Unmachined Kit Suppliers

[UncouthJParticipant @uncouthj]

Hi there folks…

Couldn't find any existing threads so thought I'd start one for general thoughts and recommendations on model kit suppliers.

Currently I have:

Macc models – have ordered a few bits but not received yet so can't speak to quality, but they have been very responsive to communication so far which is always a good sign.

Hemingway Kits – not dealt with yet but do like the look of their kits.

Stuart Models – again not dealt with yet, but imagine only good things being one of the oldest in the business.

Any others anyone can add would be much appreciated.

Jay

[UncouthJParticipant @uncouthj]

Recommendations

[KWILParticipant @kwil]

Noted. Stuart models name may well be very old but present owners are not.

[BazParticipant @baz89810]

Macc models only ordered rew material but quick to send.

Hemmingway, had quite a few of their kits but all the bar stock in mine has been dead to size or slightly undersize

Stuart, not one of the oldest really, changed hands and are not as good as the older stuff, seem to produce quite a few castings with hard spots.

[UncouthJParticipant @uncouthj]

Good to know! Exactly the kind of info I was hoping to collate thanks folks

[JasonBModerator @jasonb]

Polly (Bruce) engineering do a large range both their own and also the designs of Anthony Mount. Stocks are now limited so you need to order in advance

Reeves also do a large range many of the classic older designs

Could not fault the last few castings I have had from Stuarts over the last year nor the Reeves one come to that.

[UncouthJParticipant @uncouthj]

Nice one thanks Jason. Been looking for larger engine kits!

[JasonBModerator @jasonb]

There is also Blackgates who do some of the old Clarkson designs, the 2" bore ones are a good size but they don't have an upto date catalogue online at the moment.

Forrest Classics import the PM Research range which are popular with the US Youtube builders

Engineer's Emporuim have some larger stuff though not always on their website

[noel shelleyParticipant @noelshelley55608]

Stuart Models has been owned by Bridport Foundry for about 8 or ten years. Apart from old stock, they make their own castings so IF there's a problem just send back and it will be replaced.. If you have the misfortune to spoil a casting spare ones are available, and their in the UK.

I dealt with Forest Classics recently, sent the right part, quick, and very helpful. Noel

[Nigel Graham 2Participant @nigelgraham2]

I have now built two Hemingway Kits – a between-centres boting-bar set and a 'Worden'-pattern tool-and-cutter grinder.

I had some difficulty with holding some of the bar-stock pieces because they are cut nearly to finished length, and for one or two I used my existing stock instead.

Other than that I have been very satisfied with them.The drawings have rendered 3D images alongside the orthographic elevations, to help you, and clear guidance notes on making the parts (though you may need use your own methods at times, to suit your own workshop equipment.) The designs appear to be such that the parts can be machined entirely on Myford or similar lathes, though a milling-machine also would be a definite advantage.

The T&C grinder comes with the sheet-metal parts finished apart from deburring, but the protractor scale on the table is engraved with the divisions but not the numbers. The instructions show how to make a simple punch-guide for stamping them. I used an old Vee-block; not one of my decent ones but a "waif-&-stray" item.

(Write the numbers on in felt-tip pen first, on any similar task…)

[Dave WoottonParticipant @davewootton]

Friend of mine recently completed a Stuart 10V and has just received the castings for Victoria, he had no problems with the 10V castings and the Victoria ones look very nice, these are from Bridport Foundry. The Victoria ones look so nice I was almost tempted away from loco building, only just managed to resist!

There was a time a few years ago when Stuart castings seemed to be very variable in quality, but since the change of ownership have much improved.

I built the R&B gas engine from Polly castings and both the castings and service was excellent.

Good luck with your choice, hope you enjoy the build

Dave

[UncouthJParticipant @uncouthj]

Posted by Nigel Graham 2 on 17/09/2022 17:15:13:

I have now built two Hemingway Kits – a between-centres boting-bar set and a 'Worden'-pattern tool-and-cutter grinder.

I had some difficulty with holding some of the bar-stock pieces because they are cut nearly to finished length, and for one or two I used my existing stock instead.

Other than that I have been very satisfied with them.The drawings have rendered 3D images alongside the orthographic elevations, to help you, and clear guidance notes on making the parts (though you may need use your own methods at times, to suit your own workshop equipment.) The designs appear to be such that the parts can be machined entirely on Myford or similar lathes, though a milling-machine also would be a definite advantage.

The T&C grinder comes with the sheet-metal parts finished apart from deburring, but the protractor scale on the table is engraved with the divisions but not the numbers. The instructions show how to make a simple punch-guide for stamping them. I used an old Vee-block; not one of my decent ones but a "waif-&-stray" item.

(Write the numbers on in felt-tip pen first, on any similar task…)

Have you completed the T&C grinder Nigel? How functional do you find it? I'm on HSS for my Logan as several people I've spoken to say it's far superior for the lower speed high torque machines. Not a fan of eyeballing anything that wants a specific angle, my mentals need it just so…

Jay

[Nigel Graham 2Participant @nigelgraham2]

I must admit I've not actually used it very often, yet!

The 'Worden" type T&C grinder is for lathe tools, and for the end- but not flute- edges, of end-mills and slot-mills. Sharpening flutes needs a more sophisticated machine with tool-axis centres and helix-follower.

It holds the lathe tools in a simple block with channels allowing the side and front clearance to be cut. It might grind the top-rake, but not easily due to access too the wheel. If you use tangent-tooling, which I have never tried, a T&C grinder would seem the better sharpener than a bench-grinder.

The T&C grinder is not for hogging great lumps of steel off an HSS blank. To minimise wheel wear, remove the bulk of the metal with a bench-grinder, use the T&C machine for finishing the surfaces to the accurate angle.

For grinding an HSS blank to a particular shape recently, I cut the bulk away with an angle-grinder fitted with cutting-disc! Then a bench-grinder – actually to finished size as the tool was not critical, simply for undercutting the shoulder end of a spigot to be threaded with the form ground on the other end of the same blank..

.

For grinding HSS lathe-tools you don't need a full T&C grinder unless working to critical angles, such as cutting threads. The clearance and rake angles are not too important for most materials, within a degree or so is usually near enough; but the edge sharpness is the important bit. The clearance has to go right to that edge.

One tool that does demand care is a parting-blade, for if its end is rounded or not at right-angles to the flanks (in plan) it can cause all sort of grief by trying to cut a chip wider than the kerf.An old error, and one that I took years to discover, is to grind a parting-tool at an angle to minimise the pip or burr left on the work-piece.

An insert-type parting-tool has a little V-groove along its top, tending to fold the chip inwards, but that would be impossible to give to a steel blade without a specially-designed grinder.

.

For an ordinary bench-grinder, a simple table with an adjustable fence you can set to specific angles, would greatly improve it for tool sharpening. The table and fence can be made to be set with angle gauges easily cut from thin plate. For plain turning, free-hand grinding the tool to a template or adjustable-square will often suffice, especially if you then carefully hone the edge to a good finish with a fine stone.

Harold Hall's Tool & Cutter Grinding, in Special Interest Publishing's "Workshop Practice" series, deals comprehensively with this topic, to the extent of offering designs for tool-rests that effectively make a bench grinder into a simple T&C grinder.

.

You often see that remark about HSS tools being "better" for low speeds. The machine's torque is only relevant for depth of cut (DOC), and all lathes have their limits for either HSS or carbide tools. A carbide insert can be worked at higher speeds than steel for the same material, but that is not the same as having to be. I have not found it a problem using carbide tooling at quite modest speeds on either my Myford ML7 or the heftier Harrison L5, for similar work diameter and material. (I often have the latter lathe ambling round at under 200rpm, as I estimate, with the 3ph motor still at a healthy 900 – 1000 rpm.)

It is usually easier to obtain a good finish with HSS if only because the insert tool is really designed for fairly specific materials and conditions, and seems to cut in a rather different way to a steel tool. This is particularly so if you find yourself trying to work some awkward stuff rather than good-quality free-cutting steel, and may need experiment a bit with tool geometry. HSS is also a lot cheaper!

I use both, but the HSS probably more than the ceramic-insert tooling.

[JAParticipant @ja]

I have used Stuart (years ago), Hemingway, Polly and Reeves.

Stuart designs are good with the drawings a bit cramped. Some of their designs are well documented. Now they are owned by a casting house the castings appear to be good but with a lot of flash. Some models are simple and some appear complex.

Hemingway Overcrank engine is very complex and has no documentation. The drawings are crowded and poor. The iron castings are of a good material but some parts are under size. These are bought in.

Polly Anthony Mount models are complex, well designed and documented. The castings were good, quality and slightly oversize. Reeves castings are bought in. The iron castings I have are slightly oversize but let down by chilled hard spots. Some of the kits offered have redrawn drawings to a high quality. The range of kits offered is vast. I think most have been documented, usually once in the ME two hundred years ago. Some are very well established designs

In all cases it would be wise not to rely on the supplied bar stock. I have always had to buy more and occasionally the metric or imperial equivalent has been substituted.

JA

Edited By JA on 17/09/2022 21:15:04

[SamsarandaParticipant @samsaranda]

My recent experience of Reeves castings are that they can be variable in quality, some cast iron ones that I have machined have areas that are so chilled and as such it’s like trying to machine glass, the gunmetal/bronze castings that I have tackled some have very hard outer skins which need cobalt drills to penetrate and inside the castings are voids some encroaching into finished areas. We have to realise that the casting process can have variable results depending on the foundry practices used by individual foundries and its never easy to produce very small castings consistently because of their size and the rapid rate at which they can cool being the source of problems. Model Engineering castings by virtue of their size could always be problematic and we have to accept there may be problems. Dave W

[DMBParticipant @dmb]

Last castings that I purchased were of iron from Reeves in 2018. They were for the GHT rear toolpost and the multi station toolholder to fit the tailstock. Both were with relevant drawings. Only recently got a roundtoit with the toolpost and found the casting was lovely to machine with no hard spots anywhere, not even on the corners.

May I suggest any doubtful castings be BBQd for an hour then thickly covered in warmed sand and left to slowly cool overnight, covered with a sheet of steel to keep dew or rain off. If push comes to shove, bench grinder or angle grinder to get under any hard skin. Done that before.

I don't use inserted bits. Just use brazed Carbide lathe tools on castings. They work perfectly on the Myford. My only grouse is that they seem to only be available with a sharp corner resulting in small lines like a fine thread. Years ago they came with a nice rounded end which left a smoother finish.

[UncouthJParticipant @uncouthj]

Cracking info there folks, hats off!

Really enjoying DMB's tip for treating questionable castings!

A big takeaway for me here is that I've been very much of a tooling 'camp' mindset in choosing HSS. I see now each have strengths and purpose regardless of machine. Gonna have to invest in some carbide and do some experimentation I think.

Cheers for the thoughts on the Worden grinder Nigel. Think I'll focus on making some improvements and jigs for the bench grinder first, before deciding how much milage is to be gained from a dedicated tool grinder.

More to the subject in hand… The near/under size bar stock problem seems all too common. If the stock is unsuitable it defeats the point of buying the 'all in' casting kits, surely? I mean I get there are parts where the dimension has more wiggle room, but still…

[UncouthJParticipant @uncouthj]

Another question arising from another thread…

At what point in dimensional ex-tolerance is it fair to say "this casting is crap, gimme another"?

I've seen several makers having to tweak dimensions a bit due to one casting or another, but surely there has to be a limit? The idea of compounding an error not of my making across a whole build gives rise to a bit of sick in the mouth, to be brutally honest…

[JasonBModerator @jasonb]

If you can't machine the surface to remove all the casting texture would be when it needs replacement if one is available. Also if there are faults in critical surfaces that show up as the casting is being machined then you could reasonably expect a replacement. Thin section castings can suffer from "chill" which is hardening when allowed to cool too fast and that makes them hard to machine, as they are small you can often heat treat them yourself but again could be grounds for a replacement or time to get out the carbide tooling.

Poor positioning of features such as bosses where hold down bolts may go is something you generally would have to work around as that is likely to be caused by the pattern and a replacement is likely to be no better

[Michael MooreParticipant @michaelmoore38916]

Chiltern Model Steam might be worth a look. The engine range they produce look very nice.

[JasonBModerator @jasonb]

I think all of Chiltern's offerings are ready machined

[Engine BuilderParticipant @enginebuilder]

My friend had some chilled castings recently from Reeves.

They refused to replace them as machining had been attempted!

How else to you discover this?

[JAParticipant @ja]

When I used the term “over size” I meant there was more than 0.020” on each surface to be machined. As said, this is to remove the hard skin. This is good.

Conversely, “under size” meant casting was already below drawing dimensions. Then you would have to use something like an epoxy resin to build it up to size. If the casting is gun metal a little piece of bronze, silver soldered in the right place, can rescue the casting. This is not so good.

Castings are fun!/?

JA

[Michael MooreParticipant @michaelmoore38916]

Posted by JasonB on 19/09/2022 20:32:25:

I think all of Chiltern's offerings are ready machined

Yes you're right. I was sure I'd saw prices on their website for machined and unmachined kits but no.

[Author]

Posts