Help drilling holes on lathe - swage die blanks

[scrapcan]

I am building skills with the lathe but seem to have a hard time with drilling using the tailstock. My projects are 1.5 to 2 inch long swage die blanks. I am trying to drill the hole for ejector rod and I get pretty bad alignment.

It may be improperly sharpened bits, wrong type of bit, or ???

any help for a newbie?

[shaune509]

first did you center drill the material, the center drill is short and if the tailstock is alianed with the head stock will give a near true start for the larger drills.
yes the drills need to be ground correctly or they can pull off center,
i have found that taking several step cuts up to the near finished size instead of one bit is easer to keep true.
yoe will want to ream or hone to your final sixe as drills tend to cut oversized.
also keep your tailstock as short as posable to the cut to reduce any flex and alignnment errors.
shaune

[scrapcan]

Yep used the correct size center drill. The headstock and tailstock appear to be in alignment using two centers or the method of test cuts on a bar.

Would one be better off with 118 or 135 degree or split point drills? Doe sit make a difference if one uses machine length, standard, or long bits?

What about cutting fluid? I am using machine length HSS drills. They are new USA made drills in fractional or number sizes.

Other than learning the parting off trick this has been the big hurdle so far.

[blaser.306]

Yes it makes a difference ! The shorter the bit you use the less deflection (wnder ) you are likely to experience . Thus the stubby center drill ! Just my opinion as I am not a machinist !!!

[machinisttx]

What material are you making the blanks from? What cutting fluid are you using? What size drill?

[scb]

I didn't see anyone mention facing the part first. If the face isn't true you won't get a straight hole.

[hickstick_10]

Are you drilling from the other side to the previous hole?

And are you using a 3 jaw chuck to accomplish this? [smilie=b:

[jmsj]

manleyjt,
machinisttx asks some important questions. I keep a drilling speed chart handy in the shop, correct or close to correct speed makes all the difference. I like to use 135* bits and yes correctly sharpened bits make a big difference. I am not that great at hand sharpening bits, I use a "Drill Doctor" and it works good for me.
Let us know, jmsj

[scrapcan]

Ok a bit more info.

I am using a SB heavy 10 with 5c collets in the spindle nose. Using machine length bits in the tailstock. I have tried bit sized from 1/8 to 1/4 inch. I am suing A2 tool steel from enco. cutting fluid is mobile (not sure which one), rigid sulphurized, tap magic, and a few other options ( such as #2 diesel, kerosene, parrafin, 90W non detergent gear oil) I know but making chips is a learning process and I did a few things to learn why people don't do it.

I was drilling the pilot all the way thru on faced blank. I tried to drill half way turn around and drill other side, but that did not work too well either.

I am beginning to think I just need to get a good drill sharpener or jig and re point all the drill bits. Should I look at getting a sharpener/jig that will allow doing split points for does it matter that much?

I would not have thought I would be dogged on this step, but it seems to be my hurdle at the moment.

[garandsrus]

How bad is the alignment? How are you measuring it?

John

[scrapcan]

John,

some tries are not bad, but far enough off that alignment of top punch in the csp-1 press is an issue. Some are bad enough you can see it with the naked eye.

alignment of the lathe has been tested by me, who remember is a novice, by aligning headstock and tailstock using two centers. And then by turning a 10 inch to 1ft bar at various spots and comparing diameters.

I really think my issue at this point is the drill point geometry, but it could be something else.

The length of blank die is based on a couple of sets of lswc corbin dies that came with the csp-1 when it came to me. I may try just making some more random interestign pieces to see if I can get this drilling thing sorted out. I will keep watching the thread and updating on my end.

[Buckshot]

..............You're not trying to drill all the way through are you? You don't need to if you are. Are you sure your drill chuck is holding the bit co-axial, or that the chuck's morse taper in the tailstock has it pointing the right way? I long ago broke down and bought an Albrecht integral shank chuck for the tailstock on my lathe. It was on sale for a bit less then $300.

http://www.fototime.com/4E6A51927B56C9E/standard.jpg

The ejector pin in this swage die I made for my Walnut Hill is a #30 (.1285") drill bit shank (6" aircraft bit) I used to drill the hole after starting it, and was then cut off to use as the ejector pin. The bits I use are 135º split point's, BTW. Chuck up a drill or reamer blank and run a TI on it's top and it should show up any cattywhumpus tendancies in the chuck.

However, usually to have a hole wander is a bit issue, but you're only going an inch or so, right? Pushing a slender bit can have it wander also. A machine length bit shouldn't have an opportunity to wander to any great extent, due to being short and rigid. Does this happen with ALL the bits?

............Buckshot

[Bret4207]

I learned to grind drill bit by hand and a drill gauge. Then I got a Drill Doctor, way back when they were over $250.00. Get one, they'll get you even cutting lips and that's where you need to start. Read the directions and watch the video and learn to hold the collet with your left hand while tightening with your right. That plastic flexes and will throw things off if you don't. It'll let you split point too. Then you can either hone or grind the bit to finish it if you find it doesn't cut right.

Also, any vibration in the lathe will tend to throw the bit off. I don't know why, but it seems to. So watch that.

Another note- all of us using those Chiwanese drills- most of them are harder than heck and brittle. Sharpen them BEFORE using them and they'll work a lot better. They ain't perfect, but I can't afford perfect anymore.

[scrapcan]

Bret and Rick,

Thanks for the advice. I have a couple issues, but the biggie i think is bit geometry, I will work on that as that is easily rectified (famous last words), I may have access to a drill and toolbit grinder here locally.

I do have some vibration due to reworked teeth on the end gear train. Not much I can do with that at the moment, but try to keep cutting speed and feed in the correct range. I have some round bit blanks and will chuck one up and see what kind of runout I am seeing.

I may also have an issue with the tailstock barrel and the chuck adapter/morse stub. I am going to try to make a drill chuck adapter that I can put in a boring bar holder and see if that helps.

If I try this is there any reason not to try to run with the power ongitudinal feed to the apron?

I am glad you guys are out there for me to ask questions of as there are very few resources here locally. One of the best machinists inteh area quit and started being a framing/finish carpenter as he could make more money doing that than being a 70 year old machinist. Our local community college sold the machine tools for scrap and made the shop into an excercise bike room. Most of our local gunsmiths are parts changers or ship to repair center types, so they are no help. Really bad situation in my estimation.

[Bret4207]

Bearing in mind that my lathe is an ancient worn out Altlas 6", I have not had good luck using the feed when drilling or boring. All it take is a hard spot or some heat to really goof things up.

[machinisttx]

Ok a bit more info.

I am using a SB heavy 10 with 5c collets in the spindle nose. Using machine length bits in the tailstock. I have tried bit sized from 1/8 to 1/4 inch. I am suing A2 tool steel from enco. cutting fluid is mobile (not sure which one), rigid sulphurized, tap magic, and a few other options ( such as #2 diesel, kerosene, parrafin, 90W non detergent gear oil) I know but making chips is a learning process and I did a few things to learn why people don't do it.

I was drilling the pilot all the way thru on faced blank. I tried to drill half way turn around and drill other side, but that did not work too well either.

I am beginning to think I just need to get a good drill sharpener or jig and re point all the drill bits. Should I look at getting a sharpener/jig that will allow doing split points for does it matter that much?

I would not have thought I would be dogged on this step, but it seems to be my hurdle at the moment.

I have cut/drilled/turned/bored/milled/jig ground/flat ground/etc. a lot of A2 steel. I don't remember having any really significant issues with getting straight holes, but I had sharp drills(either new or resharpened by me).

I don't remember what I used for sfm, but somewhere around 50-60 sounds right. Since I have a Heavy Ten, I know that puts the rpm out of what you're able to achieve with the machine. Run it around 900-1K rpm and use short(.125 or less preferably) peck depths to clear the chips. Keep the drill well coated with oil(I happen to like sulfurized oil). Also be careful about how much pressure you're using to feed the drill. Remember that you're using a threads to feed that drill in, and threads generate a lot of force. If you apply too much force, you will either break drills or get deflection.

If you dry to drill too deep without clearing chips, you'll wind up generating a lot of heat, which will oversize the hole and cause the drill to wander. Keeping it well lubed will also cut down on the heat. If you want the hole to be absolutely true and straight, you really need to bore the hole after drilling, assuming the hole is large enough for a micro bar.

[Buckshot]

.............manleyjt, again, you're not attempting to drill the full length of the die body are you? Also, if your bits are coming from the hardware store and are even made in the good ole USA ............they're STILL hardware store bits :-) They're certainly good enough for stuff a person will likely do around the house or in the garage, but how many will be wanting to stick one through 1.5 - 2.5" of steel?

I really like parabolics. Most regular fluted bits will penetrate maybe 2-3 times their OD and then the flutes pack up and the bit is being stressed, finish is being messed up, and it isn't doing the hole any good either.

http://www.fototime.com/6A8B894E243D50D/standard.jpg http://www.fototime.com/9AFEDA0136AFB4C/standard.jpg

This parabolic 1/4" bit (Guhring USA made) has been stuck through I don't know how many FEET of steel. If it needs a hole, this is the one to start it (after centerdrilling) unless it needs to be less then 1/4" :-) It's a 135º split point. It's main reason for being is to start holes for step drilling, and as shown in the right photo it's main use is in die bodies. It'll pierce the 1.56" length with one backout.

A similar (but jobber length) is: Parabolic - Type: Jobber Size: 0.2500 In Price: $26.81 ea Mfr: Guhring Mfr #: 9006580063500

Four or five years back on E-Bay I was high bidder on a plastic cassette of 10 of these 1/4" bits. I forget the price as it was (to me) fairly unremarkable for ten 1/4" bits. However they performed unlike anything I'd ever experienced before, so I started to research them. HOLY SMOKE! I think I paid for all of them what one would have cost. I'm right now only using the 3rd bit out of that pack!

All that aside, even the best bit in the world can't do it's job if there is an alignment issue, which can be in the tailstock (offset), tailstock bore, worn tailstock ram, scabbed up morse taper in the ram, or chuck issues. If there are no problems here, most any drill bit should be able to deliver a fairly straight hole of 4-5 times it's OD unless it's radically poorly ground.

..............Buckshot

[machinisttx]

I have drilled I don't know how many holes with standard twist drills, a lot of them being more than 3x diameter deep. A HSS drill is going to wander some, it's inevitable. Split points don't really change that in my experience, they just reduce the cutting pressure required to get them through the material.

[Cap'n Morgan]

When using a center drill don't overdo it! Just a small spot is enough. Center drills are not meant to be used to start drills, but to form a "bearing" to support the part between centers when turning or grinding.

If you want the hole to run really true, make the finish cut on the outside of part after the hole is drilled. Use a live center in the tailstock, and a solid center in the chuck - you can use a any piece of round stock for center, and turn a 60 degree point on it after clamping it in the chuck for minimum run-out. Tighten the spindle enough so that the part won't slip under a light cut.

[scrapcan]

Cool beans guys, I appreciate the help. I was at first trying to dril thru. When the deviation showed up in my results I changed that pronto and read alot about how to do it properly. not loading the flutes, not too much pressure, keeping the bit and work peice cool and lubed with cutting oil, etc...

What I have found is the lowely drill bit is poorly understood by most and it is not so lowly afterall.

I don't have a lever tailstock, but it may be on the list of wants as it would make the shaollow pecking method much easier and quicker. I bought good drill bits the number set is clevland and is NOS from the 50's, the fractional set is mixed NOS from 50's to 70's. I am still looking for the letter set. All are HSS.

But i can be blunt that my hand sharpening skills for drills leaves a lot to be desired, I use a guage and keep things cool, but it takes me a bit to make sure I get the geometry correct. I think drill sharpening should be one of those things they start to teach kids at about 5 years of age.

Anyway I will be putting the shared info to use.

I will continue on my learning curve and report back. I will get there, but may need more help form all of you.

[Char-Gar]

I have not had any problems drill holes on my little Logan. I just feed the bit with the tailstock handwheel and use lots of lubricant. I don't try and horse the bit through, but just take my time and let the machine do it's thing.

[Beekeeper]

Manleyjt,
I grew up in a machine shop (literally) and spent a lot of time running a lathe when younger. Was never of the class of Buckshot as my desires ran in a diferent direction.

One thing I learned from my Dad was to turn the tool holder around and use the back or butt to touch the drill during the first 1/2 to 3/4 inch of the hole and it will help to keep the drill on the straight and narrow.

Not much of a tip but maybe it will help.


Jim

[scrapcan]

Beekeeper,

I have been playing with that technique as it is mentioned in all of my books on lathe operation. I am finding that it works better with the lantern style tool post and holders compared to the aloris style QC toolpost and holders. Actually I am getting ready to gring a HSS blank about 1/2 inch square that will fit in the axa qc tool holder to try to get the angel right to use a s a backer.

Thanks for bringing this up in the thread.

[machinisttx]

Cool beans guys, I appreciate the help. I was at first trying to dril thru. When the deviation showed up in my results I changed that pronto and read alot about how to do it properly. not loading the flutes, not too much pressure, keeping the bit and work peice cool and lubed with cutting oil, etc...

What I have found is the lowely drill bit is poorly understood by most and it is not so lowly afterall.

I don't have a lever tailstock, but it may be on the list of wants as it would make the shaollow pecking method much easier and quicker. I bought good drill bits the number set is clevland and is NOS from the 50's, the fractional set is mixed NOS from 50's to 70's. I am still looking for the letter set. All are HSS.

But i can be blunt that my hand sharpening skills for drills leaves a lot to be desired, I use a guage and keep things cool, but it takes me a bit to make sure I get the geometry correct. I think drill sharpening should be one of those things they start to teach kids at about 5 years of age.

Anyway I will be putting the shared info to use.

I will continue on my learning curve and report back. I will get there, but may need more help form all of you.

Don't try to follow the same relief grind as was originally on the drill. I've seen a couple of guys who were fair at it, but it's not really necessary. As long as your grinding wheel surface is true, get your angle correct, and then pull straight up with a slight twist just before the wheel leaves the drill. If you do it correctly, you'll have all the relief you need, while still having enough material to support the cutting edge.

[scrapcan]

machinisttx,

Thanks for the tip. I am doing ok wiht the proper angle. I get a nice straight point on most bits.

What wheels do you recommend for drills? I need ot geta new one as I am nearing the useful diameter of the one I am using. And in the process of gettign a replacement I might aswell learn on that topic also.

[theperfessor]

Don't know if any of what I'm about to share will help you but here goes. I've tried all kinds of ways to get a concentric drilled hole using a lathe.

1. Bought a couple of really stubby screw machine drills that have the same point angle as the drills I use. These seem to work better than a regular center drill. A center drill usually has a 60* point, while a drill has a 118* or 135* point. When the drill first encounters the material it hits the edge of the hole before the center, so instead of being guided by the drill point center it is being guided by the lips. This magnifies any error in the grinding.

2. I've used a center cutting end mill smaller than the desired hole size to make a short pilot hole with a flat bottom. Then I use a small hand ground HSS tool to bore the hole out to the right size. When you put the drill in the bit is guided by the edges and the point will create its own center in the flat bottom of the hole. I can do this down to about 3/16" but that's about the lower limit.

Of course, sometimes nothing seems to help...

[scb]

If I was having your problem I would start with oversized stock. Drill the hole. As long as it's straight I'd then put it between centers and turn it to the required dia.

[GabbyM]

If you use a center drill instead of a start drill you want the correct size center drill. Should be smaller than the flat on end point of drill bit. Generally never go deep enough that you start on the angled step of the C-Drill until you get into larger drill bits. If you get any chatter when your drill starts your center hole is incorrect.

Hand grinding a drill bit then reaching for deep hole accuracy is a lot to ask.
Are you planning to use a reamer to fish the bore?

[scrapcan]

good stuff added by all, thank you.

I am currently using oversize stock and drilling the thru hole first. I was not sure how to turn such a short blank od between centers? Not much to get a dog on. But maybe enough if I turn the shank that will later be threaded and turn it around and put it in a collet to turn the od of the rest of the body.

I am hoping to spend some time this evening making swarf. We shall see what interesting things I can learn!

Thanks again for all the help.

[ricksplace]

If I was having your problem I would start with oversized stock. Drill the hole. As long as it's straight I'd then put it between centers and turn it to the required dia.

Bingo!! This is what I do. Works for me.

[John Taylor]

Quote:
Originally Posted by scb View Post
If I was having your problem I would start with oversized stock. Drill the hole. As long as it's straight I'd then put it between centers and turn it to the required dia.
Bingo!! This is what I do. Works for me.

I do the same thing. Another trick is to bore in a little ways with drill and then use a small boring bar to make sure the hole is concentric, taking it out to a snug fit on the drill size a little smaller than the finished size. This makes sure the drill is centered in the work. Use a reamer for finish.