Help with faceplate threads

Technical Ted said:
That's a good ol' 60 degree V thread which is the most common in the USA. I'm more concerned with the thread in the face plate being that same type and at the proper pitch diameter.

Also, another thing to keep in mind, is that face plates can be purchased "blank" meaning no threads to mount on a spindle so the new owner can thread their own as desired. It is certainly possible that the previous owner threaded this himself and didn't take the thread to full depth for some reason... maybe he fitted it to an under size spindle??? Who knows.

If it is the case where the threads just aren't deep enough, it could be put on a lathe, indicated in, and very carefully line up a internal single point threading tool on the original thread and then taken to depth. That is what I would do if I found myself in this situation. It sounds more difficult than it is if you've never done it before. You'd have a nice large bore and coarse thread to give you a big advantage over a much smaller bore. You run the threading tool in using your half nuts, stop the spindle while the tool is inside and then line the tool up in the thread using your compound and cross feed. Do this over and over a few times making very small adjustments until you just start to make a chip and then go from there. Doing this type of work is a great skill to have in your tool belt. Just go very slow and carefully. One additional word of advice is to make sure your threading tool has sufficient clearance because you will be inside a bore and you don't want it rubbing.

Ted
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I just learned that skill yesterday (chasing a thread) as I had something go wrong and I do not fully understand what happened. I don't think I backed out the cross slide enough after taking a bunch of compound cuts and when I moved the carriage to the right the tool bit hit each thread (like click click click click etc) but I just said oops (really said #&*!$@) and just went in for the next cut on the compound. It started to cut and then caught on something and moved the part in the chuck and made it wobble a little. I then said "#&*!$@" again and remembered something I read somewhere about if that happens..."don't worry as it's easy to fix". So I re -chucked the part and got it spinning true and engaged the half nut with the tool away from the part and then stopped the machine with the half nut engaged. I move the cross slide and compound until it looked right and finished the part. I was proud. I do plan on making one more of these adapters as the 3rd time is the charm, right?

I will see if that method above is something I want to tackle but first I am going to buy a few more tools like a Starrett thread gauge that has 8 TPI on it. My cheap set does not go that low. I have thread rods for measuring but didn't use them as I am going to need to practice with those first. I think grease would help or I need an extra hand.

But you are correct. The "who knows" factor is there and is just my luck. The good part is that I somewhat successfully cut the 2 1/4 - 8 TPI threads and they actually feel pretty good as far as fit. The finish, not so much. But when I make the 3rd one I will have experience. :) And based on that "flat" spot on the entire thread on the faceplate that does not fit, it may be the problem all along that the cut is not deep enough.
Thanks,
schemer
 
Here's my advice on using thread measuring wires. No matter what you use (if anything) to help hold them in position clean your chip pan out first!!! Ask me how I know... I spent I don't know how long searching for one once. I did finally find it, but never again will I use them with a bunch of chips/shavings under where I'm measuring! ;)

I'm sure you'll get the hang of it. Keep your cutting tools sharp and use a good quality threading oil on steel.

Good luck!
Ted
 
Technical Ted said:
Here's my advice on using thread measuring wires. No matter what you use (if anything) to help hold them in position clean your chip pan out first!!! Ask me how I know... I spent I don't know how long searching for one once. I did finally find it, but never again will I use them with a bunch of chips/shavings under where I'm measuring! ;)

I'm sure you'll get the hang of it. Keep your cutting tools sharp and use a good quality threading oil on steel.

Good luck!
Ted
Click to expand...

Thanks for all the help. I will let you know what happens when I get it done. I ordered a used Starrett thread gauge on ebay for future reference that goes to the lower TPI range although it will probably be rare to use/need it after this. I need to get a thread mic too. On the cutting/threading oil I have been using that sulphur smoking stuff from Lowes and Home Depot:
http://www.homedepot.com/p/Oatey-16-oz-Dark-Thread-Cutting-Oil-302032/203461243
But I have others. I even bought some of that Boeshield paste: http://orelube.com/products/paste/ but I haven't tried it yet. I have others too but used what was handy. What is a good tried and true thread cutting oil. I have lard and can mix it with mineral oil but just recently read about that but haven't tried it yet. Seems I read 60/40 with the lard and mineral oil. And the threads I have cut in the past I did fine but they were like 1/2 or 3/8 and this project was on unknown steel I bought from ebay. I know one thing for sure it isn't 12L13 or 12L14. :) I just looked it up and it is DOM tubing so most likely 1020 or 1026 steel so I guess seeing it turns fine it should thread fine too. At least I know it will be weldable.
 
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You could try wrapping the male thread with a tight wrap of teflon tape. Turn it into the other plate that it goes into, turn it back out and look at the tape. Then remove the tape and wrap it with a new piece, and try it in the one that won't go in. Turn it back out and look at the tape. If it is shredded at the points of the thread then I would think that the female thread isn't deep enough. If it goes on furtherthan before, then maybe you do need some lubricant on the threads.

Jerry
 
schemer said:
Thanks for all the help. I will let you know what happens when I get it done. I ordered a used Starrett thread gauge on ebay for future reference that goes to the lower TPI range although it will probably be rare to use/need it after this. I need to get a thread mic too. On the cutting/threading oil I have been using that sulphur smoking stuff from Lowes and Home Depot:
http://www.homedepot.com/p/Oatey-16-oz-Dark-Thread-Cutting-Oil-302032/203461243
But I have others. I even bought some of that Boeshield paste: http://orelube.com/products/paste/ but I haven't tried it yet. I have others too but used what was handy. What is a good tried and true thread cutting oil. I have lard and can mix it with mineral oil but just recently read about that but haven't tried it yet. Seems I read 60/40 with the lard and mineral oil. And the threads I have cut in the past I did fine but they were like 1/2 or 3/8 and this project was on unknown steel I bought from ebay. I know one thing for sure it isn't 12L13 or 12L14. :) I just looked it up and it is DOM tubing so most likely 1020 or 1026 steel so I guess seeing it turns fine it should thread fine too. At least I know it will be weldable.
Click to expand...

There are a lot of synthetics out there that I'm sure are very good, but I just use the good ol' sulfur smoking stuff. I bought a can of Rigid pipe threading cutting oil years ago and still use that. I use it for tapping, threading and whenever I want a nice finish cut on steel (99% of the time I use HSS cutting tools).

That lard and mineral oil thing is a little dated. Be careful because the lard can become rancid. Never tried it myself and probably never will.

Good luck and have fun,
Ted
 
jerrythepilot said:
You could try wrapping the male thread with a tight wrap of teflon tape. Turn it into the other plate that it goes into, turn it back out and look at the tape. Then remove the tape and wrap it with a new piece, and try it in the one that won't go in. Turn it back out and look at the tape. If it is shredded at the points of the thread then I would think that the female thread isn't deep enough. If it goes on furtherthan before, then maybe you do need some lubricant on the threads.

Jerry
Click to expand...

The part won't even barely start on the one it doesn't fit on so the teflon tape test won't work I'm afraid. And lube is not the issue. I am pretty sure though the thread on the faceplate is just not cut deep enough. I found a tap on ebay and made a best offer and got a deal on it. The way I see it I can use the tap, fix the problem (hopefully), and sell the tap on ebay and break even. :)
 
Technical Ted said:
There are a lot of synthetics out there that I'm sure are very good, but I just use the good ol' sulfur smoking stuff. I bought a can of Rigid pipe threading cutting oil years ago and still use that. I use it for tapping, threading and whenever I want a nice finish cut on steel (99% of the time I use HSS cutting tools).

That lard and mineral oil thing is a little dated. Be careful because the lard can become rancid. Never tried it myself and probably never will.

Good luck and have fun,
Ted
Click to expand...

Ted,
I found a tap on ebay, made an offer, and got it! So I will try that first in the hope that it isn't cut deep enough. If the tap fixes it, I can sell the tap on ebay and get my money back. If it doesn't work, I will be ready to attempt the thread chasing trick.

I figured lard would go rancid but never tried it. I use HSS 99% of the time too. I just don't do as much threading on the lathe but do tap holes a lot normally with manual tap handles. Always wanted to get a TapMagic or whatever they call those tapping heads but they aren't cheap.
 
Well, I would say that the tap will fix the problem regardless of what the real issue is! :)

Please let us know how everything turns out for you.

Ted
 
Is there anyway the relief cut in back isn't large enough to fit the lathe boss or register it's called. If it's tight there it won't allow the threads to work . Try dykem on the inside before the threads . It may be there's not enough to allow the threads to enter. It looks like it's exact size to the pitch no room to move. Try spinning it on backwards .
 
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