I am in need of a 4 mm stainless steel shaft with a center hole of 0.5 mm. I need to fabricate about 100 parts of 4 mm diameter, 30 mm long with o-ring grooves, taper geometries and a center hole of 0.5 mm. While most of the features are doable in a CNC lathe , I think the hole cannot be drilled. Does anyone know where I could find stock material with the hole already there?
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4 mm OD shaft, 30 mm long with 0.5 mm bore 1
- Thread starter gkan
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- #3
Hello CopyPad, thanks for your reply. I dont think they make hypodermic needles with 4 mm OD, that would be cruel to say the least ![[smile]](/data/assets/smilies/smile.gif "[smile] [smile]")
. There are actually some endoscopes with similar dimensions but I dont know how they manage to go down to 0.5 mm bore in that length.
. There are actually some endoscopes with similar dimensions but I dont know how they manage to go down to 0.5 mm bore in that length.Looks like 6 gauge is ~ 5 mm OD, so your size fits within their capabilities.
The ID on that 6 gage is .176" (4.47 mm). I've never been able to find really thick walled tubing like the OP is looking for.
A .5 mm hole 30 mm long is an aspect ratio of 60. I think only ram EDM or lasers can drill something like that and it's going to be slow and expensive.
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A .5 mm hole 30 mm long is an aspect ratio of 60. I think only ram EDM or lasers can drill something like that and it's going to be slow and expensive.
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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.
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- #6
Hi Gkan,
It looks like you have a ratio : Length/ID >10, which means that drilling is very difficult or impossible, in you case L/D=60...
Can you please load a PDF file with tolerances, it will be easier to suggest a process?
What stainless grade are you looking for?
Are you looking for higher volume, in the future?
here are some Ref. ,
Regards,
It looks like you have a ratio : Length/ID >10, which means that drilling is very difficult or impossible, in you case L/D=60...
Can you please load a PDF file with tolerances, it will be easier to suggest a process?
What stainless grade are you looking for?
Are you looking for higher volume, in the future?
here are some Ref. ,
Regards,
MikeHalloran
Mechanical
I suppose you could start with a shorter, larger blank with a bigger center hole and rotary swage it down to the desired ID, then machine the rest of it normally. ... but for 100 pieces, it's hard to amortize the tooling and development costs.
Mike Halloran
Pembroke Pines, FL, USA
Mike Halloran
Pembroke Pines, FL, USA
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- #8
Thank you all for posting.
Dgallup, I have thought of EDM as a last resort if I find nothing else but yeah, I think its going to push production costs through the roof
I am not familiar with the laser technology that can create such a hole, what do you have in mind?
Zinov, ideally I would like to use 316 surgical steel. My pdf drawing is not updated but my tolerances are +/- 0.05 mm for the hole and 0.1 mm for everything else.This is a prototype so, yeah, hopefully I will be looking for higher volumes in the future.
MikeHalloran, thanks, I never thought of that. Is this how needles are made? One would need to design special tooling for that kind of process? Could I get that 0.05 mm tolerance for the hole like that or is it unlikely?
Dgallup, I have thought of EDM as a last resort if I find nothing else but yeah, I think its going to push production costs through the roof
I am not familiar with the laser technology that can create such a hole, what do you have in mind?
Zinov, ideally I would like to use 316 surgical steel. My pdf drawing is not updated but my tolerances are +/- 0.05 mm for the hole and 0.1 mm for everything else.This is a prototype so, yeah, hopefully I will be looking for higher volumes in the future.
MikeHalloran, thanks, I never thought of that. Is this how needles are made? One would need to design special tooling for that kind of process? Could I get that 0.05 mm tolerance for the hole like that or is it unlikely?
racookpe1978
Nuclear
Go the other way around - at least for the prototype 100x parts.
Buy a thick cylinder stiff enough to be drilled: though that is difficult with this small a hole. Assume your can get a drill through at 12 mm dia, maybe 16 mm of stock.
Drill through the 20mm blank, but don't try to get that hole centered "perfectly". Instead, after drilling the 0.5 mm hole first, then use the drilled hole as a center for machining the outside tapers and grooves by the lathe from the outside to match the drilled hole for concentricty.
Buy a thick cylinder stiff enough to be drilled: though that is difficult with this small a hole. Assume your can get a drill through at 12 mm dia, maybe 16 mm of stock.
Drill through the 20mm blank, but don't try to get that hole centered "perfectly". Instead, after drilling the 0.5 mm hole first, then use the drilled hole as a center for machining the outside tapers and grooves by the lathe from the outside to match the drilled hole for concentricty.
racookpe1978
Nuclear
Correction: Drill the a 3.7 or 3.5 mm hole through a 12 mm or 16 mm diameter blank that is 30 mm long. Push through an arbor that is 4.0 mm dia
Reset the blank so the new hole is on center in the lathe with a true 4.0 mm dia hole.
Then machine the outside down to your final shape.
Reset the blank so the new hole is on center in the lathe with a true 4.0 mm dia hole.
Then machine the outside down to your final shape.
I thought maybe Oxford Laser could do it but their limit on aspect ratio is 30:1. They are in the top rank of laser hole drillers, don't know if anybody is going to be able to do it with lasers.
Does the hole need to 0.5 all the way through? Can it be bigger most of the way and step down? Could you start with a piece on tubing and neck it down in sections to restrict the ID?
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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.
Does the hole need to 0.5 all the way through? Can it be bigger most of the way and step down? Could you start with a piece on tubing and neck it down in sections to restrict the ID?
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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.
Compositepro
Chemical
Google "stainless steel capillary tubing". This site has 4mmx1mm.
30:1 limit, 60:1 ration on the part... Align perfectly and laser drill from both ends?
What is the function of the hole? Can it be larger ID and "orificed" at the ends? Interference fit sleeves for short length in both ends to obtain the ID that you want?
To that end, could you use off the shelf 4mm x 1mm tubing that compositepro linked, and sleeve the entire ID? Sleeves could be multiple sections if needed to facilitate the insertion.
What is the function of the hole? Can it be larger ID and "orificed" at the ends? Interference fit sleeves for short length in both ends to obtain the ID that you want?
To that end, could you use off the shelf 4mm x 1mm tubing that compositepro linked, and sleeve the entire ID? Sleeves could be multiple sections if needed to facilitate the insertion.
- Thread starter
- #16
Thank you all for your ideas!
Unfortunately I cannot limit the 0.5 hole to specific areas since there are some o-ring grooves along the shaft that need the extra material to avoid fracture due to excessive stress.
However I found hollow shafts at the diameter I am looking for in that zinov linked, thanks for that!
Unfortunately I cannot limit the 0.5 hole to specific areas since there are some o-ring grooves along the shaft that need the extra material to avoid fracture due to excessive stress.
However I found hollow shafts at the diameter I am looking for in that zinov linked, thanks for that!
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