Drilling a hole in my piston....

[FerrisDiesel]

Hey all,
I'm trying to make my pusher on my Logsplitter a little beefier. So I am revamping it and also putting a bigger bolt in the pusher where it attaches to the piston.....The problem I am running into is I keep destroying my drill bits when I try and make the hole bigger. I had drilled it out, and stepped up in size to my brand new 1/2 inch bit, and got about 1/4 of the way through and it won't drill anymore. I was oiling the hell out of it too. What is the best drill bit in your opinoin for drilling through the rod of a piston???

 

[beerman6]

What size was the first hole?

Sounds like you should use the same type has the first one...

 

[HARRY BARKER]

sharpen the bit

 

[FerrisDiesel]

Yeah I am gonna have to sharpen the bit, I just cannot believe that I got 1/4 way through and it's toast, it was a brand new bit!!........the bit I used before that was brand new, and it went through like butta!!!
I would use the same hole, but what I noticed was the bolt I had in there, keeps bending and breaking........So I don't think the piston is pushing directly against the plate......or, the plates on the side of the beam are too sloppy and are making the bolt break

 

[Bushranger1]

Some types of steel "work harden" very easily. The trick is to use a slow speed with plenty of oil & keep the drill bit biting in to the cut. Whan happens is that on some material as soon as the bit begins to rub on the material being cut it will harden the surface. I have had this happen to me a few times at work & I have used a dremel grinder to just remove the hard surface so I can get started again with the drill bit.
So once you get started again as soon as you feel drill bit begin to get blunt STOP & sharpen it immediately or the friction will again harden the material surface.

 

[ray benson]

A cobalt bit would be one of the toughest for problem materials. But if it is work hardened it may dull. I would try and add a shim so the rod pushes directly on the pusher plate relieving most of the stress on the bolt. And use a grade 5 or grade 8 bolt.

 

[wvlogger]

stainless steel is hell on bits

 

[Stihl310]

I'm not sure what the hardness is on the inner core of the cylinder rod, however typically the Rc hardness specification on the outer surface is between 60-70 Rockwell... And that my friend is some very very hard material...

You'd probably be better off trying to make some kind of collar that was set screwed onto the piston shaft... you're going to beat your brains out trying to drill that hard of material

 

[skidsteer.ca]

Usually the center of the shaft is soft, after you get into it 1/16" or so you have it made. I believe it is a ceramic cutter used on a lathe to remove the outer layer so the inner can be threaded to hold the piston. You might want to try a carbide cutter on a die grinder to enlarge the hole.
Ken

 

[FerrisDiesel]

slow speed

Slow speed, I think thats where I goofed. Thanks for the advice

 

[johnny2]

as a machinist I run into material that work hardens all the time and we also do allot of cylinder work, the core is soft for flexing the outer coating is usualy chrome and induction hardened 20 to 30 percent of rod dia. I would use a cemented carbide tip drill from a place like msc these are not for cement, the carbide is silver soldered on to a high quality drill

 

[Paul61]

as a machinist I run into material that work hardens all the time and we also do allot of cylinder work, the core is soft for flexing the outer coating is usualy chrome and induction hardened 20 to 30 percent of rod dia. I would use a cemented carbide tip drill from a place like msc these are not for cement, the carbide is silver soldered on to a high quality drill

Diemaker's advise..............don't go the carbide route as you'll proly break the drill and lodge a piece in the hole. The result being.....you're SOL!
Try a newly sharpened bit @ slow speed with some lube, if it dulls right away then you'll need to grind out the work harderned area with a carbide burr 1st, before continuing.
Unfortunately you'll run into the same hardened case on the opp. side of the shaft, on exit.
Or...............you could ship it to my shop & we'll fix it $$$$$$$$$$$$$$$:hmm3grin2orange:

Paul

 

[Steve NW WI]

I agree with much of what's been said above. Low speed, and lots of lube, and it oughta cut right through with a good bit - READ NOT NORTHERN TOOL STUFF. Head down to the local hardware store, pick up a good quality, American made drill bit if you don't already have one. A cheapo drill bit will aggravate you to no end.

I also agree with the shimming idea so the cylinder rod does the actual pushing. A 1/2" bolt doesn't have nearly the shear strength that most hydraulic splitters can put out. Mine is a big one, but just for example, the push block on it is attached with a 1 1/4" pin. I'd think that a 3/4" drawbar pin would be a minimum, but depending on the size of your shaft, it might not leave a lot around it...Got Pics?

 

[FerrisDiesel]

I will post some pics tonight when I get out of work. I am going to try and put a 3/4 inch bolt in there if I can.......but like you said I might run out of room..........what should I use to grind that out with a dremel tool maybe???

 

[wvlogger]

using a dremel would take a while even with a carbide burr stainless stails is a very hard metal i thing a good titanium coated bit with lots of oil is the way to go

 

[Paul61]

..........what should I use to grind that out with a dremel tool maybe???

Yup, but only if the drill wont cut.
Also, dont use just any oil for lube, it would be best if you could get a sampler of cutting oil like"CoolTool" or "Rapid Cut" from a retail tool shop, reg. oil will only smoke.
If the cyl. shaft is Thompson rod, & not just hard chromed cyl. rod.... you're in trouble.
Wost case we can EDM it for ya?

 

[mikes mold]

rodman drills

As a toolmaker of 40yrs. All the advice above is right on. work hardening is tough. grinding the hard spot is the best, than slow speed always. I had mold plate with two 1/4 inch pipe taps, come in. I got out my set of rodman drills and drilled right down the center of the tap. Than was able to bust it out. I used the same drill on both taps. The owner of the mold plate thought I was crazy, tell he watched me. It is very much like a cement drill. PS watch out though as they will drill big. I got mine at the MN state fair.Here is there internet site.Good luck
http://www.rodmanandcoinc.com/rodmanandcoinc.com/index.html

 

[Paul61]

As a toolmaker of 40yrs. All the advice above is right on. work hardening is tough. grinding the hard spot is the best, than slow speed always. I had mold plate with two 1/4 inch pipe taps, come in. I got out my set of rodman drills and drilled right down the center of the tap. Than was able to bust it out. I used the same drill on both taps. The owner of the mold plate thought I was crazy, tell he watched me. It is very much like a cement drill. PS watch out though as they will drill big. I got mine at the MN state fair.Here is there internet site.Good luck
http://www.rodmanandcoinc.com/rodmanandcoinc.com/index.html

Mike,You OLD tooly(!)....... I hadn't heard of these drills so I checked out the site. As per. your description of the drills, the site doesn't do them justice?
I used to drill out taps with re ground masonary bits, flooded with coolant so the silver solder didn't melt!
BTW, I started my apprenticeship in 78 for 2.15/hr!

Paul

 

[mikes mold]

rodman drills

Started July 1964 $1.40 got raise $1.65 68-72 journyman tool maker was $3.60- $4.10. I used cool tool with crisco mixed, 300 RPM. Like you say coolant works well also. People don't know that the drill is expanding from the heat causing the breaking. When we make proto type out of P-20. The water lines are very tough. My son does the water lines and slows the speed way down. Drives me nuts, I just walk away. I can't remember when he has broke a drill. Becareful if you get rodman they drill big and are hard to stay on location. I use them to get out of trouble only. PS they are guaranteed for life.I keep mailing the broke ones back and they send me new ones. Mike