Techsew 4800 Walking Foot Pressure Question

[Arturomex]

I'm having an issue with my 4800 walking foot leaving marks on veg tan leather. This machine is, I think, a hybrid clone of the Juki LS 1342.

I've loosened the pressure spring all the way and still have the problem. I believe that when I back off the pressure on the back foot the situation improves but I'm not certain about that. Are the pressure of the rear foot and walking foot interrelated?

My feed dog is set to 6.0mm. The spec calls for 0.8mm +/- 0.1mm for the LS 1341 and 0.5mm +/- 0.1mm for the LS 1342.

Lift height is to spec at 9.0mm with the hand lifter and 16.0mm with the knee lifter.

I'd really appreciate any insights on how I can correct this situation.

Thanks,

Art

[kgg]

5 hours ago, Arturomex said:

My feed dog is set to 6.0mm.

Maybe something to try:

i) Check to see if the presser feet are properly set: ( https://www.youtube.com/watch?v=hGKAtLjppnc

ii) reset the feed dog to the Juki LS-1341 spec. I think the nose of the Techsew is that of LS-1341 not the LS-1342 ( http://baltorfina.lt/wp-content/uploads/katalogas/juki-iranga/pdf/LS-1340_en.pdf ) I am assuming it was a typo, O.6mm.

 

iii) buy a smooth presser foot example would be ( https://sewinggold.com/product/juki-ls-1341-smooth-feed-dog-for-leather/?srsltid=AfmBOoq6yRWm-JtSXDLyQhiSR5tLF7NnyJpPIZ9ji1by1g7qMFut4SiH ) or fill the teeth of the old one and grind smooth with JB weld or grind the teeth off and reset the height.

iv) try a Smooth Bottom Welt Foot similar to ( https://www.amazon.ca/KP-19160-Walking-Compatible-Replacement-Brother/dp/B095BWH832/ref=asc_df_B095BWH832/?tag=googleshopc0c-20&linkCode=df0&hvadid=706835590232&hvpos=&hvnetw=g&hvrand=5201337836443856463&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1002376&hvtargid=pla-1952777302750&psc=1&mcid=9bb67bf3649938d7a1b7d55966d41309&gad_source=1 )

v) Download the Juki manual ( https://semsi.com.mx/Manuales/JUKI/LS-1340&42-7EM01_e.pdf )

kgg

[Arturomex]

Thanks for getting back to me, Keith.

Typo indeed. Should have read 0.6mm on the feed dog height. My problem is, I think, that there is just a little too much pressure on the walking foot.

i) Yes the feet are properly set.

ii) The nose is, indeed, the same size as the 1341. I could raise the feed dog 0.2mm but I don't think that would help reduce the impression from  the walking foot. It's currently set to the height it shipped at.

iii) The machine shipped with a smooth feed dog.

iv) All my presser feet are smooth.

v) Got the manual and the 1342 Parts List as well.

Techsew has this video up: https://www.youtube.com/watch?v=EjW5ucfkDII

It doesn't address the position of the walking bar spring when performing this but I'm wondering if I can take a tiny bit of pressure off the walking bar this way.

What do you think?

Art

 

[adventureleather]

I have had both 5100 and 4800, now a 205. The 205 is similar to the 5100/441 and leaves less marks than I have seen. Go figure. 

Something I always do is on a grinding wheel, I curve the sides, and back of the presser feed then hand sand them. After that I polish with my knife compounds. These machines need to be tailored to your type of leather since out of the box they are just generic. I love Herz Bags and watch their videos, some machines look super old and customized. I also sand down the throat plate and feed dog if needed. Next you can look at the presser spring, if it is all the way up and still too tight you can snip off a few coils of the spring. Be sure to have a spare incase though. I did that on the 5100, but didn't need to on my 205. I would start with the feet since rounding off the edges won't make a pronounced hard edge in the mark, but more a depress that can be hammered out. Be sure to watch for the material slipping though you're stitch length will change. If you top tension is too tight that will also move the material as the foot walks on a low pressured presser foot. 

If you don't want to grind the original feet, I get feet off of eBay and customize those since they are cheaper to replace. 

 

Also don't forget if you raise the feed dog, you're adding pressure. You'll have to make a machine adjustment to the new height with the centre foot and that just more fiddling. Those are some things that have helped me with chrome tan and veg tan like buttero. Some chrome tan that marks easy had bad marks before with the harder edges of the foot not rounded. 

[Arturomex]

Thanks. Appreciate the advice and feedback.

Got a couple of springs on order and, oddly, was at the grinder when you were posting your reply.

I'll let you know how it works out.

Art