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Re: grade 5 drilling question

Posted: Fri Sep 05, 2014 4:35 pm
by Kuraki
wp6529 wrote:
4. Coolant pressure-fed drill bits, specified to work with Ti by the manufacturer, work the best and eliminate the need to peck. The Guhrrng RT100 VA, available from MSC for under $100, looked good to me and I could probably rig a low pressure coolant feed to it but, without high pressure, I suspect pecking would still be necessary to keep the coolant flowing so I doubt I'll invest.
I keep thinking that a cheap $99 Harbor Freight electric pressure washer would make a useable pump for coolant fed tooling...
In my Google Drive I have a number of PDFs about a number of different manufacturing, gunsmithing, design stuff. One of them is Bill Webbs Rifling Machine Supplement. There's some information in there about a high pressure oil pump system for gun drilling that may or may not be helpful.

Feel free: https://drive.google.com/folderview?id= ... sp=sharing

Re: grade 5 drilling question

Posted: Fri Sep 05, 2014 5:32 pm
by calinb
john.t.little1 wrote:I had no Issue but again was slow 115rpm and flood coolant and the inserts I used were uncoated.
Yup--from what I've read, 115 rpm sounds about right for a 1/2" dia. hole using HSS/cobalt steel (15 SFM)! It's clear from reports on various forums that most people try to spin drill bits too fast in Ti.

Inserts? What kind of tooling? I'm just trying to figure out how to drill an initial hole big enough for a small boring bar without destroying too much grade 5 bar and bits!

Thanks!

Re: grade 5 drilling question

Posted: Fri Sep 05, 2014 5:38 pm
by calinb
wp6529 wrote: I keep thinking that a cheap $99 Harbor Freight electric pressure washer would make a useable pump for coolant fed tooling...
I was thinking along those lines too--or maybe a small airless paint sprayer, which have pumps in the pressure range we'd need.

However, I don't think the pump is the most difficult part of realizing a cheap pressure feed system. It would probably still require buying sealed ER collets (or at least one :)) and a chuck, unless you REALLY want to get into a big design and fabrication project, and the rest of the plumbing would still be challenging. But maybe you have some clever quick and dirty design ideas for that part too.

Re: grade 5 drilling question

Posted: Fri Sep 05, 2014 5:55 pm
by L1A1Rocker
wp6529 wrote:
4. Coolant pressure-fed drill bits, specified to work with Ti by the manufacturer, work the best and eliminate the need to peck. The Guhrrng RT100 VA, available from MSC for under $100, looked good to me and I could probably rig a low pressure coolant feed to it but, without high pressure, I suspect pecking would still be necessary to keep the coolant flowing so I doubt I'll invest.
I keep thinking that a cheap $99 Harbor Freight electric pressure washer would make a useable pump for coolant fed tooling...
Actually their cheep fountain pump with a 5gl bucket and assorted plumbing can make a pretty good flood system.

Re: grade 5 drilling question

Posted: Fri Sep 05, 2014 6:57 pm
by john.t.little1
calinb wrote:
john.t.little1 wrote:I had no Issue but again was slow 115rpm and flood coolant and the inserts I used were uncoated.
Yup--from what I've read, 115 rpm sounds about right for a 1/2" dia. hole using HSS/cobalt steel (15 SFM)! It's clear from reports on various forums that most people try to spin drill bits too fast in Ti.

Inserts? What kind of tooling? I'm just trying to figure out how to drill an initial hole big enough for a small boring bar without destroying too much grade 5 bar and bits!

Thanks!
Inserts I used were vnmg and usually drilled .5 hole and bored using solid carbide micro100 boring bars

Re: grade 5 drilling question

Posted: Fri Sep 05, 2014 6:59 pm
by john.t.little1
L1A1Rocker wrote:
wp6529 wrote:
4. Coolant pressure-fed drill bits, specified to work with Ti by the manufacturer, work the best and eliminate the need to peck. The Guhrrng RT100 VA, available from MSC for under $100, looked good to me and I could probably rig a low pressure coolant feed to it but, without high pressure, I suspect pecking would still be necessary to keep the coolant flowing so I doubt I'll invest.
I keep thinking that a cheap $99 Harbor Freight electric pressure washer would make a useable pump for coolant fed tooling...
Actually their cheep fountain pump with a 5gl bucket and assorted plumbing can make a pretty good flood system.
That's what I used I had to drill a hole in my chip pan put a drain piece in and pipe to the bucket.

Re: grade 5 drilling question

Posted: Fri Sep 05, 2014 7:30 pm
by maccrazy2
My lathe goes from 90rpm to 240 so I between is not an option untill I upgrade to a vfd.
Thanks for all the info posted. I was trying to get this done with existing tooling since it is not going to be a regular material for me to work with. I did see a video of an indexable cutter gun drill that punched a large hole in one shot. Just not cost effective for one project.
I have a 3/4 gun drill from drill masters but did not want to risk damaging the cutting edge as I need it for my normal work.

Re: grade 5 drilling question

Posted: Fri Sep 05, 2014 8:08 pm
by calinb
Kuraki wrote:[
In my Google Drive I have a number of PDFs about a number of different manufacturing, gunsmithing, design stuff. One of them is Bill Webbs Rifling Machine Supplement. There's some information in there about a high pressure oil pump system for gun drilling that may or may not be helpful.

Feel free: https://drive.google.com/folderview?id= ... sp=sharing
Wow--thanks! Good stuff, regardless, and I'll read it and see what I can glean from it. Makes me want to make a gun drilling machine!

Re: grade 5 drilling question

Posted: Fri Sep 05, 2014 8:37 pm
by calinb
maccrazy2 wrote:My lathe goes from 90rpm to 240 so I between is not an option untill I upgrade to a vfd.
Working the problem "backwards" from 90 rpm and 15 SFM I get a 41/64" drill bit. 90 rpm yields 11.8 SFM with a 1/2" drill bit and it seems to me that would be close enough to work well too.

The "Drilling" table on page 5 here is where I read 15 SFM for M42 drilling:

http://www.mhims.co.uk/titanium-bible.pdf

I've read a bunch of 20 SFM recommendations in forum posts so 15 just might be ideal, though it probably seems slow to many people, due to their experience with other metals. Now I see that the table actually recommends 20 SFM for annealed Ti, which is probably what's mostly sold on Ebay. Either way, slow is the key.
maccrazy2 wrote:I also have an indexable chamfering bit that will cut a 60 deg chamfer from the 1/4 hole out to 3/4. It shoots ribbons about 1/2 wide like it is aluminum. Although I can hear the machine lugging a little more. Only did that one time just to see if I could.
That's good to know and I was thinking about trying one of those tools too. 240 rpm and a 1/4" drill bit is 15.7 SFM and that should be just about perfect to get your indexable chamfering tool cutting those ribbons afterwards.

Re: grade 5 drilling question

Posted: Sat Sep 06, 2014 12:06 am
by wp6529
Lots of good docs, thank you!