Fast hitch - Front Depth Crontrol Screw thread size

[J3 Driver]

So I was able to get a new housing for my fast hitch. Screw that i had won’t fit. It’s the wrong thread direction. Thought it was acme thread 3/4-6 so I ordered some stock to have welded to the handle. Only problem is it gets very tight in the depth control housing that you can’t turn it.

Does anyone know what the correct thread size is?

Thanks

Keith.

 

[Jim Becker]

You probably have the correct size. But:
viewtopic.php?f=1&t=102311&p=809119#p809119

 

[tst]

I believe Jim is correct, in 3/4 " I am pretty sure they only had one thread pitch

 

[tst]

found my acme chart, 3/4 comes in three different pitches, 5, 6, and 8, so figure out which pitch you have and a new rod is less than $10 with a single thread start, perhaps you just bought the wrong pitch?, just mark off an inch on the old rod and count how many times you turn it to complete the one inch and that is your thread pitch
look at the end of your old rod, if it is a "double thread" you will see two spots where a not would start as opposed to a regular bolt that is commonly used where only one thread at the end to start the nut, not sure if they sell a double threaded rod if you need one, they were not common, let us know what it is you find out in the end, make it easier for the next guy to deal with
Tim

 

[J3 Driver]

The problem is I don’t have an original one to look at. The one that I did have was made by the previous owner. It’s is left hand thread instead is right hand hand and has an insert that Goes into a pipe welded on top of the housing. It will work but isn’t correct.

 

[Rick Spivey]

If you have a Fastenal or other screw vendor nearby, take your housing to them and I'd bet they could measure the thread pitch. On an Acme thread of that size, if the pitch was off, I don't think it would take many turns to realize it (6 into a 5 is possible, the 8 is probably not in consideration here). How far into the housing did your threaded rod go before seizing? If more than an inch or two, then I'd bet there is something in the housing, such as dried grease?

 

[J3 Driver]

Couldn’t get it more than a turn. Housing is brand new old stock. I’ll run it to grainger or fastenal and see what I can come up with.

 

[Slim140]

Measured one I have. It’s 7/8-6 triple lead.

 

[J3 Driver]

Part number 4 in this is that big?

The 3/4 seemed the right width to me. Just wouldn’t start.

 

[Slim140]

Yes sir, this one right here. 7/8-6 triple lead.

 

[J3 Driver]

My friend. Would you like to sell it. Those disk rods are really nice you made for my son’s disk. Would it be possible to make piece number 4 in my post above. I’ll gladly pay you.

 

[Slim140]

I don’t want to sell it, it goes with a fast hitch I have. I been looking for a acme rod and haven’t had any luck yet. Cutting acme thread gets difficult when it’s that long. It’s hard to keep the shaft from flexing on a lathe.

 

[Bob McCarty]

McMaster Carr sells 7/8-6, but I don't know if it's double lead or not. You could always buy the rod with a matching nut to replace the one on your end if it's single lead.

 

[J3 Driver]

I found some from MSC. 46.00 for a piece 3 feet long. That’s a lot cheaper then any thing else I’ve found. Might give it a try.

 

[Glen]

Hi,
You should measure them carefully.
It's possible IH used both sizes of rods you guys have talked about.

 

[tst]

I cut a single acme a while back that was 3/4, that was a project I do not want to do again, once was enough and it was no fun, a double thread would push me over the edge, probably could not do that anyway, that is what CNC is for

 

[Slim140]

I cut a single acme a while back that was 3/4, that was a project I do not want to do again, once was enough and it was no fun, a double thread would push me over the edge, probably could not do that anyway, that is what CNC is for

The man that runs our lathe, I’ve seen him cut quadruple lead before. Not me, lol.

 

[tst]

I had enough grief with one let alone 4

 

[Slim140]

I found some from MSC. 46.00 for a piece 3 feet long. That’s a lot cheaper then any thing else I’ve found. Might give it a try.

I looked at MSC's website, if it's the one on there I saw for $46 it's not double lead and it will not work.

I did a search and here's a chart to help understand acme thread and single, double, triple & quadruple lead threads.http://www.cadcamengineering.net/wp-con ... 01/409.jpg

A double lead thread turns twice as fast as single lead, triple three times faster, etc. They will not interact with each other as both the male and female parts have to match.

 

[Slim140]

Keith ask me to measure this rod for him. Glad I took it apart. It’s actually 7/8-6 TRIPLE lead.