Pipe threads in cast Iron

I don�t have this tap, so as I was looking through the McMaster-Carr catalog, I see they have a Pipe Reamer for NPT in 1� (pg 2167). Can I just ream the existing hole to 1�, or do I drill, ream then tap? Or they also have NPS taps in 1�(pg 2084) that can be used in low PSI conditions, which this is, as it�s the suction line going to a pump. What size drills do I need for these application, I can�t find a reference guide for pipe threads this size?

How would you do this, and what would be the easiest way and safest (don�t want to make a mistake and hurt Casting). Remember this is the rear end drain plug that I am talking about so laying on the ground under the Tractor is part of the job. I have drilled and taped many holes in steel and have cleaned NPT fittings in cast but never drilled and taped a new hole in cast, what do I need to know?

TIA
Dave

Taper pipe drill sizes: 1/4" pipe, use 7/16 drill.
3/8" pipe, use 9/16 drill.
1/2" pipe, use 45/64 drill.
3/4" pipe, use 29/32 drill.
1" pipe, use 1+9/64 drill.

Chart does not state whether these holes are to be tapered first, or tapped as is.
In a one chance situation, it's always best to practice on some like kind scrap material first.

JMHO

Jet

Sk # McMaster st ell 50925K277 adapter 50925K325 (Four year old catalog)

Some ten years ago at a sale there was a JD industrial back hoe off of a 400 JD TLB nothing else. Well when the bidding was done, I owned it knowing I would try and mount it as it had been, but on my 806(can you see my stupidity).

That winter I remounted the Freeman loader on the 806 to accommodate the BH mountings just like OEM (the light still isn�t on). A very time consuming job, but I do like a challenge.

All was well till I hooked up the Hydraulics and tried my new investment (the light came on). What a Bone head I was and my cheap BH was a big mistake!

I�ve tried over the years to find a valve stack that would bolt on for open center hydraulics or covert this one with no luck, but I did find a company that would help with finding the pump I needed.

So to get this mistake working, I bought A Vicers PVB-29 a variable volume, pressure compensated, piston pump to run off the PTO, made a gear case that will run the pump at the recommended RPM, and bolt to the back of the tractor just below the 1000 RPM PTO. Now if I can get the oil to the pump. With this style pump oil flows on demand only when a function is used, unlike an open center hyd system, so will oil heating be any different than the OEM JD 400 tractor? I have tried to find specs on the internet for a 400 JD, but haven�t found any yet, anybody have a OM that can help?

Many Thanks to everyone that has helped, and made me think!
Dave

• cooler/fan combination

I think you"ll be very disapointed with using the hydraulic oil in the differential if your going to working the backhoe any length of time, over 15min as the oil will heat very quicky.

You might get away with using a large oil cooler for a longer run time but you would have to have the plumbing to where you can circulate the oil after using the backhoe hydraulics or allow sufficent cool down after using the backhoe or the tractor hydraulics will suffer.

28gpm is alot of oil. Most smaller backhoes use less than 20gpm pump. I would add a external tank under the seat or?

I ran into problems with my 340U with a Pippin loader/hoe with a 17gpm pump as I can get about 1/2hr run time using the differential oil. Thats it, then it needs to sit for 3 or 4hrs before using again as with the thinn oil there"s just not enough hydraulic pressure to continue working.

On My 806 there is a unused steel plate on the low right side of the tramission that could be drilled and tapped. I think it was suppose to be for the belt pulley/4wd intall.

T_Bone

The belt pulley bolts direct to the housing over the 1000 RPM PTO.

But could the plate you are talking about be on the left hand side under the clutch peddle? That�s where the MFWD gear case bolts. Just walked out to look for sure and that�s the spot I need!! A replaceable plate that I can remove to drill and tap, it�s low enough to draw oil but better yet not on the bottom of the case. I think you�ve done it!!!

Thank You!!!
Dave

This is the reason for this exersize, is to use the 17 gallon of oil already in the trans and the oil cooler the tractor has.

The Loader frame of this 1960's Freeman Loader was abandon for oil storage a long time ago when it was on the WD-45.

Dave

I'm amazed a tractor backhoe needs that big a pump, this must be some monster big hoe!!!!!

--->Paul

Just screw in a 3/4" street elbow (with Rectorseal #5 on the threads) stop with it to the rear. Screw in a 3/4" close nipple, then a 1 to 3/4 reducing coupling. Then you have your 1" female threads to take your return line. A really well supplied hardware store might even have a street elbow with 3/4" male threads and 1" female threads. Or a reducing elbow and a 3/4 close nipple gets there quickly.

And you've not filled the system with ground up cast iron that will otherwise grind the pump and valve to make more ground steel and iron to further self destruct.

Gerald J.

My problem is that it will be the Suction side of a 28 GPM pump, and I don't know if I draw that volume threw a 3/4" NPT nipple.

Dave

Do you really NEED 28 GPM for your back hoe? the WD45 didn't have that kind of flow but had higher pressure so they cylinders might be a bit small in diameter.

I have a Long 1099 and I find its a whole lot more controllable with a 5 gpm pump than a 10 or 22 gpm pump.

I run it on the JD 4020 hydraulics through a flow restrict or valve to keep from jerking it apart.

Gerald J.

However, I have two concerns:

Unless I knew exactly what was on the other side of that hole, I wouldn't do it. Remeber, taps are tapered and to get a good thread you have to penetrate the hole, at that size anyway, by an inch or two. Of course, you could get a pilot tap to start the hole and a bottom tap to finish the hole.

I'm curious why you want to enlarge this drain. You mentioned it will be a suction line. If that means you will have a hose connected to this drain, I'd be worried about knocking it off. Is there another way to approach this? Some other line or hole available on the side of the case?

To answer your conserns, The first one is well taken. Maybe I better drain the oil and look and feel before I start putting good money(order tooling) on a unusable hole.

These fitings will safely hide behind the 2pt fasthitch arms, so i'm not worried about breakage.

Dave

--->Paul

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