[m_ridzon]

I built a little widget a few years ago from 1/4" mild steel. It has a 5/8" hole in it and I now need to revise the design to enlarge the hole to 1-3/8". What suggestions do you have for enlarging the hole? I don't think I can use a traditional hole saw, since they require a 1/4" pilot hole (my hole is already at 5/8"). And I do need it to be reasonably precise so a bearing will snugly fit in the hole (it's a slip fit, not a press fit). In other words, a sloppy cut that ends a few tenths bigger may be a problem. I have a metal lathe, but can't figure out how to accomplish this in a lathe. Or maybe I can do this in my drill press, but again, I'm not sure how and am trying to avoid an expensive tapered reamer bit.

Any tips?

 

[cocomonkeynuts]

You can use 2 hole saws to accomplish this. a 5/8 and 1-3/8.


https://youtube.com/watch?v=9-pBlZa1RBI

 

[Colbyt]

I would use a step bit. 1-3/8" is the largest I've seen.



https://www.harborfreight.com/search?q=step bit

 

[Nealtw]

Clamp it down and use the hole saw on the drill press. Don't need a pilot.

 

[Rough Rooster]

Machine a shoulder bushing to fit the 5/8" hole with a 1/4" center hole. Fit bushing and drill eith golesaw.

If you have a 4 jaw chuck, you can get creative with setup and possibly use lathe and boring bar to accomplish what you want.

RR :smile::smile:

 

[SPS-1]

If you can clamp a piece of wood to it, you can use your 1-375" hole saw to bore a hole in the wood, then use the wood as a pilot for the OD of the hole saw. For best results, use a hard wood like maple, and better yet, glue 2 0r 3 pieces together for more thickness.

But if you have a lathe, I would think that the better way would be to make a flange that accurately hold the bearing, and then bolt the flange to your 1/4" plate. But it would still be best to open up the hole in the plate so that the inner ring does not rub on the plate (might not be too critical depending on what you are doing with it).

By the way, if bearing is 35mm OD, thats actually 1.378".

 

[Missouri Bound]

I would use a step bit. 1-3/8" is the largest I've seen.
https://www.harborfreight.com/search?q=step bit

That's a huge step bit.
Oddly enough they seem to work quite well in heavy metal.
Other than the double hole saw idea, the step bit should work.
Clamp it down very well....that bit is going to grab the work.

 

[Colbyt]

Always use cutting oil with the heavy stuff. It will make the bit last a lot longer.

 

[m_ridzon]

These are some great ideas folks. Thanks! But in my mind, I'm trying to cobble together a way to use my small boring bar on the drill press, so I can bore the hole to a precise diameter. I wonder if I can do that somehow. That way, the bearing will fit snug in the hole (not a press fit though).

 

[Nealtw]

 

[SPS-1]

Might want to consider investing in a small boring head. Most commonly going to see them with taper shank, but you will also see them with 7/8-20 thread and available straight shank.

One of the handiest tools I have. I use it for woodworking commonly too. Most recently vacuum hose adapter and making wood plugs to go over screw holes -- able to dial in the size perfectly.

 

[Nealtw]

Or just use the old school hack and drill the hole out to 1 5/16 and fine tune the hole with a hone made out of sandpaper set in a shaft.

 

[m_ridzon]

https://www.youtube.com/watch?v=QijnQIwtcTw

Thanks for this video. It was very informative and revealed my suspicions of the poor behavior from a traditional hole saw and step-taper bit. In fact, he illustrated the exact scenario I'm doing; i.e., a flanged bearing in a hole. I'm going to check into the cutter they showed.

Might want to consider investing in a small boring head. Most commonly going to see them with taper shank, but you will also see them with 7/8-20 thread and available straight shank.

This is another great idea. Do you have any links for where I can buy one?

 

[SeniorSitizen]

Just shooting in the dark here but is there a possibility a flange bearing could be used. If so there is another possibility it could modify a similar bearing assembly for nearly 0.0 cost.



https://3bgsupply.com/bearings/moun...MInqOE6ffJ5wIVQv_jBx0SRAXNEAQYASABEgKrgfD_BwE

 

[m_ridzon]

Just shooting in the dark here but is there a possibility a flange bearing could be used. If so there is another possibility it could modify a similar bearing assembly for nearly 0.0 cost.



https://3bgsupply.com/bearings/moun...MInqOE6ffJ5wIVQv_jBx0SRAXNEAQYASABEgKrgfD_BwE

I think your type of bearing is more correctly called "mounted bearing." My project doesn't have room for that type. My attached picture from McMaster-Carr basically shows the type of bearing I'm going to use. Notice its flange.

 

[SeniorSitizen]

That's why I mentioned shooting the dark because we have no idea what you have in mind other than increasing a hole size.


I've ordered and installed several dozen flange bearings and the supplier seemed to know what a flange bearing was and shipped me just what's pictured in the link. Maybe you could inform the industry that the one in the link is a mounted bearing.

 

[m_ridzon]

I've ordered and installed several dozen flange bearings and the supplier seemed to know what a flange bearing was and shipped me just what's pictured in the link. Maybe you could inform the industry that the one in the link is a mounted bearing.

Sarcasm noted.

 

[SeniorSitizen]

As usual, when it comes from the opposite direction it's always sarcasm.

 

[SPS-1]

This is another great idea. Do you have any links for where I can buy one?

I normally buy from a local shop, but just do a google search for "boring head" and you will get lots of hits. Amazon seems to have a bunch. Don't forget to buy a tool bit too. I have probably been using the same tool bit for a decade, but a drill press is not going to have a fine feed handle for lowering the chuck. Might want to buy a spare tool bit.

You would likely still be best off to drill a big a hole as practical, and just doing final sizing with the boring head ---- 5/8 to 1-3/8 is a lot of steel to remove.


.

 

[Calson]

There are reduced shank drill bits that have a 1/4" shank and can drill a 5/8" diameter hole. Use this in place of the pilot bit in the hole saw arbor and attach a 1-3/8" bimetal hole saw.

There are tools to allow making large holes by attaching two hole saws back to back but I doubt that they would work with a 5/8" size hole saw.

Another approach is to make a 5/8" plug with a 1/4" hole and use it to keep the arbor with a hole saw in position.

Third option is to tack weld a steel 1/4" ID washer to the piece and then when you cut out the larger hole it will become part of the scrap piece.