Small horizontal mill ID, celtic knot logo?

[RainbowsParticipant @rainbows]

After failing to buy an Elliott shaper and having a strongly pent up desire to make flat things I impulse spent £300 for a mill, 30 cutters and a 100 mile round trip delivery drive from the seller.

Not sure if I over paid for it. The search for milling machines hasn't turned up anything better in the past and I can't get an X0 micro mill with table for that money so I don't think I will regret it strongly.

Any way here are the seller pics

Can anyone recognise the make? On the side view I can see a sort of celtic knot (I think thats the right word) but aside from that no numbering or lettering.

[RainbowsParticipant @rainbows]

[Ady1Participant @ady1]

If you do this game for long enough there's pretty much nothing you regret buying

Looks neat and chunky, but not too big, the vice may be slightly overspecced…

Edited By Ady1 on 27/07/2017 01:13:35

Edited By Ady1 on 27/07/2017 01:14:32

[TrevorKParticipant @trevork]

The Celtic knot symbol is that of the Denbigh Engineering Co. You’ll find some info about them on lathes.co.uk where there is currently a Denbigh Miller for sale. I’m currently restoring a Denbigh mechanical hacksaw.

[peak4Participant @peak4]

Posted by TrevorK on 27/07/2017 01:31:16:

…… I’m currently restoring a Denbigh mechanical hacksaw.

A fine beast, I've just finished putting one on the road myself.

Had me fooled for a while as I didn't realise it should cut on the push stroke.

Bill

[NIALL HORNParticipant @niallhorn50878]

It's a Stafford knot – see Wikepedia. It also used to be the logo of the Bourne and Hollingsworth department stores – but only senior members will remember them. The Southampton branch used to have a good tea shop!

[Neil WyattModerator @neilwyatt]

Indeed that's the Staffordshire Knot!

Neil

(In Staffordshire!)

[Adrian JohnstoneParticipant @adrianjohnstone89946]

See also the Wiki page on the North Staffs Railway which was called the Knotty, and has knots on its crest.

**LINK**

Adrian

[Clive FosterParticipant @clivefoster55965]

Looks to be a Debnigh H4 auto. One piece cast overarm assembly rather than the two part rod and bracket type shown in the picture near the bottom of this page **LINK** suggests its an older, pre war one.

Almost brutally simple, all the essential bits and nowt more. Tough, durable and decently made, albeit aimed at the less prosperous end of the market. Will do what it says on the tin. Maybe a bit slower than a more modern machine but it will get there.

Assuming no serious wear in the slides thats a good buy. Simple engineering means you can make replacements for pretty much anything thats worn.

Clive.

[RainbowsParticipant @rainbows]

88mm of Y travel seems a tad small, an X1 has 145mm. X and Z are fairly similar between the two.

 

Out of curiosity what are the missing features that a more up market horizontal mill would have? I have a surface level understanding of how they are used but beyond that don't really have a clue on the finer points. 

Edited By Rainbows on 27/07/2017 21:20:29

[Clive FosterParticipant @clivefoster55965]

Horizontal mill doesn't need much Y travel as all the work is done on the X-axis and cut positions are largely set by the width of the cutter(s) and their position(s) on the arbor. Y-axis is more to bring the work to the correct position under the cutter(s) than for making a succession of cuts each suitably offset from the last. You can do such if needful but its not the way the machine is intended to be used.

Vertical mills need decent Y-travel because the the cutter needs to cover most of the table area. Which is what makes them so versatile. Horizontal mills are fundamentally production devices which is why so many of the smaller breed have lever operated slides. In many ways the ideal is to do the job in a single pass.

Big, powerful horizontals are chip generators par excellent and can pretty much bury you in very short order given the right sort of job.

Clive.

[not done it yetParticipant @notdoneityet]

88mm of Y travel seems a tad small, an X1 has 145mm.

It'a horizontal, so comparing with a vertical mill is not too fair. You can only drill by 88mm, but you can flat (really flat!) a workpiece with a 150mm wide slab cutter in one go, which you cannot do so easily with a flycutter on the vertical (or this one either) without very careful tramming. Cross travel on the vertical is the vertical travel on the horizontal.

Vertical mills became more popular because they are easier for more manipulations, but you can't put six different cutters on a vertical mill at the same time, like you could on a horizontal.

It looks robust and could be driven by a VFD for extra speed control. Motor will likely outlast quite a few on the chinese offering.

Does the table feed work? An extra, if available, on an X1.

If those cutters are sharp, you have done very well. It will last longer than an X1. Centecs have the option of fitting a vertical head, so a bit of a leap ahead – but the downside would be finding a good vertical head for what you paid for the job lot.

[RainbowsParticipant @rainbows]

Have my eye on a fairly big slab cutter on ebay. Using all these old imperial cutters is gonna give my metric minded rain an aneurysm though. I have an old lathe headstock which I might butcher into a vertical head with some chinese bevel gears.

Imagine hoisting a paint can full of coolant and a hose might be good for a cheap suds.

I have a 1/3 HP 3 ph motor spare and a bunch of VFDs up to 1.5kw. Didn't check the current motor power though it is single phase. What sort of power should I be aiming for?

[RainbowsParticipant @rainbows]

Quick question, what sort of cut should this be able to take?

Attempted to use a slab mill on a 90mm wide cast iron piece. Can't take any depth of cut without either the belt slipping or the motor stalling. Its a 1" belt on a 2 1/4" wide pulley and the tension pivot is really gummy so I guess a new belt is first port of call, failing that a new motor and poly vee pulleys

[not done it yetParticipant @notdoneityet]

Never a quick answer unless the detail is present in the question. Trying to cut full width? Arbor rpm? Feed rate? Diameter of cutter? How many teeth?  Condition of cutter?  Motor power? All relevant, I would suspect. Even the material will make a difference.

Why not try with something a little (no, a lot) narrower, as a starting point? A stalling motor will not be cured with different belts.

Edited By not done it yet on 18/08/2017 18:07:14

[Martin WhittleParticipant @martinwhittle67411]

Agree absolutely with NDIY. You refer above to a 150mm width slab cutter – I take it that you are not trying to drive anything like with this mill. I question whether it would fit, but whatever motor power you have on this mill, it would be insufficient.

[BazyleParticipant @bazyle]

Imagine the set up inverted as it were. A 3 in dia cutter 1/4 wide cutting 10 thou deep is the equivalent of turning a 3 in bar on a lathe and taking a 10 thou cut at a feed of 1/4in per rev or 1/4 in deep at 10 thou feed per rev. Would a 1/3hp motor handle that?
Think of a reasonable cut on a lathe for the motor size and work out the volume of material removed and work backwards. A spiral ground slab cutter is slightly more awkward to estimate as the width of tooth in contact is dependent on the depth of cut too.

[RainbowsParticipant @rainbows]

Will try a narrower cutter on Monday.

There isn't actually any data plate on the motor so everything is by guess and feel which being new to the mill isn't easy.

 

The cutter is a 4" long, 3" dia cutter. Might have overestimated the ability of the miller just a tad

Bazyle, thats actually a very nice way to think of it. Would the amount of cutter teeth divide the load compared to a lathe though? Either way that helps a lot. 

Edited By Rainbows on 18/08/2017 19:17:16

[Clive FosterParticipant @clivefoster55965]

Wet finger in the wind estimate for power needed to machine cast iron is 1 cubic inch per minute per horsepower. More likely a little less. Table in the middle of this page :- **LINK** looks to be a useful quick summary.

That assumes you are operating the cutter at an appropriate speed and feed. Hopefully someone here has a good reference for HSS slab and side and face cutters when used on smaller machines.

I'd guess that it was intended to put around 1 HP through the spindle in normal factory service. Have no doubt that Mr Oppress the Workers Capitalist boss would put as much power on the input side as he could. Despite which Penelope Piecework would probably stall the poor thing on regular basis.

Clive.

[Dave HalfordParticipant @davehalford22513]

I have run a 3 "wide 21/2" dia slab mill on a Centec 2a with 1/2 hp motor. I only tried a light 3" cut of 2thou on alloy.

Shavings got thrown everywhere.

That said the slab is sharp and the shafts are free running. Its surprising how much stiff counter shafts and tensioner wheels soak up the power.

Is the cast iron machineable or are you trying to cut a hard spot You may have blunted the cutter.

Steel would be a better first choice to try.

BTW I have a T&LM lathe that took a 1" flat belt – the pulleys are about 1/16 wider than the belt so as your 1" looks lost on those pulleys it is too weedy to drive the mill, bit like your motor

[RainbowsParticipant @rainbows]

This has the potential to be its own thread but what for not taking over the forum will just turn this into Denbigh Mill Questions General.

I'm installing a bigger motor with VFD to the mill and want to overhaul the countershaft while I am at it.

For speeds of 504,300, 178, 84, 50 and 30 RPM on the spindle I need to make the spindle go at either 300 or 50 RPM. The fast 3 for small cutters and endmills and the slower range for the bulk of the horizontal milling tools. As is the spindle is too fast for most horizontal cutters.

The motor which I got is a 1.5kw 1420RPM model. The overkill power is to let the VFD turn down the speed without running out of power.

Issue is that the ratio from motor to countershaft is 4.7:1 (not too bad) and 28.4:1 (uh oh). Making a 6:1 then 1:4 compound pulley would be a pain for switching between speeds. My current idea is to make something like the back gear of a lathe on the countershaft. Have the 4.7:1 ratio by pulley then a back gear of 6:1.

Would rather not have to buy 4 gears and make an eccentric shaft though. Can anyone recommend a different solution?

[clogsParticipant @clogs]

Rainbows,

a bit late, just got home but I'd say u got a bargain……..

Clogs

[Clive FosterParticipant @clivefoster55965]

Rainbows

A belt drive version of the conventional small lathe back gear layout works well and isn't stupidly hard to configure. Basically two shaft system. One input/output power shaft and one outrigged shaft to carry the back belt pulleys. I did one many years ago and the only mildly tricky part was sorting out the direct drive / back belt drive selection. I used a pin system like the usual small lathe. These days I'd work a bit harder to sort out a dog clutch. Ordinary Vee belts back in those days. Poly-vee would have made life much easier as being simple to make and able too e much smaller.

Basic system is 4 pulleys two large and two small. Small pulleys drive the large ones. Much easier if they are identical pairs but it can be done with different sizes. Fix one pair together at a suitable spacing and either mount on a free running shaft or sit bearings inside the pulleys and use a fixed shaft. 6 of one, half a dozen of t'other really but overall I figure a fixed shaft is probably marginally easier. Especially if a bit of cut'n try engineering is envisaged.

The other large pulley is fixed to the power shaft and its corresponding small pulley is free running on suitable bearings. Drive goes either direct to the power shaft or to the free running small pulley. I put my basic speed reduction pulley in the middle on a free running bearing and pinned it to either the large pulley for direct drive or the small one for back gear. It worked but was somewhat inelegant and arranging access to the drive pin was bit tricky. Mainly due to not thinking the whole thing through properly in the first place. These days I probably use a dog clutch.

Clive.

[RainbowsParticipant @rainbows]

Ah thats a good idea, I imagine that a poly vee belt with quite a few ribs can transmit quite a lot of torque. Will have a google around to try and find max torque, and check feasibility.

 

Well it would kind of work but not well. For 100 RPM on a 50mm pulley the kW per rib is like 0.01-0.02. Don't think 100 rib belts are in common manufacture. If I were switching between a very high speed and a medium speed it would work great but not here.

Edited By Rainbows on 10/09/2017 22:22:00

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