Runout drilling 2mm hole

[Men IfrParticipant @menifr84251]

I rang RDG tools and they say the accuracy of their collets is 0.012mm so if true even if the set I get the s all at max tolerance that is a big improvement on the 0.07-0.09 I have now so think I will give them a go… Every little helps and if I’m reaming a hole with 0.1mm runout its not going to come out at 2.0mm is it. Thanks for the info on the D tools very useful, for now though the plan is better collets, drill to 1.9 then ream to 2mm.

[norman royds 2Participant @normanroyds2]

I think procedure is the problem I would proceed as followed, by drilling a smaller drill hole then try 2mm steel to the hole and if that dos not fit try. until you find the one that does with number drills imperial & metric you find the one fits or buy a 2mm reamer. aluminium is different the taper reamer would be a good idea .well who am I norman the mentor for john hamer the builder of Samantha the .paddle steamer and reason for the reply one night john and I were working on the gorgon engine john did not have the right drill or reamer for the bearings I would bring them the next visit .well this is where the story begins when I returned with the drills and reamer, john had done the job to my surprise he told me that he drilled pilot holes then followed with the drill he thought would do the job and guess what? the fit was perfect not one but all four. I said your kidding me.to all the engineers out ther is that lucky or not PS I am more at ease on the milling machine &lathe than writing norman royds

[JasonBModerator @jasonb]

I Thought you said the collet holder had 0.01mm run out in your first post?

What is the spindle run out

[Men IfrParticipant @menifr84251]

Hi Jason,

Yes I think the collet holder has 0.01 run-out by measuring the lower inside surface i.e. where a collet fits into.

I though that was good given the collets add 0.07-0.08ish?

I've measured the spindle (bottom of the inside surface) just now at 1/2 a division on my DTI so 0.005 – I'm thinking that's quite good?

This is the video of the total run-out. https://youtu.be/B4gPL9fLydc

[Mike PooleParticipant @mikepoole82104]

Floating holders can be used to avoid any runout affecting the reamed size.

Mike

[JohnFParticipant @johnf59703]

Men Ifr, Regarding RDG collets etc, some years back I purchased a collet holder for my Myford and a set of ER35 collets, I am very satisfied with them and the runout is well within the limits they have quoted you, mine are in the order of less than 0.0004" TIR [don't do mm but its 0.01016mm] I have not tested every collet but whenever the need arose to check concentricity these figures have been found.

The holder was indeed less than 0.0002" TIR when mounted, better than I would have expected for the price.

No connection with RDG other than a customer.

[Men IfrParticipant @menifr84251]

Well.. the plot thickens I retested the run-out on the collet holder and got 0.07mm – a huge increase from the 0.01 I think I got last time. I then tried indexing the holder and get 0.015 in the best position and 0.07 in the worst very odd but I have marked it up so will put in indexed in the future..

Still waiting for my 1.9mm ground drill bit and 2mm reamer to arrive – and I will probably buy the RDG collets.

Since I'm going to need to centre drill every hole first what are people's thoughts about holding a drill bit on the twist section so only a few mm protude and use that to make the centre drilling faster?

[JasonBModerator @jasonb]

I was always taught not to hold a drill by its flutes.

It is not just the shortness of teh ctr drill that matters but the fact they have a smaller "flat" bit where the flutes meet, Better than a ctr drill is a spotting drill which will come to even more of a point plus not having the small dia end is less likely to snap.

Split point drills are better at self locating than a standard drill but for small sizes or where location really matters I still like to spot first. If you are in a hurry then think about stub drills which are shorter., something like a Dormer A022 series will also have the split point.

[Tony Pratt 1Participant @tonypratt1]

Word to the wise, use a spotting drill.

Tony

[Men IfrParticipant @menifr84251]

Posted by Tony Pratt 1 on 10/11/2017 17:13:18:

Word to the wise, use a spotting drill.

Tony

I never knew I had so little knowledge about drilling a hole… I looked at https://www.cnccookbook.com/when-to-use-a-spot-drill/ and it has great info on spotting drills, yes they will be much better for centering than the 'centre bits' I had been using.

Only problem now is can I get the 90p part without paying £5 postage – I need to find a machine shop supplier near me, I've seen Cromwells in Coventry 10 miles away but would be useful to find something in Warwick – any ideas how I do that? I've Googled machine shop suppliers but can't see anything (at least in Warwick)

[JasonBModerator @jasonb]

90p seems very cheap for a spotting drill, save yourself more hasle and get a decent one, I usually use the KEO ones.

Try searching "engineering supplies" as machine shop is more an American term.

[Anonymous]

Out of interest I've just put a 2mm drill through a bit of 6mm alumimium plate from the scrap bin. No marking out, no spot drilling, just drill straight through.

The shank of a #47 drill (measures 1.96mm) goes through with a very slight wobble. The shank of a #46 drill (measures 2.04mm) will not go through. So I'd estimate the hole is probably around 2±0.02mm. That's plus or minus a thou. So if the OPs results are different either the drill or setup is wrong. And if the setup is wrong I doubt drilling and then reaming is going to help much.

Oh, yes, the drill was a Dormer 4 facet jobbing drill.

Andrew

[not done it yetParticipant @notdoneityet]

Posted by Men Ifr on 09/11/2017 12:56:10:
I rang RDG tools and they say the accuracy of their collets is 0.012mm so if true even if the set I get the s all at max tolerance that is a big improvement on the 0.07-0.09 I have now so think I will give them a go… Every little helps and if I'm reaming a hole with 0.1mm runout its not going to come out at 2.0mm is it. Thanks for the info on the D tools very useful, for now though the plan is better collets, drill to 1.9 then ream to 2mm.

Have you changed the jaws into different positions? Can make a big difference which slot jaw no. 1 is fitted into.

Is the chuck running concentric to the spindle, if you have a back plate? Or is/are the register(s) clear of any burrs or contamination? Even the spindle may have some run out.

What I am saying is that it may not be the chuck which is at fault.

Also, the run out quoted by RDG was for the collets? The whole system may not be as good as that (should be better than 7 thou, mind!).

[Men IfrParticipant @menifr84251]

Posted by JasonB on 10/11/2017 18:31:48:

90p seems very cheap for a spotting drill, save yourself more hasle and get a decent one, I usually use the KEO ones.

Try searching "engineering supplies" as machine shop is more an American term.

This is whet I was looking at: https://www.cromwell.co.uk/shop/cutting-tools/spotting-drills-hss-and-carbide/hss-135%C2%B0-straight-shank-scd-stub-centring-drills-metric/f/11739?query=spotting%20drill

[Men IfrParticipant @menifr84251]

Sorry should be what I was looking at..

[Men IfrParticipant @menifr84251]

Posted by not done it yet on 10/11/2017 22:16:58:

Posted by Men Ifr on 09/11/2017 12:56:10:
I rang RDG tools and they say the accuracy of their collets is 0.012mm so if true even if the set I get the s all at max tolerance that is a big improvement on the 0.07-0.09 I have now so think I will give them a go… Every little helps and if I'm reaming a hole with 0.1mm runout its not going to come out at 2.0mm is it. Thanks for the info on the D tools very useful, for now though the plan is better collets, drill to 1.9 then ream to 2mm.

Have you changed the jaws into different positions? Can make a big difference which slot jaw no. 1 is fitted into.

Is the chuck running concentric to the spindle, if you have a back plate? Or is/are the register(s) clear of any burrs or contamination? Even the spindle may have some run out.

What I am saying is that it may not be the chuck which is at fault.

Also, the run out quoted by RDG was for the collets? The whole system may not be as good as that (should be better than 7 thou, mind!).

No jaw positions this was with ER20 collets. I did measure my drill out of interest and it had ~0.07 run-out which seems 'normal' for a 3 jaw chuck and is about the same as the collet set-up. if changing jaws can make a difference I may try it as I'm measuring run-out on everything now!

Yes RDG quotes run-out on the collets but I measures 0.01-0.015 on the inside surface of the collet holder (when indexed right) so that seems reasonable.

[Chris TriceParticipant @christrice43267]

Gently tap the drill shaft near to the collet as it's rotating. I find this often seats everything where it should be before tightening it a little more. In theory, it shouldn't make a difference. In practice, it often does.

[Chris TriceParticipant @christrice43267]

… or use the tail end of a boring tool and advance it until it just touches the shaft of the drill near the collet in the same way that you can use a boring bar to steady a drill bit to drill centrally without resorting to a centre drill. Again, in theory it shouldn't make a difference but in practice it sometimes does.

[JasonBModerator @jasonb]

Posted by Men Ifr on 10/11/2017 23:01:07:

Posted by JasonB on 10/11/2017 18:31:48:

90p seems very cheap for a spotting drill, save yourself more hasle and get a decent one, I usually use the KEO ones.

 

Try searching "engineering supplies" as machine shop is more an American term.

This is whet I was looking at: https://www.cromwell.co.uk/shop/cutting-tools/spotting-drills-hss-and-carbide/hss-135%C2%B0-straight-shank-scd-stub-centring-drills-metric/f/11739?query=spotting%20drill

 

 

That is not a spotting drill, this is not tried the sherwood but as you were looking at Cromewll's I used one of theirs to link to.

This is a KEO one though they are imperial, don't be put off by ythe photos they actually ;look like the Cromwell ones at 1/8" x 1.25"

Edited By JasonB on 11/11/2017 07:30:52

[Men IfrParticipant @menifr84251]

The ER20 collets arrived from RDG and to my dismay the 2mm hole does not look to be in the centre of the collet (where the split lines cross) this is what I could see with the chinese one I had before. – Maybe it is my imagination but I don't think so. They do seem to be machined/ground though and the chinese ones aren't but you can also see some manufacturing errors.

Anyway 1st test I check the run-out setup the same as the video I posted earlier and I get 0.045 – so only slightly better than the Chinese one.

I'll go and measure some-more and re-check the collet holder in case that's a long way out…

What's the consesus on oil on the collet and tightening torque – I'm giving a reasonable nip with a 300mm spanner I may try a few 'tightnesses' and see if things seem to get better or worse.

Only 1 more thing – I'm using a drill bit and measuring on the shank, I'm assuming that should be a reasonable method. – also it means this is likely the best possible result as the run-out is likely to get worse further away from the collet (i.e. at a drill bit tip where it actually matters…)

 

 

 

Edited By Men Ifr on 14/11/2017 17:33:52

[EmgeeParticipant @emgee]

Wonder if you are using a drill shank the same size as the maximum collet capacity and not oversize.
Don't expect a 2mm collet to close less than 1.5mm and retain any good concentricity, 1.5-1.0mm collets are available.

My collet tapers and threads get a very light coat of oil before fitting the tool.

Emgee

[Men IfrParticipant @menifr84251]

Typically I've been measuring like for like i.e. 2mm collet 2mm drill bit shank.

I've been getting 0.045 – 0.07 across the set so far. I'll ring them in the morning to see what they say.

I ordered a drill chuck plus abour at the same time – I'll measure that – I wouldn't expect it to be more accurate but given the poor results from the collets you never know.

The other possibility is even through I can measure the collet holder at + 0.01 maybe the way it holds the collets makes them inaccurate..?

[Author]

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