Racor bowl fasteners 500FG obsolete model

[paulga]

The obsolete model has Phillips head screws as the bowl fasteners. Racor told me these Phillips head are no longer available. I purchased the current fasteners that have hex head screws, but it only goes in by a couple of threads by hand. I didn't use a screwdriver to force it in

This is my racor model. The old fasteners are RK15081-01



Both screws have 10-24 threads so should they be used interchangeably?

 

[CharlieO.]

You could always run a tap into it to chase the threads. Tap and die set is a very useful addition to the toolbox.

 

[tiltrider1]

They both say 10-24. You can go to the hardware store and buy some 10-24x7/8 screws and confirm your issue. What happened to the original screws?

A thread chaser would be more appropriate tool but careful use of a tap would work.

 

[TJM]

Kind of confused here. What was wrong with the original screws? Just match them.
10-24 is a standard machine screw thread. Ø .190 major diameter with threads of 24 threads per inch. Maybe the old screws were shorter and the holes got clogged? As mentioned be careful re-tapping into plastic, it can cross thread very easy or crack.

 

[paulga]

Kind of confused here. What was wrong with the original screws? Just match them.
10-24 is a standard machine screw thread. Ø .190 major diameter with threads of 24 threads per inch. Maybe the old screws were shorter and the holes got clogged? As mentioned be careful re-tapping into plastic, it can cross thread very easy or crack.

two of the original screws are sort of stripped in the head over the years, i was not able to drive them after some point so I don't know if I was able to reach the required 60 in lbs yesterday.

the original screws (RK15081-01) are #10-24 x1 in, they screw all the way in by hand.
new screws (RK15081) are #10-24x 7/8 in, it goes in only two threads by hand

both are 10-24, i don't know what the difference is

 

[paulga]

They both say 10-24. You can go to the hardware store and buy some 10-24x7/8 screws and confirm your issue. What happened to the original screws?

A thread chaser would be more appropriate tool but careful use of a tap would work.

i already bought 3 sets of RK15081, this is the currently available fasteners, 10-24x7/8" hex heads

the screws on my racor are the old ones RK15081-01, 10-24x1" phillips head (discontinued, two screw heads are stripped a bit)

I have not used a chaser nor a tap before. I think you mean to remake the threads inside the screw hole, but the threads are not damaged, it is the screw head that is a bit stripped. Anyway to remake the screw heads?

or can i buy some 10-24x1in machine screws, like this combination drive or phillips heads?

 

[CharlieO.]

Take your old screws to the hardware store to match up. Perhaps one set is not really 10-24. If you hold the old and new screws together do the threads mesh up completely?

 

[tiltrider1]

Compare the threads between the old and new screws to confirm that they are the same. If different then you know the replacements are mis marked.

You can take the old screws to a hardware store and match them up to some new replacements.

Stainless and aluminum combined will suffer from dissimilar metal corrosion over time. If this is your issue then a thread chaser or tap will be needed to clean out the corrosion.

 

[Comodave]

two of the original screws are sort of stripped in the head over the years, i was not able to drive them after some point so I don't know if I was able to reach the required 60 in lbs yesterday.

the original screws (RK15081-01) are #10-24 x1 in, they screw all the way in by hand.
new screws (RK15081) are #10-24x 7/8 in, it goes in only two threads by hand

both are 10-24, i don't know what the difference is

Per this post the new screws are 1/8” shorter than the old ones. Get some new ones that are the same size. Chase the threads with a tap to clean them out. Then use a lubricant like TefGel when you put the new screws in. Put them in and back them out repeatedly and see if they gradually go in further.

 

[paulga]

Per this post the new screws are 1/8” shorter than the old ones. Get some new ones that are the same size. Chase the threads with a tap to clean them out. Then use a lubricant like TefGel when you put the new screws in. Put them in and back them out repeatedly and see if they gradually go in further.

i'm thinking if I could modify the screw heads:

drill a hole in a scrap wood, put the screw all the way in, use a dremel tool with cutting piece ez456 (blade thick 0.045in) to cut a slot on the middle of the head, so I could drive it using a flathead

 

[Comodave]

That may work but I really don’t like to do make shift repairs on my boat unless absolutely necessary. The screws are likely available to buy a couple of new ones and at a small cost.

 

[SteveK]

i'm thinking if I could modify the screw heads:

drill a hole in a scrap wood, put the screw all the way in, use a dremel tool with cutting piece ez456 (blade thick 0.045in) to cut a slot on the middle of the head, so I could drive it using a flathead

Why don't you go ahead and do that, then let us know, but post a picture or two.

 

[paulga]

Why don't you go ahead and do that, then let us know, but post a picture or two.

Don't know if this is commonly done and if ez456 is the right tool, if the cut groove does not grip or tend to strip. With no spares, I cant afford to mess it up

 

[luna]

If indeed you have purchased 3 sets of RK15081, 12 hex washer head cap screws, why don't you use them?

If they don't thread in to the body, try this. Take a small piece of cloth, saturate it with vinegar and stuff it in the threaded fastener hole for about 15 minutes.
Remove the cloth and twist a brass (or stainless) 3/16" diameter bottle (or pipe cleaning) brush in the hole following the threads. Amazon has them, but buy a kit of various sizes if possible as you will need them later for other threaded holes. Size here is important as you want the ends of the bristles to clean out the threads. Don't use a 1/4" brush as you with crush it.

Rinse well using a trigger bottle with water (plus baking soda if you are anal) then twist in a pipe cleaner with a rag cover to dry the threads.

Now try you new Racor RK15081's by hand, they should go easily. If not, repeat the process.

You stated that you intend to torque these machine screws to 60 inch pounds. Are you sure about that? A #10-24 stainless? machine screw can only be torqued to about 22 inch pounds Max, much more and you will likely twist the head off or pull the threads out of the aluminium body. Wouldn't that be a joy!

If the requirement is for 60 "/lbs. the machine screws and a threaded insert cast into the body would both need to comply with ASTM 574 which is a carbon steel, quenched and tempered fastener/insert, that in that size is exceedingly rare. I doubt Racor would use such a thing as by simply upsizing to a 1/4"-20 bolt, like on their larger units, would allow that amount of torque. All you are doing is compressing a square section O ring to affect a seal in a non-pressurized vessel, why so tight using such a small fastener?

If you try to cut a drive slot in the original damaged machine screws you could easily twist off half of the head leaving you hooped. The original Phillips drive was likely damaged by someone using the wrong tool, while trying to drive the fastener up hand. Don't repeat other peoples mistake.

Clean the threaded bores and use the new hex washer head fasteners.

 

[paulga]

Take your old screws to the hardware store to match up. Perhaps one set is not really 10-24. If you hold the old and new screws together do the threads mesh up completely?

Yes, it turns out the "original" screw is not 10-24x1 as specified in the manual. Here is a side to side comp of the original vs RK15081 10-24x7/8 hex vs 10-24x1 machine screw from HD

Their threads match up in each pair. The original screw is very similar to 10-24x7/8. I have no idea why the new screw does not want to go in

 

[paulga]

If indeed you have purchased 3 sets of RK15081, 12 hex washer head cap screws, why don't you use them?

If they don't thread in to the body, try this. Take a small piece of cloth, saturate it with vinegar and stuff it in the threaded fastener hole for about 15 minutes.
Remove the cloth and twist a brass (or stainless) 3/16" diameter bottle (or pipe cleaning) brush in the hole following the threads. Amazon has them, but buy a kit of various sizes if possible as you will need them later for other threaded holes. Size here is important as you want the ends of the bristles to clean out the threads. Don't use a 1/4" brush as you with crush it.

Rinse well using a trigger bottle with water (plus baking soda if you are anal) then twist in a pipe cleaner with a rag cover to dry the threads.

Now try you new Racor RK15081's by hand, they should go easily. If not, repeat the process.

You stated that you intend to torque these machine screws to 60 inch pounds. Are you sure about that? A #10-24 stainless? machine screw can only be torqued to about 22 inch pounds Max, much more and you will likely twist the head off or pull the threads out of the aluminium body. Wouldn't that be a joy!

If the requirement is for 60 "/lbs. the machine screws and a threaded insert cast into the body would both need to comply with ASTM 574 which is a carbon steel, quenched and tempered fastener/insert, that in that size is exceedingly rare. I doubt Racor would use such a thing as by simply upsizing to a 1/4"-20 bolt, like on their larger units, would allow that amount of torque. All you are doing is compressing a square section O ring to affect a seal in a non-pressurized vessel, why so tight using such a small fastener?

If you try to cut a drive slot in the original damaged machine screws you could easily twist off half of the head leaving you hooped. The original Phillips drive was likely damaged by someone using the wrong tool, while trying to drive the fastener up hand. Don't repeat other peoples mistake.

Clean the threaded bores and use the new hex washer head fasteners.

Thanks for the details. will try cleaning the thread hole if necessary

60 in. lbs is specified in the cut sheet. with phillips head screw, I would just hand tight using a screwdriver, as driver bits on a torque wrench will not be accurate

 

[BruceK]

I`m a tad confused. Do you have the extracted screws? Will they go back in? Are they beyond further use? If they fit and new identical ones don`t, I don`t get it. I`d want to reuse, but maybe the old ones are really "screwed".

Going in 2 threads and no more in my limited experience suggests incompatible threads. Maybe it just needs cleaning as luna advises. How does a hole get that corrupted?

I think SteveK was being "mischievous", don`t do that.

 

[paulga]

I`m a tad confused. Do you have the extracted screws? Will they go back in? Are they beyond further use? If they fit and new identical ones don`t, I don`t get it. I`d want to reuse, but maybe the old ones are really "screwed".

Going in 2 threads and no more in my limited experience suggests incompatible threads. Maybe it just needs cleaning as luna advises. How does a hole get that corrupted?

I think SteveK was being "mischievous", don`t do that.

i have removed only one screw. yes it goes back in. I have to reuse the original screws. it's the rational option without knowledge of the screw's specs. Two of the original screw heads phillips drive are already sort of stripped, so after some point i cannot turn it further. i don't know if this point is tight sufficient. that's why i'm looking for new screws

 

[luna]

If you are convinced that the new Hex Washer Head Capscrews are the same size and thread as the original Fillister headed screws that fit, then, provided the hex washer head does not foul the bowl, it can only be the threaded bore that is the problem.

Perhaps the one location that you tried is being difficult. Remove another of the original screws and try the new Hex Head screws in that location.

Here is a fastener torque chart that may be useful.
https://www.fastenal.com/content/me...nt-library/Torque-Tension Reference Guide.pdf

 

[SteveK]

If you are convinced that the new Hex Washer Head Capscrews are the same size and thread as the original Fillister headed screws that fit, then, provided the hex washer head does not foul the bowl, it can only be the threaded bore that is the problem.

Perhaps the one location that you tried is being difficult. Remove another of the original screws and try the new Hex Head screws in that location.

Here is a fastener torque chart that may be useful.
https://www.fastenal.com/content/me...nt-library/Torque-Tension Reference Guide.pdf

Luna. Magnify the pic of screws. the middle one, hex head is different thread. The other two look close and may be the same.

 

[SteveK]

Don't know if this is commonly done and if ez456 is the right tool, if the cut groove does not grip or tend to strip. With no spares, I cant afford to mess it up

I thought you could not replace it as the head is stripped so the slot idea is to salvage an otherwise good screw. I don't understand wht then you have to lose. No good as is and may still be no good after.

 

[Nick F]

60 in-lb is definitely wrong ! Don't even think of applying this torque!

6 in-lb may possibly be enough.

 

[TJM]

This thread is becoming painful to follow. NO WAY would I cut a screw driver slot in the head of a hex head. A straight bladed screw driver slot is the worst / weakest way of transferring rotational energy to a screw. Too much slippage. Buy the correct screw for a few bucks, readily available at any hardware store or McMaster carr.

 

[luna]

Luna. Magnify the pic of screws. the middle one, hex head is different thread. The other two look close and may be the same.

From the pictures I would not want to guess as to whether the threads are the same. Paulga has stated that they all match, effectively so has Racor.

From this side of the Continent the problem exists in the threaded bore.

It could be as simple as this. At some point in the past, as evidenced by the damaged drive, someone had these fasteners out.

When this someone reinstalled the fasteners they cross threaded the bore. This gets evident in about 2 turns as the force required to form the new threads gets extreme and the fastener is quite crooked.
At this point they remove the fastener and then started it straight, in the original threads and drove it home. All is good as only about 2 threads are damaged. The damage however, still exists.

When Paulga tried the new Hex Head fasteners he could have found this 2 turn dead ended cross threaded path.
Hopefully by trying another threaded bore no cross thread exists and the fastener turns in by hand.

 

[paulga]

I never doubted the cut sheet

But the sort-of head-stripped screws definitely still allowed me to tighten it to 6 in lbs

60 in-lb is definitely wrong ! Don't even think of applying this torque!

6 in-lb may possibly be enough.

 

[paulga]

This thread is becoming painful to follow. NO WAY would I cut a screw driver slot in the head of a hex head. A straight bladed screw driver slot is the worst / weakest way of transferring rotational energy to a screw. Too much slippage. Buy the correct screw for a few bucks, readily available at any hardware store or McMaster carr.

I was saying to cut into the head of the Phillips screws that are sort of stripped. I thought they are rk15081-01 according to the cut sheet, but now I see they are not. They were probably installed by a previous owner. I guess they are 10-24x7/8

The hex screws, rk15081, are the new screws I bought from racorstore. They are 10-24x7/8.

 

[paulga]

I sent the picture of the screws to racor but still waiting them to get back.

will try another screw later

From the pictures I would not want to guess as to whether the threads are the same. Paulga has stated that they all match, effectively so has Racor.

From this side of the Continent the problem exists in the threaded bore.

It could be as simple as this. At some point in the past, as evidenced by the damaged drive, someone had these fasteners out.

When this someone reinstalled the fasteners they cross threaded the bore. This gets evident in about 2 turns as the force required to form the new threads gets extreme and the fastener is quite crooked.
At this point they remove the fastener and then started it straight, in the original threads and drove it home. All is good as only about 2 threads are damaged. The damage however, still exists.

When Paulga tried the new Hex Head fasteners he could have found this 2 turn dead ended cross threaded path.
Hopefully by trying another threaded bore no cross thread exists and the fastener turns in by hand.

 

[koliver]

Paul:
I am not at my boat, so the following is from memory and may not end up being the same Racor as yours, but....
As I recall, my Racors are assembled with the same screws in every position. None are 10/24. None are a machine screw thread, and due to the material being plastic, I would never expect them to be threaded into a 10/24 tapped hole in the plastic That thread is for using a nut on the other end. The racors (mine at least) tighten a much taller thread into the plastic body, maybe as tall as 6 tpi. The diameter may well be the same as a 10/24 machine screw, so if you can fit a nut on the other side, that may well be what Racor is telling you to do. Mine is much more akin to a wood screw than to a machine screw.
Again, as my Racor 500s are older than dirt, they may not be the same as yours.

 

[paulga]

Paul:
I am not at my boat, so the following is from memory and may not end up being the same Racor as yours, but....
As I recall, my Racors are assembled with the same screws in every position. None are 10/24. None are a machine screw thread, and due to the material being plastic, I would never expect them to be threaded into a 10/24 tapped hole in the plastic That thread is for using a nut on the other end. The racors (mine at least) tighten a much taller thread into the plastic body, maybe as tall as 6 tpi. The diameter may well be the same as a 10/24 machine screw, so if you can fit a nut on the other side, that may well be what Racor is telling you to do. Mine is much more akin to a wood screw than to a machine screw.
Again, as my Racor 500s are older than dirt, they may not be the same as yours.

the 24 in 10-24 is not tpi?

the fasteners and the top section are made of plastic? I thought those are metal

 

[koliver]

the 24 in 10-24 is not tpi?

the fasteners and the top section are made of plastic? I thought those are metal

yes, tpi.

as I said, mine is older than dirt. Yours may be different. Easy enough to check.