Involute Curve | 04/10/2018 18:23:04 |
![]() 337 forum posts 107 photos | Material Cast Iron, my guess is the original will have been hollow, in order to make to manageable.
Shaun |
Adam Harris | 04/10/2018 18:25:41 |
533 forum posts 26 photos | original is solid not hollow |
Adam Harris | 04/10/2018 18:35:39 |
533 forum posts 26 photos | Or at least the early one (the more curvaceous one) is solid . The later model has a more angular and slightly more bulky one which may or may not be hollow |
Neil Wyatt | 04/10/2018 19:06:32 |
![]() 19226 forum posts 749 photos 86 articles | Bloody 'ell! I thought you were planning something like this:
For a lump like that, it's possibly worth making your own pattern and getting a casting done. I doubt the price difference will be huge as that will mean so much less metal. Neil |
JasonB | 04/10/2018 19:12:06 |
![]() 25215 forum posts 3105 photos 1 articles | Not so sure Neil, recently picked up some castings and the foundry were charging £10 a kilo, Alibre tells me a basic L shaped blank will be 40Kg and you won't have any offcuts to use for something else. |
Adam Harris | 04/10/2018 19:16:08 |
533 forum posts 26 photos | Ha Ha Neill! That would indeed be a job! No this is quite a simple affair albeit more voluminous. Are you still recommending EN1A pb? |
Adam Harris | 04/10/2018 19:18:15 |
533 forum posts 26 photos | Or if casting, what spec of material and anywhere recommended to do it within 100 miles of Oxfordshire? |
Adam Harris | 04/10/2018 19:22:29 |
533 forum posts 26 photos | I thought a common commercial size billet cut down to rough size with my Rapidor saw which I hardly ever get a chance to use, would be the cheapest way but if casting is cheap then I am all ears... |
Chris Evans 6 | 04/10/2018 21:52:59 |
![]() 2156 forum posts | Make a simple pattern from polystyrene which will be burnt out of the sand box. This is how I made my new lathe cross slide. Speak to Nigel at Coventry Castings. |
Adam Harris | 04/10/2018 21:59:09 |
533 forum posts 26 photos | Thanks Chris, I will call him tomorrow. And what spec of material would you recommend casting with? |
Marcus Bowman | 04/10/2018 22:25:54 |
196 forum posts 2 photos | The ideal material for a real machine tool would be Meehanite, which dampens vibration, but I imagine that might be a tad expensive. In that case, spheroidal cast iron ('ductile' iron) would still give good results. I have no experience of specifying grades, but this site gives advice: and I guess a foundry would advise. There seem to be plenty of companies advertising that they either cast from patterns, or sell large section bar. West Yorkshire Steel, for example, sell bar. I have no connection with them. |
Bazyle | 04/10/2018 22:47:30 |
![]() 6956 forum posts 229 photos | I doubt the original would be solid. The big Elliotts use a hollow cast iron overarm with a hollow alloy drop arm (the bit Neil pictured) The drop arm is hollow to provide an oil reservoir. |
Mike Poole | 04/10/2018 22:54:26 |
![]() 3676 forum posts 82 photos | Posted by Bazyle on 04/10/2018 22:47:30:
I doubt the original would be solid. The big Elliotts use a hollow cast iron overarm with a hollow alloy drop arm (the bit Neil pictured) The drop arm is hollow to provide an oil reservoir. I was able to pick up the overarm for an Adcock and Shiply 1ES and install it so I think it was hollow, it would have been v heavy if solid. mike |
Hopper | 04/10/2018 23:28:09 |
![]() 7881 forum posts 397 photos | Carving that "L" out of a solid lump is madness. Waste of material, time and machine/cutter wear. Much easier to fabricate it from two pieces of 5" x 2" flat bar, or whatever the size is. The end piece could be either bolted and doweled in position, or even welded on before machining. The original would have been cast iron because it's more rigid than steel. But steel would do the job in most cases. You should be able to mill the dovetails to a suitable finish for this purpose. It is not a moving surface under load, like say the ram on a shaper or even the table on a mill. One trick to milling dovetails nice and smooth is to do your finish cuts using only one surface of the cutter at a time. This involves machining to almost final size, then drop the mill table a few thou so the cutter cuts the angled face of the dovetail only for one pass. Then raise the table so the cutter then clears the angled face and cuts only on the flat end face of the cutter and take another pass to machine that face. Yes you end up with a couple of thou in the very corner of the dovetail that is not machined but the mating dovetail should have the matching corner relieved for clearance here so it does not matter. |
Michael Gilligan | 04/10/2018 23:37:50 |
![]() 23121 forum posts 1360 photos | Adam, I feel sure that you are familiar with the machine, but others may find this page useful for reference: **LINK** http://anglo-swiss-tools.co.uk/aciera-f3-milling-machine/ MichaelG.
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Martin W | 05/10/2018 00:09:02 |
940 forum posts 30 photos | The overarm for the F3, see Michael's link above, is quoted to weigh 16kg or in old money 35lbs which is considerably lighter than the weight Jason calculated of 40kg for an L shaped blank. So either I am looking at the wrong thing, Aciera have machined a vast amount off the casting or it is possibly hollow as suggested by other posts above. It is also stored at the bottom of the illustrated tool cabinet as shown in the catalogue, no fork lift in sight Martin W
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JasonB | 05/10/2018 06:55:07 |
![]() 25215 forum posts 3105 photos 1 articles | Three clues to it being hollow and scraped as I said earlier Edited By JasonB on 05/10/2018 06:55:39 Edited By JasonB on 05/10/2018 06:55:58 |
Ian S C | 05/10/2018 09:17:18 |
![]() 7468 forum posts 230 photos | I'd say hand scraped, and hollow for that Jason. If i was making it I'd fabricate from steel plate. Ian S C |
Baldric | 05/10/2018 09:27:59 |
195 forum posts 32 photos | For a foundry within Oxfordshire, there is Swan in Banbury, not used them personally but I know they do castings for preservation. Baldric. |
duncan webster | 05/10/2018 11:00:09 |
5307 forum posts 83 photos | Cast iron is not stiffer than steel, in fact it's Youngs Modulus in tension is considerable less. Considering that the load is put into the overarm via the much smaller arbor it is quite obvious that high tensile steel is not required, as others have said the original would have been cast iron. Using a 'better' grade of steel will not reduce elastic deflection. Making this out of one piece is just making life difficult, Neil's suggestion is far more sensible. I would just make it out of 2 pieces of EN3 (070M20) or S275, but the latter would not machine as well. If the OP really must have it from solid then a plasma cut blank would be a better starting point |
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