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Any CNC Machine experts here?

Discussion in 'off topic' started by richardg, Mar 20, 2020.

  1. stevec67

    stevec67 pfm Member

    Look up Martins Engineering of Grimsby. Your old part of the world. They used to make parts for Ford. A driveshaft for a Fiesta, I seem to remember. Can they make a clutch slave cylinder? In their sleep.
    richardg likes this.
  2. richardg

    richardg Admonishtrator

    A risk indeed.....I have an old friend from teaching days, they do similar stuff to us - Tyga Performance. Difference is his partner is an engineer, mine's an administrator. They got a cnc machine and have not looked back.
  3. richardg

    richardg Admonishtrator

    Looking now...
  4. russel

    russel ./_dazed_and_confused

    Not sure, I will ask, possibly a bit over your budget new but the figure I quoted was what it would cost to hire, as myself and some fellow nerds were thinking about getting enclosures made for hobby use and at the speed it runs we could get a few done in an hour.
  5. jagdesign

    jagdesign pfm Member

    Datrons are not cheap, but very efficient with ali parts I believe due to their proprietary tooling and ethanol coolant.

    A Haas Mini Mill can be had for sub 40k, I think, and they're capable machines

    A lot of suppliers we work with are very happy with their Hurcos, I have no idea about price though

    My dad used to own a precision engineering business with about 8 CNC mills and 5 lathes - sold the business about 10 years ago now. It's still challenging to compete with far eastern suppliers, although the gap is closing.
  6. richardg

    richardg Admonishtrator

    Thanks, it's true that the price after shipping at about 12% of the value and import duty at 4% makes looking closer to home more feasible. But its not quite there yet for us.

    We sent a part off to 3 different countries for quotes recently. They came back like this.

    France 45 euros per piece
    Thailand 35 euros per piece
    China 20 euros per piece

    The Thai price a year ago, with more favourable currency, would have been the winner, as it would have been close to the Chinese price and this was by Tyga Performance, a friend of mine from when we were teachers there.

    The China price needs 12% and 4% adding on. So 29 euros. France was just too far away at 45. We were prepared to pay 35 in Europe. But it didn't happen. So we ended up in China again.
  7. garyi

    garyi leave blank

    Watch This Old Tony on youtube, you have years and years of practice ahead of you, I think 4 weeks is optimistic.
    richardg likes this.
  8. richardg

    richardg Admonishtrator

    I am really nervous about the slave cylinders....the gap between piston and barrel is about 0.5mm....most suppliers demand tolerance of 0.1mm either way. Unfortunately the seal manufacturers do too....so you need to wait until the slaves come back before speccing the seals, or you could end up with a big gap, which ends up with leaking slaves. And heat resistant seals are about 4 quid each for 200.
  9. Colin Barron

    Colin Barron pfm Member

    Look at
    Are the piston and cylinder not turned and then ground. Maybe the piston needs to be centreless ground and the cylinder in some sort of chuck and internally ground. Inspection is by air column gauge i would have thought checks on diameter, roundness and taper of both the piston and cylinder. Is the bore honed? The seal diameter will need to be concentric with the cylinder bore. If you obtain the seal drawings and look at the hole tolerance for fitting and the piston tolerance diameter, roundness and surface roughness so that it does not damage the rubber. This is safety critical automotive gear,it needs to be properly designed.
  10. richardg

    richardg Admonishtrator

    I don't think any are. Certainly not ours or our competition....and our stuff is better than OEM in some cases. EG KTM customers buy ours for bikes less than 3 years old because the KTM ones keep leaking.
  11. sq225917

    sq225917 Bit of this, bit of that

    Theres usually good clearance between cylinder and piston, cylinder bore isnt polished, piston could be phenolic, stainless or sometimes alloy in low heat build up applications. Usually stainless in 250cc and above bikes.

    The outer seal is just a scraper, it's the inner square rings that holds the oil back. They're remarkably rough looking actually. Go to fancy race brakes and you'll get polished pistons with low friction teflon coatings.

    Simon (ex Kawasaki mechanic)
  12. richardg

    richardg Admonishtrator

    right....the oem ones have lumpy bore surfaces in many cases. no wonder the seals don't last. also most oem ones use O rings and we use grooved seals.
  13. Colin Barron

    Colin Barron pfm Member

    Does your seal manufacturer not specify size, roundness and surface roughness etc.
  14. richardg

    richardg Admonishtrator

    They're not round, Colin, they are grooved piston seals, like this:


    We have been using Martins Rubber in UK. But due to high price and lack of consultancy when ordering (they want a highly specced order, we want help determining the best seal for the job and we want them to measure the pistons and tell us what they think the size should be), we left them and found a more collaborative supplier in China. Thing is we worry about being cheated on quality of rubber in China. It must be FKM rubber to cope wiht brake fluid and engine heat at the same time. FKM is really expensive. As I said we are paying 4 quid with Martins. A normal O ring of the same size costs about 20p
  15. sq225917

    sq225917 Bit of this, bit of that

    Sounds like you need an engineer with experience on your staff.
    AndyPW and Barrymagrec like this.
  16. russel

    russel ./_dazed_and_confused

    Ethanol cooling is one of the reasons they bought it, i was told if you want high tool speed you must have coolant and normal coolant is messy, requires constant recycling to keep it free from mould and only becomes economic if you have a very high utilisation rate.
  17. stevec67

    stevec67 pfm Member

    You can get long life coolant that doesn't go off. The old suds tanks do stink once the bugs start growing. It's a water oil emulsion, it's going to go off.

    Small scale engineers mix oil, water and washing up liquid in a bottle, then they just brush it on the work as it cuts. But they don't run flat out all day.
  18. gintonic

    gintonic 50 shades of grey pussy cats

    that was the view i was coming to. It really sounded like the team doesn't really have the engineering knowledge or experience to talk knowledgeably with suppliers
  19. sq225917

    sq225917 Bit of this, bit of that

    Yup, easy enough to hire some brains in, you just need a pneumatics guy for a week to define your surface tolerances, finishes and seal specs. In the scheme of things it's not mega precision, +/- 5 100ths rather than microns.

    I'd imagine the guys at Hope Components in Barnoldswick could be helpful, UKs largest push bike disc brake manufacturer as regards specs and seals.
  20. richardg

    richardg Admonishtrator

    for sure! We have me: motorbikes, internet, fulfilment, products. We have Gilles: accounts, admin, phone (tri-lingual), blue-sky thinking, lunch. We defo could do with someone that is an engineer.

    A friend was just saying, wait 3 months and there will be some CNC companies going for a song...

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