Manual singer hd110 - Singer 1507

On the back there should be a lever to push up. Most singers are similar. Try using your left hand to raise the lever

If you haven't replaced the needle then do so. If replacing needle doesn't help, then likely the hook is barbed or there are burrs on the hook body and/or inside the hook race.

https://www.sewingpartsonline.com/instruction-manual-singer-hd110.aspx

Manual for sale - HD110 - unsure if HD110C is the same machine or not. Please let us know.

https://www.manualslib.com/manual/154316/Singer-Hd-110.html

Free manual:

Singer HD 110 Instruction Book

Singer HD 110 Instruction Book

Here's a link to the manual for the machine. You should find your answer there.
Singer Sewing Machine User Manual ManualsOnline com

Be sure to try a brand new needle first. If it still doesn't pick up the bobbin thread, then it possibly is out of time. Search for: sewing machine timing.

You either have a cover in your accessories pack, or there is a lever next to your bobbin case door. I suspect with the drop in bobbin that you have a little dark plastic cover to put over the feed dogs when you darn etc. Your manual should explain all of its uses. If, you didn't get a manual with your machine, call Singer and complain because it is a very important piece. Their number is 1-800-4singer. Make sure that you register your machine with them, also on their site www.singerco.com Good luck and happy sewing.

Yes, if I remember right, it uses a #15 bobbin which is available in metal, but I think that your timing or needle are not right. It may need a good old fashioned tuneup because that is not normal to be breaking a bobbin. Tuneups are usually is not a lot of money and well worth it.

the machine may need oiling
check the bobbin area for lint or loose thread
your belt might be getting loose & need to be tighten up

my wife's hd110 singer machine is not keeping tension. what can I do/ look at to try and help this