Dibs-h
Established Member
RussianRouter":1sfh5n97 said:
Ain't there always been one? Don't say I changed it while you were blinking again! :wink:
Help Support UKworkshop.co.uk:
Ain't there always been one? Don't say I changed it while you were blinking again! :wink:
Dibs-h
Established Member
Just spoke to the other firm - hopefully have the quote back late today or the morning. These lot do waterjet cutting so we'll see what the price difference is as well.
It's been confirmed by these lot - lasermarking mild steel is no prob and the depth of the mark is sufficient to just catch your fingernail in it. Aluminium - no chance. Unfortunate - but it's not for the lack of asking.
Almost all the folk have come back confirmed with a few souls not. We'll see how it goes by next week.
I'd suggest you all spend a few mins looking at the Spready - the Detail tab. Ignore the summary one (I'll probably remove that one) and double check your entry. Please ask if anything is unclear.
Dibs
It's been confirmed by these lot - lasermarking mild steel is no prob and the depth of the mark is sufficient to just catch your fingernail in it. Aluminium - no chance. Unfortunate - but it's not for the lack of asking.
Almost all the folk have come back confirmed with a few souls not. We'll see how it goes by next week.
I'd suggest you all spend a few mins looking at the Spready - the Detail tab. Ignore the summary one (I'll probably remove that one) and double check your entry. Please ask if anything is unclear.
Dibs
Dibs-h
Established Member
Josie99":63wmuvh0 said:
How so? Do you plan to laser cut something?
barkwindjammer
Established Member
cant wait to see the pics
RussianRouter
Established Member
barkwindjammer":3czpzkq5 said:
Erm! what tip and what pics?
Reference water jet cutting - did you watch the programme on BBC 2 this evening (Sunday 9.05 pm) on Rolls Royce and making Jet Engines ?
Fantastic programme - if you missed it, wind up your IPlayer and watch it on that. It was an absolute credit to all the guys at RR and also to the film makers. Seriously do not miss it. And it does have a brief clip of water machining.
Rob
Fantastic programme - if you missed it, wind up your IPlayer and watch it on that. It was an absolute credit to all the guys at RR and also to the film makers. Seriously do not miss it. And it does have a brief clip of water machining.
Rob
Dibs-h
Established Member
RussianRouter":g2h55vyv said:
Must be the internet version of radio interference or something.
OldWood":g2h55vyv said:
Thanks Rob - will do. I used to work for a Manufacturing firm that had it's own R&D dept and they had a few waterjet m\c's. Fantastic bits of kit.
That other firm haven't come back to me - will chase them up shortly. Also will be sending everyone in the group a PM with payment details for the deposit.
More importantly - everyone please go over the Detail Tab on the Spreadsheet and ensure your entry is as you want - once the order is placed it'll be a next to impossible to entertain "Oh - I thought......." type of conversations.
http://spreadsheets.google.com/ccc?key= ... McFE&hl=en
Also - as importantly please go over the drawing - I don't think I've missed anything or made an obvious mistake.
The drawing that has actually been quoted against - is identical, but the dashed circle (110mmm dia showing the stepped shoulder) was removed to prevent any confusion.
The one thing I will confirm today is that if the rings\disc are cut to an external dia of 110mm, what will they actually end up at. Just wondering will they drop into our shoulder or require some fettling? Should we have the rings 109.5mm or something or even 109.9mm??
RussianRouter
Established Member
Dibs-h":7e5grbdt said:
Leave as is,even if we have to do some fettling then so be it.
Remember the golden rule in woodwork...." you can take it off but you can't put it back on."
Dibs-h":1c69j3ea said:
That should all depend on the tolerance quoted and the quality of the machining. Specifying a different sized ring is not necessary. The firm you are dealing with should be able to help you here but the stepped hole needs to be specified with a + 0.Xmm, - 0.0mm tolerance and the ring is the reverse, with a + 0.0mm, - 0.Xmm tolerance.
In other words and as an example, the holes could be 110mm +0.1 - 0.0
and the rings could be 110mm + 0.0 - 0.1. If the firm can produce to these tolerances, then they will always fit.
Dibs-h
Established Member
Loz_S":1r2rs5ut said:
Just emailed off for the tolerances. Expect your PM's sometime today.
Dibs-h
Established Member
The cutters have replied - The tolerance up to 3mm thick is +/- 0.1mm above 3mm would be +/- 0.15mm.
Any rethink on the ring\disc size (as they will be from 3mm stock)??
Any rethink on the ring\disc size (as they will be from 3mm stock)??
That doesn't really make much sense. Are they telling you that the plate thickness tolerance is as quoted or that their ability to machine a given dimension is dictated by the material thickness?
Anyway, we may be trying too hard to be too clever. For such a small project (for the machine shop that is) would it not be simpler to ask whoever is in charge to machine the discs for an interference fit (at best) in the plate holes and just leave it up to them to make sure they fit. Otherwise you could end up trying to specify roundness, concentricity, position, flatness and cylindricity!! They may end up just laughing at you or charging twice as much!
If everything is being cut in the same shop just let them know what you want, I'm sure they can suggest a solution without having to try and out guess the quality of their work.
Anyway, we may be trying too hard to be too clever. For such a small project (for the machine shop that is) would it not be simpler to ask whoever is in charge to machine the discs for an interference fit (at best) in the plate holes and just leave it up to them to make sure they fit. Otherwise you could end up trying to specify roundness, concentricity, position, flatness and cylindricity!! They may end up just laughing at you or charging twice as much!
If everything is being cut in the same shop just let them know what you want, I'm sure they can suggest a solution without having to try and out guess the quality of their work.
Dibs-h
Established Member
Loz_S":6gn90t6m said:
Loz_S
The plates\rings\discs are being lasercut, and I would expect the tolerance to alter marginally the thicker the material goes.
The lasercutters are cutting the plates\rings\discs and a separate CNC machine shop will be doing the shoulder. I'll give the machine shop a ring and see what the score is with their setup.
Hope that clears things up.
Perhaps it would be best to get all these cut and then with a random (or something) sampling of ring\disc sizes tell the machine shop to do a shoulder or X mm in dia.
I'll post back the results so to speak.
Dibs-h
Established Member
Update: CNC machine shop - they would cut the shoulder using something like a 50mm dia cutter on a circular path. Tolerance for these lot is +/- 0.01mm.
I'll be sending him a drawing thru and confirm the cost of the shoulder.
I'll be sending him a drawing thru and confirm the cost of the shoulder.
Ahh, laser cutting, that makes sense - obviously wasn't paying attention when that was decided!
If the CNC shop is the last stage in the job then they have the only critical stage in the process so you should be able to get a very smooth interference fit with the rings. Definitely recommend measuring a sample and only then telling the CNC shop what you want.
If the CNC shop is the last stage in the job then they have the only critical stage in the process so you should be able to get a very smooth interference fit with the rings. Definitely recommend measuring a sample and only then telling the CNC shop what you want.
Dibs-h
Established Member
OldWood":30m951sc said:
I think it might not be a bad idea for the rings\discs to be say 0.1mm smaller in diameter than the "hole" they drop into.
We've discussed it before and an interference fit is not what we are aiming for (or that's my recollection) - screwing the discs\rings down was the sensible idea given the proximity of spinning TCT.
If that is the case - i.e. screwing them down - something say 0.1mm or even a little larger would be ok - me thinks anyway. What say the rest?
It would also ensure their are minimal problems afterwards - i.e. very little to no fettling required.
Dibs-h":1p3rthi4 said:
Before anyone else chips in, I don't think it is unsafe to have friction fit rings, just look at any spindle moulder. They normally have multiple interference fit rings, one inside the other. As long as there is no upward force on the ring it is not going to come out. The fence will nearly always be across its widest part, holding it down, anyway.
Seems a little pointless to engineer in an unnecessarily large fit when you are going to the trouble of having something made with such high precision machines.
Just my two eurocents.
Dibs-h
Established Member
Loz_S":ijbfqtfd said:
Depends what your fingers\face are worth I suppose.
You probably are very happy to work with friction rings and be comfortable - but there will (and there are in this group) others at the complete other end of the spectrum. So I would like to hear from the rest of the group.
As for a spindle moulder - very few hobbyists have one, i.e. mostly owned & used by pros and most of them would be using power feeds. So I don't think it's a fair comparison. Ultimately whatever the majority go with is cool - and maybe there's no harm in being safety minded. After all - I don't recall seeing a commercial plate with friction fit rings ever.
Due to the differing tolerances - i.e. 0.15mm (laser cutting) and 0.01mm at the CNC shop, theoretically one could end up with a ring between 99.9 and 100.1 and a hole at between 99.99 and 100.01. So what happens if the rings end up @ 100.1 and the hole ends up @99.99 - or ring @ 100.1 & hole @ 100.01 - would that sort of interference fit mean you could easily pop the ring out by hand? Or would you have to be a bit brutal about it?
