant @fulmen]

@ Richard Millington: Have you ever regretted the choice or felt that a cast iron base would have made any real difference?

[DMBParticipant @dmb]

Hi Fulmen, welcome to the forum.

Assuming you're still living in Norway, how about taking a holiday in Britain. Visit museums or railways of interest and personally collect all the heavy bits of metal needed. Presumably, if you use a ferry you could side step the airlines exorbitant charges for weight of baggage. View various suppliers websites and arrange for purchases to be collected. Just a thought.

Good luck with your project and please let us all know how you get on with progress reports.

Regards

John

[JohnFParticipant @johnf59703]

Hi Fulmen and welcome, not that it really matters but out of curiosity where in Norway are you ? I saved this link some time back and maybe it will be useful to you ? https://www.hobby-machinist.com/threads/a0-bonelle-plans.6664/

Good luck with the build

John

[egaParticipant @ega]

Posted by Fulmen on 29/03/2023 21:05:32:

@ Richard Millington: Have you ever regretted the choice or felt that a cast iron base would have made any real difference?

The front bar, presumably of steel, slides in the base so that aluminium may not be ideal.

[FulmenParticipant @fulmen]

I don't know how Richard solved that, I was thinking of brass sleeves for the moving parts.

[Harry WilkesParticipant @harrywilkes58467]

Welcome to the forum

H

[Richard MillingtonParticipant @richardmillington63972]

Aesthetically much nicer made in the Hemingway castings, but I had most of the materials from the works skip during my working life so it was made of what I had in the garage, aluminium and steel. The only things I had to buy were the ER32 collet, magneto bearings, drive belt and grinding wheels.

Yes you will get more wear in the aluminium than cast iron, and the dust covers are essential, but I expect it will last my life out! The front bar just runs straight in the aluminium end pieces, the centre lower boss has PB sleeves in it but as this is usually clamped to the bar to touch up my milling cutters I doubt it would make much difference if it ran straight on the alloy.

The dust cover is zip tied onto the aluminium (look for the grooved mounts in the photos) and the slots are also filled with RTV to prevent dust / grit ingress that way.

If I had to pay for the materials I would have made it nearer to the Bonelle design, but fabricate lower sections in steel with welded in bosses then machine accordingly.

[FulmenParticipant @fulmen]

I did consider a castings kit, but I'm not really a model builder. Getting everything lined up right seems to be big part of the challenge and I kinda detest creative setups that could break a casting. Building it from scratch provides more leeway for solving things my own way.

While it was a hard sell I'm going for aluminum. My local dealer actually has 50mm square aluminum in stock, 6068 T6 IIRC. That should do nicely if I ever get the drawings done. I'm about 50 parts in so far…

[FulmenParticipant @fulmen]

Here's the spindle assembly all drawn up:

[gerry maddenParticipant @gerrymadden53711]

Fulmen, nicely drawn spindle. I think you might need to extend a few of those threads to make it assemblable, but I'm sure you realise that already . If you are making this yourself then here are a couple of more helpful points to consider:-

1) The solid abutment within the housing could be made as a separate sleeve which is then located in place by a couple of screws from the outside. This could be easier to make, and potentially more accurate too in terms of squareness of the important right-hand abutment face. (This is how J&S do it on grinding spindles.)

2) You have incorporated a pair of AC type bearings which is the traditional choice for such spindles. However, its extremely likely that a pair of conventional deep-groove ball bearings will be perfectly adequate here, technically, and will of course be significantly cheaper too. By selecting a C3 clearance grade, provided you shaft interference fits are not excessive, they will automatically become an approximately 15deg angular contact once loaded by the spring-box arrangement.

Gerry

[FulmenParticipant @fulmen]

Thanks, that's good advice. The drawings aren't checked for errors yet, and they will be "metrified" before construction. So plenty of time to add my own errors

[John HaineParticipant @johnhaine32865]

Nice drawing – essentially a Quorn type I think? The Quorn has an 8mm taper that matches a standard watchmaking type of collet I think – these collets are quite hard to find and expensive. You can of course just use a plain tapered mandrel but if you were thinking of fitting collets as well maybe consider an ER16 nose? You could use it with a drawbar for wheel mandrels and have the option of collets.

[FulmenParticipant @fulmen]

Wow, this turned out better than I could have hoped for. Got a call today from a nice member of this forum that had ductile iron for me. He could even cut it to the rough shape for me.

Guess I'm all out of excuses now

[FulmenParticipant @fulmen]

I'm a bit stumped now. I've been working on the wheelhead and something doesn't add up right:

The wheelhead guide (Drg 11, Det 1) does not line up with the jack screw (C10 Det1) and the square guide rod (C11, Det 2). I've double and triple checked the drawings and I can't find any mistakes. Also the guide collides with the mounting bolts for the wheelhead arm (C3 Det 1). I've checked both Don Williams original PDF and this metric one: http://www.mosoft.nl/slijpmachine/A0%20Bonelle%20TCG%20drawings%20Metric.pdf

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