Convert Harbor Freight 20 ton press to 32 ton

[Steve]

I got a great deal on an excellent product from HF which is their 20 ton hydraulic press. $149 out the door. My old 25 ton press cracked after 20 years of use so I decided to get the HF 20 and modify it. The press is a bit sloppy with the pin moving front to back and right to left way too much so I did a bit of modifying along with increasing the tonnage to 32 with the addition of a new air/hydraulic jack.

The HF hydraulic press is rated for 20 tons which is plenty for most but I am going to be bending some fairly thick metal and I wanted the air / hydraulic option so the hand 20 ton jack was replaced with a 32 ton a/h jack.

The press itself is pretty heavy duty but will not withstand 32 tons without reinforcing it in key areas.

On the top, I added on both sides some 5/16 plate that I cut with my Power Plasma 50. What a great machine! Cut through it like butter. I probably could have gotten away with 1/4 inch plate but I may in the future go to an even heavier tonnage. So 5/16 was it.

On the side C channel, in order to tighten up the sloppiness of the jack carraige, I added some 1/16 inch by 1 inch by 12 inches of flat bar metal to both sides of the C channel supports. Had to grind it down a little to allow for smooth movement but it was worth it. I also bent the small C channel in on the carraige to cut down on front to back movement.

On the bottom, I added some 3/4 inch rod to keep the supports from bending. It really stiffened up the whole frame.

To top it off, I added a 32 ton air-hydraulic jack. Had to cut out the old circular top of jack guide and replace it with a larger one to fit a 32 ton jack. I cannot describe how much nicer it is to have air hydraulic instead of the standard pump jacks. I mean like magnitudes better. It changed this press from being a pain in the butt to use to one that I look forward to using. It is that much better.

Had some problems with Harbor Freight mig wire. I won't use or buy it ever again. It was oily and would not weld worth a darn. Arc was erratic and welds were poor. I would not recommend Harbor Freight mig wire. There are many lists on the internet about which HF products are good and which are not. I would recommend checking it out before you buy!

I would also recommend that anyone who has a Harbor Freight Hydraulic press to get a good thick piece of steel to put over or under your cast iron arbor press plates. Those cast iron plates have in some cases broken apart with some force so they can be dangerous.

I could not have done this without my Power Plasma 50. I cannot say enough about how great that machine is!

I have not painted it yet but I will be sandblasting it and then powder coating it.

[sportbike]

the air over hydraulic will be a great addition. Time to make up a metal brake for it now that it won't take 2 hours to pump for each bend. .

[zoama]

Do you think the bed and pins will take 32 tons ?

[Steve]

Do you think the bed and pins will take 32 tons ?

I recently reinforced the bed and changed the pins to 1 inch along with reinforcing the C channel on the sides with 1 inch diameter opening grade 8 washers welded in place. I found out last night (after reading the manual) the the jack I am using is actually rated at 72,000 lbs. and not the 64,000 lbs I thought it was. So it is a 36 ton jack even though I thought I bought a 32 ton.

I have noticed that the bed did bend a little with 36 tons on it noticeably even with the 1 inch x 8 inch plate on top of the cast iron plates. So last night (at 3 am) I welded the 5/16 inch plate to the bed along with adding the 1 inch pins (made from grade 8- 1 inch by 1 foot long machine bolts) and welded on the washers. The pins are not getting any marking on them like the 3/4 inch factory pins were getting and now the flex on the bed is a lot less.

The jack carriage modification really helps with pressure pin stability. I was not happy with the way the carriage was moving between the C channel supports with movement right to left and forward and back. Like about a quarter inch each way! By adding the sixteenth inch thick metal on both sides to the C channel, it stopped the movement and bending the tabs on the carriage stopped the forward and back movement. Now it moves almost like a high end hydraulic press with no wobble on the carriage.

It should be illegal to sell these presses with a manual pump jack. The air option is so much nicer and quicker.

I had to scrap my old 25 ton manual pump hydraulic press after over 20 years of hard use. It was developing cracks and the jack was leaking pretty badly. I also needed a little bit larger press so I put the old one up for sale on Craigslist with the new 20 ton jack that came with the Harbor Freight press and it sold in a day for almost the price of the new air hydraulic jack.

Overall besides having to move the press from my garage upstairs and down to the basement several times, this was a pretty fun project to do.

[Steve]

the air over hydraulic will be a great addition. Time to make up a metal brake for it now that it won't take 2 hours to pump for each bend. .

Yep! Already in the works. I priced out the cost of material and springs plus my labor and found that the Swag Off Road brake kit for the Harbor Freight 20 ton press was a better bet as far as cost is concerned. So I have one on order (the heavy duty version) and should get it in a couple of days.

Jody at Welding tips and tricks dot com recently did a video on that kit and how to weld one together. I've heard that the Swag kit is pretty nice with a lot of folks talking about it on the internet.

[zoama]

Yep! Already in the works. I priced out the cost of material and springs plus my labor and found that the Swag Off Road brake kit for the Harbor Freight 20 ton press was a better bet as far as cost is concerned. So I have one on order (the heavy duty version) and should get it in a couple of days.

Jody at Welding tips and tricks dot com recently did a video on that kit and how to weld one together. I've heard that the Swag kit is pretty nice with a lot of folks talking about it on the internet.

I have a 20 ton HF press and a 20 ton air/hydraulic jack. I ordered a swag heavy duty brake without backstop last weekend. I also got 3' of "1x4" cold roll to make arbor plates since premade ones are 2.5 x the price of cutting your own.

[Steve]

I have a 20 HF press and a 20 ton air/hydraulic jack. I ordered a swag heavy duty brake without the backstop last weekend. I got an order confirmation but never got a shipping notice and they don't respond to emails or answer the phone. Have you had any contact with swag or got a shipping notice ?

No, they won't answer the phone and you will not hear from them. I guess he is a one man operation and he spends his time building things. All I know is that when you order, you will get a confirmation and then it will one day soon show up. He is pretty good on shipping and filling orders from what I have heard from others.

It probably will come via US postal service. The price you pay includes shipping.

[zoama]

No, they won't answer the phone and you will not hear from them. I guess he is a one man operation and he spends his time building things. All I know is that when you order, you will get a confirmation and then it will one day soon show up. He is pretty good on shipping and filling orders from what I have heard from others.

It probably will come via US postal service. The price you pay includes shipping.

Thanks for the info... I edited my previous post.

[SeanMurphy265]

Swag seems to ship in the priority mail boxes to save $$. I like his arbor plates. I'm going to break down and get a set.

[zoama]

Swag seems to ship in the priority mail boxes to save $$. I like his arbor plates. I'm going to break down and get a set.

You have the tools to make your own and save over $100

[DVA]

I have noticed that the bed did bend a little with 36 tons on it noticeably even with the 1 inch x 8 inch plate on top of the cast iron plates. So last night (at 3 am) I welded the 5/16 inch plate to the bed along with adding the 1 inch pins (made from grade 8- 1 inch by 1 foot long machine bolts) and welded on the washers. The pins are not getting any marking on them like the 3/4 inch factory pins were getting and now the flex on the bed is a lot less.

How was the 5/16 plate welded on, along the inside of the C-channels?

[Steve]

How was the 5/16 plate welded on, along the inside of the C-channels?

I welded the plate on the outside so the C channel is boxed. It now is really heavy and will not bend too much. I put a dial indicator on the bed prior to welding the channel and it was deviating by .11765 with the jack at max. After the welding, the bed deviated by .0162. Quite a difference. The bed when used not reinforced, would bend back but would not bend back totally. I would lose about .001 of an inch. Not a lot but over time would add up if I use this a lot. Now that it is reinforced, I cannot measure with my digital dial indicator the return. I think It's going to be good.

I may end up reinforcing all the C channel on the main frame with plate. I have noticed a slight twisting on the frame if anything is not exactly straight. I may even add an external C shaped frame at the back of the press to keep twisting down.

This press now can handle the 35 Tons the jack can output. And it now weighs almost twice what it did when I got it!

[DVA]

I welded the plate on the outside so the C channel is boxed. It now is really heavy and will not bend too much. I put a dial indicator on the bed prior to welding the channel and it was deviating by .11765 with the jack at max. After the welding, the bed deviated by .0162. Quite a difference. The bed when used not reinforced, would bend back but would not bend back totally. I would lose about .001 of an inch. Not a lot but over time would add up if I use this a lot. Now that it is reinforced, I cannot measure with my digital dial indicator the return. I think It's going to be good.

I may end up reinforcing all the C channel on the main frame with plate. I have noticed a slight twisting on the frame if anything is not exactly straight. I may even add an external C shaped frame at the back of the press to keep twisting down.

This press now can handle the 35 Tons the jack can output. And it now weighs almost twice what it did when I got it!

0.016 of an inch deflection is not bad compared to 0.117 of an inch. The C-channel in now 7.31 times stiffer than the original design.

Also if the bed was bending but not bending back totally before, the bed was plastically deforming and would have failed if not reinforced.

[zoama]

I recently reinforced the bed and changed the pins to 1 inch along with reinforcing the C channel on the sides with 1 inch diameter opening grade 8 washers welded in place. I found out last night (after reading the manual) the the jack I am using is actually rated at 72,000 lbs. and not the 64,000 lbs I thought it was. So it is a 36 ton jack even though I thought I bought a 32 ton.

I have noticed that the bed did bend a little with 36 tons on it noticeably even with the 1 inch x 8 inch plate on top of the cast iron plates. So last night (at 3 am) I welded the 5/16 inch plate to the bed along with adding the 1 inch pins (made from grade 8- 1 inch by 1 foot long machine bolts) and welded on the washers. The pins are not getting any marking on them like the 3/4 inch factory pins were getting and now the flex on the bed is a lot less.

I wouldn't use grade 8 bolts for support pins because the harder steel will shear instantly rather than bend or deform. A grade 5 bolt is a better choice for shear stress.

[Steve]

I wouldn't use grade 8 bolts for support pins because the harder steel will shear instantly rather than bend or deform. A grade 5 bolt is a better choice for shear stress.

That is an interesting comment.

I did a bit of research and before I made my decision, I needed to know the shear strength of a grade 5 and a grade 8 bolt at 1 inch thick.

Here is what I found according to Mark's standard Handbook for Mechanical Engineers:
Here is the link: http://www.rockcrawler.com/techrepor...ners/index.asp


A one inch grade 5 bolt shears at 58,900 lbs.

A one inch grade 8 bolt shears at 71,500 lbs.

The surface area where the bolts will contact the side of the frame has been doubled with the addition of 1 inch grade 8 washers welded to the supports on each hole. Each pin or bolt would have two contact points each for a total of four contact points with the frame. So each contact point would have at least 14,725 lbs on them. But, the tops of the pins will have no pressure so you would have to increase the pressure on each of the points to about 17,600 lbs on each contact.

So, yes I could have used grade 5 bolts and it would have a very good safety factor.

Each grade 8 bolt has a shear strength each that is at about the capacity of my hydraulic jack. Just one bolt alone!
The safety factor in having 4 contact points (which has been increased in surface area) is way more than I would ever need. The grade 8 bolt has 12,600 lbs of more shear capacity (over 6 tons) over the grade 5 bolt.

I highly doubt that I could ever break these bolts with the setup I have. But I agree, a grade 5 bolt would have saved me some cash and would have been just fine for my use.

I may in the future go with a 50 ton air hydraulic set up. The grade 8 bolts would still be fine for that. The only thing that I would have to worry about is the frame which could be a problem. I am going to eventually install tubing inside the C channel and also add 5/16 plate to box the frame in for even more strength. I want to do some hole punching and a 50 ton press would really be the cat's butt!

[zoama]

That is an interesting comment.

I did a bit of research and before I made my decision, I needed to know the shear strength of a grade 5 and a grade 8 bolt at 1 inch thick.

Here is what I found according to Mark's standard Handbook for Mechanical Engineers:
Here is the link: http://www.rockcrawler.com/techrepor...ners/index.asp


A one inch grade 5 bolt shears at 58,900 lbs.

A one inch grade 8 bolt shears at 71,500 lbs.

The surface area where the bolts will contact the side of the frame has been doubled with the addition of 1 inch grade 8 washers welded to the supports on each hole. Each pin or bolt would have two contact points each for a total of four contact points with the frame. So each contact point would have at least 14,725 lbs on them. But, the tops of the pins will have no pressure so you would have to increase the pressure on each of the points to about 17,600 lbs on each contact.

So, yes I could have used grade 5 bolts and it would have a very good safety factor.

Each grade 8 bolt has a shear strength each that is at about the capacity of my hydraulic jack. Just one bolt alone!
The safety factor in having 4 contact points (which has been increased in surface area) is way more than I would ever need. The grade 8 bolt has 12,600 lbs of more shear capacity (over 6 tons)

I highly doubt that I could ever break these bolts with the setup I have. But I agree, a grade 5 bolt would have saved me some cash and would have been just fine for my use.

I may in the future go with a 50 ton air hydraulic set up. The grade 8 bolts would still be fine for that. The only thing that I would have to worry about is the frame which could be a problem. I am going to eventually install tubing inside the C channel and also add 5/16 plate to box the frame in for even more strength. I want to do some hole punching and a 50 ton press would really be the cat's butt!

You want it to fail slowly if it fails. A grade 5 will deform a little before it shears or bend before it breaks. As long as you're happy with it that's all that counts.

[MuttonHawg]

Perhaps a stupid question, but considering how much you've modified this press reinforce it, do you have an estimate for how much more/less it would've cost to just build your own? Plus, then you could design the dimensions (wider, for instance) to whatever you'd need rather than be constrained by the dimensions of the existing press.

Or, posing the question another way: having gone through this process, would you consider building your own, or stick with the reinforcement of an existing HF press?

[youngnstudly]

Wow, I didn't realize all that you did on this press to convert it! I must have missed reading a portion of your post regarding the bad MIG wire, or it didn't register with me! Do you send your items out to be powder coated and sand blasted, or is this a setup you have in a shop that allows you to do the work yourself?

That Swag Offroad brake kit is very nice for turning your standard press into a very capable metal brake! That site has some other very useful DIY home fabricator type projects as well. I've had my eye on a few of their shop tools for a while.

[Steve]

Perhaps a stupid question, but considering how much you've modified this press reinforce it, do you have an estimate for how much more/less it would've cost to just build your own? Plus, then you could design the dimensions (wider, for instance) to whatever you'd need rather than be constrained by the dimensions of the existing press.

Or, posing the question another way: having gone through this process, would you consider building your own, or stick with the reinforcement of an existing HF press?

Not a stupid question at all!

I did do some calculations on getting all the metal and building from scratch. Scratch would be about 30% more than getting a Harbor Freight 20 ton and modifying it. I got a really good deal on the HF press, $149 out the door. My local HF is just a few miles away. The closest metal store is 45 miles away. So I saved on gas. I had scrap metal laying around from other projects and so the cost of all the extra metal was not an issue. I also got a pretty good deal on the air /hydraulic jack on E-bay with a 15% off coupon. That cost me $132 with free shipping.

The design of the HF press is a pretty standard design and it does have some pretty good strength to it. With all the changes, I almost doubled the weight of the press and was able to use up a lot of scrap steel laying around and put it to use. Most of the work on the press was already done. Holes just needed to be widened from .75 to 1. And then just adding metal to the places that need it. I've never really needed anything wider than 22 inches so the HF press works for me. I had a 25 ton press and it sometimes was a bit less than what was needed. The new jack is actually rated at 35.2 tons or 70,400 lbs. .

I guess it comes down to circumstances. I was needing a new press. Harbor Freight had a sale on theirs. I saw the 32 ton jack on E-bay and had a 15% off coupon. I had lots of leftover steel. If any one of those things did not happen, I probably would have just built one from scratch. But then again, I'm pretty happy with what it has become so I think I made the right choice in modifying the 20 ton.

[Steve]

Hello Andy. I do my own sand blasting. I have a source for powder coating but I rarely use it. I prefer paint as powder coating when damaged is a pain to fix.

All my work is done in either my basement or garage. I do build things to sell and it helps pay the bills and keeps me out of trouble.

Yeah, I had some Harbor Freight mig wire and it gave me all kinds of trouble. So I scrapped all the mig wire I had from them and use only Lincoln, Hobart or my local welding store brand which I prefer over them all. I only use the Lincoln or Hobart if I run out of wire on a weekend and so Home Depot or Tractor Supply gets a little business.