PM 3520a toolpost bolt busted

[Jeff Jilg]

The bolt which locks the toolpost in the harp snapped off on my 3520. I had extended the lever with a 6" wooden turned handle and it worked fine for the last 450 bowls/vases. The original lever at 3" just was too difficult to properly tighten.

Of course the toolpost was locked into the harp as well. So after a few choice words I spent the next 2 hours drilling it out and retapping the hole. Now I have a temporary bolt in there which is tightened by a crescent wrench. Has anyone else had this happen, and if so what did you do to fix it longterm?

 

[Chris Wright]

a different fix for the future...

I haven't had that happen yet, but for future reference, instead of drilling the entire hole out and retapping, get an easy-out extractor. It is a neat little do dad with a pointed reverse (left) threaded end. You drill a hole in the old broken bolt, about 1/2 it's diameter and then hand thread the extractor in. As the extractor tightens, it loosens the broken bolt and extracts it from the hole. No need to re-thread. They are generally cheaper than a tap and die set too.

 

[Jeff Jilg]

Yeah, I know about easy outs. I already had the tap/die set. Unfortunately an easy out just wouldn't have worked. Someone (I'm not saying who), really cranked the bolt down before it snapped. Initially I tried to get it out by slotting the end with a dremel and using an impact driver - the kind you hit with a hammer. The bolt and the harp were "one".

This time I'm going to get a higher grade bolt and probably metalwork + weld up a handle.

 

[john lucas]

Brocken 3520 bolt

Jeff
You might try drilling and tapping to a larger size. You can get those adjustable handle from Reid tool supply. I don't remember their web address but you can probably find them with a search.

 

[Jeff Jilg]

Thanks John. I'm really getting tired of the current crescent wrench tightening method after just 2 days. So I appreciate the suggestion.

 

[john lucas]

adjustable handles

Jeff
I'm home now and have the catalog. It is www.reidtool.com They are called adjustable handles and come in heavy duty plastic or metal. They also have heavy duty adjustable handles but they run about $35 to $50. The steel ones are less expensive and would probably work.

 

[Jeff Jilg]

Thanks John, great reference. You're right, they are expensive. I'll have to think about the plastic versions. I noticed that the ridges on the stud (that snapped) were getting worn as well. I dislike using the wrench to tighten the current temp bolts. Maybe I can make a lever similar to theirs to engage the bolt head.

 

[ssinner]

Tool Post Lock

Sounds like you have a 3520A. The 3520 has an exellent clamping system for the tool post.
Don't know if it will make any difference, but I flattened the end of the locking screw on my 3520A, because it was creating indentations on the post. I've never had a problem with the tool post moving with just simple hand tightening, no extension needed.

 

[Jeff Jilg]

You're right Steve, it is a 3520a. When I replace the bolt(s) with a new solution I'll grind the ends flat like you suggested.

 

[Jake Debski]

Jeff,

Although I've never had the tool rest slip, I've never liked the the small lever supplied with the 3520a either. I know $35 seems like a lot of money for a handle but I would give it serious consideration. Especially since you need to increase the bolt size anyway.

 

[Chris Wright]

justification

That and if you figure you'll probably have that lathe for 10 more years or longer, it's only $3.50 per year. That's less than you'll spend in sandpaper!

 

[Mark Mandell]

Jeff,

Go to Reid and get yourself a proper handle rather than trying to "nickle & dime" a shortcut solution. You will validate your choice every time you set and tighten the piece because your tool will work as its supposed to, and your concentration on the turning will improve simply because you won't have that corner of your mind always wondering if the "damn thing's gonna slip again."

All machinery needs maintenence. Putting $50-60 into that $2,300 lathe to return it to proper function is to be expected from time-to-time. I dare say that if you really needed a new gouge because the "old" one broke, you'd have far less trouble justifying the same or even greater expense to replace it.

Suggestion: When you drill and re-tap, be sure to use the coursest thread possible. That leaves more "meat" in the hole and greater holding power in an application that requires constant stress and relief. Getting a harder bolt may not solve your problem as the whole assembly is only as strong as BOTH the bolt AND the threads in the casting or plate.

Hope this helps. Your mileage may vary

Mark Mandell

 

[Jeff Jilg]

I agree with you guys and generally think this is good advice. I agree with Mark that machinery needs regular maintenance, and I've definitely put a lot of hours on this machine without any significant required expenditures. The 3520a is a darned stout machine.

One problem with the Reid handles is that they are almost the same as the last one. Namely 3" long (3.15" for 3/8 16tpi). I had overlaid a 6" turned handle over the old one so it had better leverage. Sure, I might do the same and just buy another 3" handle which gets modified. But if I can put in the same time and create a 6" handle then it will achieve the desired objective. In any event I appreciate all the pointers and helpful suggestions.

At this point I have about 20-30 more roughouts to get through, in order to process all the standing wet/moist wood. Then I'll go back and start finishing some of the 400 roughouts. Roughed out a 14" tall Cedar Elm vase yesterday, which is pretty much at the limits of my current tools. So the lathe is going to get used a lot more and I need to solve this.

 

[Texascop47]

I have had my 3520A since January and havn't had a problem with the tool rest slipping. I just tighten both handles had tight but would agree IF the handle was maybe a little bigger it would feel better. I would spend the extra and get a good handle that will last as long as this wonderful lathe. Maybe Powermatic is listening and will up grade the handles.