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BaronJ
26th Jun 2017, 02:36 AM
Hi Guys,
I've just come back from visiting a friend down south and having a play in his workshop. One of the thing that caught my eye was his use of some toggle clamps that he had bought from the local MSC. These were cast metal and looked quite crude but effective. So I thought that I would make a pair for myself. I've spent the afternoon drawing up my plans to fabricate a pair suitable for use on my mill and also on my press drill table. I've done a JPEG from the DFX file drawn in Qcad.

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I've used materials that I already have on hand so hopefully I won't have to go chasing any bits. The side plates are 3mm mild steel plate. I propose to fasten two pieces together and machine them as one. I also have a couple of foot of 6mm bright bar that I propose to use for the spindles and spacers.
The pressure pads are going to be made from 13 mm diameter brass bar. I haven't made the legs two different lengths as in the MSC ones, but should it be desired the pivot can be offset to one side and the dimensions adjusted accordingly.

bwal74
26th Jun 2017, 06:03 PM
Hi,

Make sure you post some pic's.

Cheers Ben.

Anorak Bob
26th Jun 2017, 08:26 PM
Hello BJ,

I have a couple of pairs of toggle clamps and they they have proved invaluable. Mine are cast iron and the "nose" is fairly squat providing, in the case of my mill, some even more invaluable Z clearance. If vertical clearance was an issue for you, could you reduce the clamp height by knocking off the sharpish top corners of your side plates? I know you are trying to utilise existing material but maybe an increase in side plate thickness might also facilitate some height reduction. Also the rollers don't really need to roll. They could simply be solid steel bar plug welded in position.

368524


BT

Oldneweng
26th Jun 2017, 09:24 PM
Hi Baron,

In your drawing it says "Drill & thread to suit your T nuts" under the Pivot diagram. I don't understand this. I would have thought you need a clearance hole so you can tighten the clamp down.

Dean

BaronJ
26th Jun 2017, 11:08 PM
Hi Bob,
Those clamps look very meaty. Much more robust looking than the ones my friend had. I decided on brass rollers because his had flat brass strips round the ends.
I had thought about welding the end of the pins instead of using a press fit. My wife has bought me an Inverter TIG welder for our 45th wedding anniversary, so I'm looking forward to having a play with it.

BaronJ
26th Jun 2017, 11:13 PM
Hi Dean,
Doh, yes you are right ! It should be a clearance hole.
I was thinking about the threads in my "T" nuts at the time. I've got "T" nuts with both M8 and M10 threads.
I will amend the drawing and re-post it.
Thanks for letting me know.

BaronJ
26th Jun 2017, 11:19 PM
Hi Guys,
Dean kindly pointed out an error on the original drawing that I posted. So here is a corrected one.
Sorry about that.
:-:-:-

368532

BaronJ
30th Jun 2017, 03:57 AM
Hi Guys,

Taking note of Bob's suggestion about making the side plates thicker and the way that I decided to go about making a pair of clamps, I did a redraw using the centre of the outside radius as a reference point. Also the Jpeg image seemed quite poor so I've uploaded this one as a pdf file. If anyone wants a copy as a jpeg, just shout out.

368579

I originally was going to use 3mm plate, simply because I had some handy. I came across a length of 6 mm thick by 35 mm wide black bar. Much easier to cut with a hack saw :)
Anyway I hacked four 75 mm long pieces off and then squared then up on the mill.

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After deburring I used this cleaned up end as the reference point to mark out the positions of the five holes needed. Using a 1/4" centre drill and the hand wheel dials I started at one end and did each piece in turn.

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When I had marked out all five holes in all four pieces. I then drilled them all out 6 mm diameter. I then opened out the middle hole with a 16 mm counterbore having a 6 mm pilot.
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More to follow.

jhovel
30th Jun 2017, 04:16 AM
Baron, have a look at some valve rocker arms of small stationary engines. You might find some suitable forged steel toggles there.....

BaronJ
30th Jun 2017, 07:57 PM
Good morning Joe,

It was more like the clamps took my fancy as a project rather than anything else. Since it is chucking it down at the moment, working outside is out of the question and I need to spend some time in the workshop anyway. But thanks for your suggestion.

Oldneweng
30th Jun 2017, 09:47 PM
Good morning Joe,

It was more like the clamps took my fancy as a project rather than anything else. Since it is chucking it down at the moment, working outside is out of the question and I need to spend some time in the workshop anyway. But thanks for your suggestion.

Chucking it down? What happened to the heatwave?

Dean

BaronJ
1st Jul 2017, 06:28 AM
Hi Dean,

The heat wave petered out a couple of days ago. Since then it has done nothing but rain here. We have had 75 + mm in the past 48 hours. At the moment the rain has stopped but it is grey and miserable, the weatherman has promised us a better weekend. Haa, where have I heard that before...

Oldneweng
1st Jul 2017, 09:47 AM
Ahh. So back to normal then? We are having a pretty dry winter. Started well with good early rains, but then it sort of petered out. :rolleyes: Last year was the wettest winter for decades following on from a drought that lasted for many years. A drought in my area would be considered a flood in some areas, but still causes serious issues. There is a reservoir to the East of here that was down to 3% of capacity. Full it is 67.5 square km in area. It is currently at 43%. The highest I have seen it recorded.

Dean

chambezio
1st Jul 2017, 10:30 AM
You know there will be no weather men in heaven...................














They are all liars.

Oldneweng
1st Jul 2017, 10:46 AM
I would not like a job where your work is just a constant procession of failures.:D

Dean

BaronJ
1st Jul 2017, 09:18 PM
Hi Guys,

First the weather :) A little rain overnight, but I woke up this morning to bright sunshine, with a few fluffy clouds overhead. It won't last though, you can see the cloud bank approaching from the west.

Now onto the Toggle Clamp.

I mentioned that I had re-drawn the drawing to use the radius centres as the reference points. This was so I could make a simple jig that I could use to turn the smaller radius using the lathe. It also meant that I could machine all four pieces at one go and to prevent balance issues machine them as pairs. To this end I used a square piece of hard PVC 1/2" inch thick.

368600 368601 368604 368605

I marked out the centre of the piece of PVC, then scribed a circle 39 mm radius and then another circle inside that one to match the 33 mm roller shaft centres. I marked it with a red ink marker so that I could see it. I then drilled a hole in the centre of it 5 mm diameter and threaded it M6. At this point I placed it on a mandrel held in the lathe three jaw chuck and then turned it down As you can see there is a small flat on one edge. This happened because the PVC wasn't quite a square. However this was also convenient because I used it to identify jaw one of the chuck. If I had to remove the work, I could put it back in exactly the same position.

After turning it down I marked and drilled a hole 5 mm diameter, centered on the scribed line. I threaded this hole M6 also. I measured across and marked three other hole positions to match the outermost two holes in the toggle clamp side plates. These were also drilled 5 mm and threaded M6.


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I did check to make sure that the holes on all four side plates matched up before I paired them up and using M6 cap screws fastened them to the PVC jig plate. I used 6mm diameter dowel pins to check. I also de-burred all the holes on both sides of all the plates before hand, just to make sure that there was nothing to cause them to not lay flat against each other. As you can see from the pictures.

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At this point I fastened a pair of side plates to the jig at opposite sides of the centre. This ensures that the whole thing is balanced and wont vibrate when being turned to size. One thing that I will point out is that the plates will get quite hot whilst being turned, so care has to be taken that things don't get hot enough to melt the PVC. A sharp HSS tool and small cuts are needed because of the interrupted cut. Try and take a big cut and there is a danger that the lathe will stall. I keep the belt a little loose when doing things like this, at least it prevents any damage.


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I stopped at this point. I felt that the work was getting hotter than I was comfortable with and I didn't want anything coming loose on me.


Thanks for looking and all the likes :):):)
More to come, but it will be after the weekend, visiting youngest Granddaughter.

Anorak Bob
2nd Jul 2017, 12:43 AM
Nice work BJ.:2tsup:

Is that chuck attached to a Super 7 ? :)

BT

BaronJ
3rd Jul 2017, 11:56 PM
Nice work BJ.:2tsup:

Is that chuck attached to a Super 7 ? :)

BT


Hi Bob, Thanks for the thumbs up.
Yes it is. The lathe is about 35 years old now, I bought it new from Myford in Nottingham.

BaronJ
15th Jul 2017, 12:25 AM
Hi Guys,

I've managed to get a little more done on the toggle clamps.

368794 368795
As you can see I have finished both of the curved edges. I was going to mill the small radius on the ends but decided that it would be quicker to file them round. I also decided to change the construction a little. I made four pins from 7.5 mm round rod and turned the ends to be a good fit in the side plates. By doing this it meant that by setting the length of the thick part I could determine the spacing between the side plates, the intention is to locktite them in and if necessary TIG the ends . I also turned a couple of rollers from 13 mm red bronze rod, drilled them M6 and parted off to length. I still have four 6 mm spindles to cut to support the rollers and the two large pivots for the middle.


PS. If I were going to do this again to make the side plates, then I would use the lathe faceplate. Turning the inside radius of the curve is right up against the maximum diameter you can cut on the Myford. Bear in mind that the side plate is 26 mm from the inside to the outside. The other option would have been to use the mill and rotary table.

More to follow.

BaronJ
16th Jul 2017, 03:13 AM
Hi Guys,

I've gotten some more done on these toggle clamps and apart from a pivot pin and a pair of rollers they are finished.

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The pictures above show one of the side plates along with two spacers and two roller pivot pins. The roller pivot pins were just parted off to length from 6 mm drill rod with the ends chamfered with a file whilst still in the lathe chuck. The third picture shows the washer that goes under the securing nut, and does double duty as a spacer between the side plates preventing the pivot pin from moving sideways and providing a flat surface for the nut to tighten onto. These were made from black bar turned to size, drilled and parted off. They are 6 mm thick. The fourth picture is the assembled clamp minus the red bronze rollers and before the pivot pin is drilled. More about that later.

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The first three pictures above show the completed clamp on its M8 threaded stud. The last three are views of various stages of assembly.


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Now I said above that I would say more about the pivot pin ! It is a piece of black bar turned to size and parted off to a length of 30 mm. I polished it with fine emery cloth (300 grit) in the lathe before parting. I also used a short piece of the same emery cloth wrapped on the end of a short length of 15 mm diameter wooden dowel, held in a saw cut to polish the inside of the pivot holes in the side plates. I found that the drilled surface was sufficiently rough to cause the pivot pin to bind in the hole. A drop of oil helps as well.

Next was setting up to drill the M8 hole through the centre of the pivot pin. I marked the centre line from each end and set it up in a drill vice. Using a centre drill and a steel rule I found the centre line of the pivot pin and then drilled it. After swapping the centre drill for an 8 mm drill I drilled right through. Using a Weldon countersink I de-burred the top of the hole then turned it over. Putting the 8 mm drill back in the chuck I squared up the pivot pin and de-burred the other side. A quick rub with emery cloth removed any remaining burrs.

Right Guys, that's it for this project.
Thanks:

Anorak Bob
16th Jul 2017, 10:22 AM
Very nicely executed BJ and wonderfully documented. Thank you.

Bob.

KBs PensNmore
16th Jul 2017, 10:14 PM
Thanks for the excellent WIP report Baron. Looking forward to seeing the next project.:D
Kryn

Steamwhisperer
20th Jul 2017, 07:17 AM
Great job Baron and great documentation, many thanks.

Phil

shedhappens
22nd Jul 2017, 11:22 AM
Very nice and practical job Baron, it was particularly smart and interesting to see the use of the PVC for the jig, to be honest I would have never even contemplated using PVC, I rarely have ever machined it I suppose.

cheers, shed

Grahame Collins
28th Dec 2021, 12:22 PM
Hi Benizel,

Welcome to the MetalWork forums,

Why not tell us about your self and your metalwork interests and tools ,equipment you have.

There's an ideal place at the Welcome Wagon forum - https://metalworkforums.com/f300

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do this: To navigate our Forums click on the FORUM box at the LH top of the page.

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Anything else you need to know,please PM me and I will help if I possibly can.

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